PDF DOWNLOAD: Yale B801 (OS030EB) Forklift Operating Manual

Sheet 1: Operating Instructions OPERATING INSTRUCTIONS

Figure 1-1 -OS030EB Truck MODEL DESCRIPTION The Yale OS 030 EB electric lift truck has a 3,000 lb. lifting capacity and is specially designed for order picking. The power source is a 24 volt battery. The operator's platform is elevated with the load. This allows accurate fork positioning and order picking operations. The lift truck can be operated from the standing position with the operator facing either direction.

NOTE: Throughout this manual the terms left, right, front and rear relate to the viewpoint of an operator standing in the truck facing the steer/drive tire.

The control handle allows the use of one hand to control forward and reverse travel as well as lift and lower. The variable lift/lower control allows the operator the option of varying the lift and lower speeds. The drive motor is stationary to prevent flexing and wear of the power cables. An electrically released, spring applied brake is also provided. Yale Hi-Vis Triplex masts provide excellent visibility for these models.

Before attempting to operate this lift truck, carefully read and understand these operating procedures. Make sure the lift truck is in proper operating condition. Be sure all safety devices such as the overhead guard and the tether line and belt are in place and properly secured. The operator should always wear the tether line and belt when operating this unit.

No additions, omissions, changes, or modifications should be made that wilI affect compliance to the stated requirements or in any way minimize the effectiveness of the safety devices.

Sheet 1: Operating Instructions

Figure 1-2 - Instrument Panel OPERATING CONTROLS The numbers and letters in the following descriptions are to be used for component identification. See Figure 1-2 through 1-8.

1. The Instrument Panel includes a Battery Indicator/Hourmeter, a Steering Indicator Gauge, a Battery Power Disconnect, a Slack Chain Warning Light and the Key Switch. On lift trucks that have optional Wire Guidance, a rocker switch and a red light will also be on the instrument panel. The instrument panel is located between the steering wheel and the traction controller.

A. The Battery Indicator/Hourmeter illuminates a light emitting diode (LED) bar to display the battery state of charge. Two red, three yellow and five green colored LEDs are arranged from left to right for a total of 10 bars. The far right LED indicates a charged battery. The far left LED indicates a discharged battery.

When a properly charged battery is installed in the lift truck, the green LED at the far right of the scale is illuminated. As the battery's state of charge decreases, LEDs to the left are successively illuminated.

The illuminated LED moves from right to left and the colors change from green to yellow to red as the battery discharges. The red LED second from the far left will flash indicating a nearly discharged battery.

The battery should be charged at this time. If the last two LEDs are alternately flashing, the battery MUST be charged. Thelift function will be disallowed at this point. Continued operation with the LEDs flashing can damage the battery, motors or the contactors. The battery indicator will automatically reset when a charged battery is connected. The battery indicator functions only when the key switch is in the ON position.

The Battery Indicator/Hourmeter electronically records lift truck hours whenever travel or lift functions occur. A liquid display crystal (LCD) is used to show the current hourmeter reading. The hourmeter utilizes an internal batteryto retain the current hourmeter reading when the lift truck battery is disconnected. The internal battery is not a serviceable part and is designed to last for the life of the Battery Indicator/Hourmeter. Hours are displayed whenever the lift truck battery is connected.

B. The Steering Indicator Gauge allows the operator to see the current position of the lift truck steer tire.

The Steering Indicator Gauge uses red arrow shaped LED's to provide a visual display of the steer tire position.

C. The Battery Disconnect Switch is the red knob located on top of the instrument panel. When the knob is depressed, power will be shut off to all circuits throughout the forklift exceptforthe hourmeter. Turning the key switch to the start position restores power.

D. The Slack Chain Warning Light will let the operator know when the platform or the forks will not lower because of an obstruction. Raise the forks until the chain is taut and the light goes off.

E. The Wire Guidance rocker switch controls the optional wire guidance function. The rocker switch and the red light are both ON when the guidance system is ON. Pushing the switch button to the ON position as the lift truck approaches the guide wire energizes the guidance system to seek the guide wire. During the SEEK mode the light will flash and the alarm will sound. A steady light with no alarm indicates that

Sheet 1: Operating Instructions the guidance system is in the RUN mode. The alarm will sound and the light will flash if the guide wire signal is lost.

F. The Key Switch is a three position switch. The first position is OFF (marked O). The second position is RUN. The third position is START. The key automatically returns to the second position after it is released from the start position.

2. The Control Handle is a multifunctional grip for lifting and lowering the forks, as well as forward and reverse travel. Push the control handle in the desired direction of travel. The amount of control movement determines the speed of travel. The control is spring loaded and will automatically return to the neutral (off) position when released. The two rocker switches in the control handle allow the forks to be lifted or lowered.

Both switches will automatically return to the neutral position when released. The operator can change the direction of travel while the lift truck is moving by moving the control handle to the opposite direction of travel. The lift truck will come to a stop, unless the control handle is released, and accelerate in the opposite direction. This action is called "plugging" and is the normal method of stopping the lift truck.

Figure 1-3 -Directional Control and Horn The Horn Switch is located on the control handle. Push the horn button to sound the horn.

4. Brake Pedal - The brake is applied when the pedal is released. The brake is released when the pedal is depressed. This brake can stop the truck abruptly and is used primarily as a parking brake. The normal method for stopping this lift truck is plugging.

Figure 1-4 -Brake Pedal 5. The Steering Wheel is equipped with a spinner knob. The on-demand electronic power steering draws power on an as needed basis.

Figure 1-5 -Steering Wheel 6. The lift truck is equipped with optional Side Rails which must be lowered into position for lift truck operation.

The Side Rails have electric interlock switches which deactivate drive and hoist functions when they are not in the lowered position.

Sheet 1: Operating Instructions 7. The Pallet Clamp will automatically engage the pallet. The Pallet Clamp Release is a foot pedal on the operator compartment floor.

Figure 1-6 -Release Pedal and Pallet Clamp 8. An Amber Flashing Light is mounted on the drive unit cover. The light will flash anytime the key is in the ON position.

Figure 1-7 -Flashing Light 9. The Manual Lowering Valve, located in the drive motor compartment is manually operated to lower the operator's platform. Turn the manual lowering knob clockwise to open the valve. Turn the knob counterclockwise to close the valve.

WARNING: Make sure Manual Lowering Valve is completely closed before lift truck operation. Unintentional mast lowering may occur if the valve is not closed.

WARNING: Before using the manual lowering feature, make sure there are no obstructions which would prevent the platform or forks from lowering.

10. The Operating Manual is sent with the lift truck and is located in the container on the drive unit cover. The Operating Manual is a permanent reference and must be available for the operator's use at all times. Read and understand this manual before operating the lift truck.

Sheet 1: Operating Instructions

Figure 1-8 -Operating Manual SAFETY AND INFORMATIONAL LABELS Safety and informational labels are located in conspicuous locations on this lift truck and should be strictly adhered to. These safety and informational labels must be replaced immediately if missing or defaced. Labels will vary with type of lift truck and equipment installed. Refer to the Parts Manual for part number of labels.

CAPACITY PLATE Familiarize yourself with the information contained on the capacity plate which is located on the operator's platform.

Capacities and warnings contained on this capacity plate must be strictly followed. Information on this capacity plate is as follows: Serial Number This is an identification number assigned to this particular lift truck and should be used when ordering service parts or when requesting any information from your Yale industrial lift truck dealer. The serial number has eleven alpha/numeric characters and is stamped on the lift truck frame and on the capacity plate.

Model Code An explanation of the model code is located on Page B of this manual.

Truck Weight This is the approximate weight of the lift truck without a load on the forks. This weight plus the weight of the load to be moved must be considered when operating on elevated floors, elevators, etc.

Capacity Rating This rating shows the maximum capacity of this lift truck with relation to load centers and fork heights (see diagram on capacity plate). Personal injury and damage to the lift truck can occur if the capacity rating is exceeded.

SAFETY LABELS Definitions of the safety labels used on the motorized lift trucks are listed below: WARNING: Identified by an Orange Label, hazards or unsafe practices which MAY result in personal injury or death.

Sheet 1: Operating Instructions CAUTION: Identified by a Yellow Label, hazards or unsafe practices which MAY result in minor personal injury, product or property damage.

This lift truck meets all applicable mandatory requirements of ANSI 1356.1, Safety Standard for Powered Industrial Trucks, at the time of manufacture. In addition, these lift trucks are classified by Underwriters' Laboratories, Inc. for the type designation shown on the UL plate. Consult the (UL) Index of Classified Products.

Figure 1-9 -Capacity Plate The reader may find any or all of the following labels used in this publication. An understanding of their use, as follows, will aid the reader: WARNING: Directs attention to unsafe practices which could result in personal injury or death if proper precautions are not taken.

CAUTION: Directs attention to hazards or unsafe practices which may result in minor personal injury, product, or property damage if the proper precautions are not taken.

NOTE: An advisory procedure, practice, condition, etc., which is essential to emphasize.

The following Warning to the Operator is a label and must be on the lift truck: WARNING FOR YOUR SAFETY AND THE SAFETY OF OTHERS 1. Know Your Truck not operate this truck unless you have been trained and authorized to do so. Read all warnings and instructions in the Operator's Manual and on this truck, or obtain from the plant Safety Director or the local Yale representative.

2. Check your Truck-Truck should be checked daily before being placed in service. If found to be in need of repair, defective or in any way unsafe it should be reported immediately to the proper authority and the truck removed from service until it has been restored to safe operating condition.

3. Protect Yourself-Before operating truck, make sure the body belt and lanyard are securely fastened. Chain and side rails must be in position and secured.

Sheet 1: Operating Instructions 4. Keep Inside-Operate truck from designated operating position. Never place any part of your body into the mast structure or outside the truck.

5. No Riders-Carry no passengers. The operator's platform is designed for and must be used by the operator only.

6. Pickup Pallet or Platform-Be sure pallet or platform is securely attached or stable on forks. If pallet is used, position forks to the outer edges to minimize the possibility of tipping.

7. Secure Pallet or Platform-If truck is equipped with a pallet, be sure the pallet is securely clamped. If truck does not have a pallet or pallet clamp, be sure supplementary platform is securely attached. Restraining means should be used by the personnel on the pallet or supplementary platform.

8. Stabilize Your Load-Load pallet evenly within the dimensional limits of the pallet. Do not handle unstable or loosely stacked loads. Before lifting, be sure load is centered and forks are completely under load.

9. Never Overload-Do not overload truck, check nameplate for load weight and load center information.

10. Avoid Sudden Movement-Start, stop, travel, steer and brake smoothly. Use special care when traveling without load as the risk of overturn is greater.

11. Care on Ramps-Do not operate on grades when the load engaging means is elevated above 12" (300 mm). Do not turn on grades. Travel on grades with load or load engaging means upgrade.

12. Eyes Ahead-Before moving platform or truck, look forward, backward, upward and downward to be certain of a clear path of travel.

13. When Elevating-Elevate platform only to order pick, pick up or stack a load. Watch out for obstructions, especially overhead. Check clearances.

14. Watch People-Do not allow anyone to stand or pass under load or lifting mechanism.

15. Emergency Switch-All power circuits will be cut off when emergency switch is activated.

16. Shut Down Completely-Before getting off truck, neutralize travel controls, fully lower lifting mechanism. When leaving truck unattended also shut OFF power.

Failure to comply with these warnings will create an unreasonable risk of injury to yourself and others.

Sheet 1: Operating Instructions

Figure 1-10 - Serial Number, Nameplate and Label Locations Read and understand the Operating Manual attached to the lift truck. Notify your supervisor if the manual is not available.

Know your lift truck. Do not operate this lift truck unless you are trained and authorized to operate this lift truck.

Do not operate this lift truck with wet or greasy hands.

Do not operate this lift truck if it needs repair, if it is unsafe, or if it might contribute to an unsafe condition. Remove the key and report the condition to the proper authority.

Sheet 1: Operating Instructions If the lift truck becomes unsafe in any way while you are operating it, stop operating the lift truck and immediately report the matter to the proper authority.

Only specifically authorized and qualified persons should make repairs and adjustments to the lift truck.

Be certain that your lift truck is the correct fire safety type for the area in which you are working. The proper type designation for this lift truck is shown on the model code, on the nameplate, and the Underwriter's Laboratories, Inc. (UL) plate. An area of use label is required on the lift truck if it is used in areas classified as hazardous. Use only lift trucks approved for use in those areas.

If you are unsure of the classification of the area you wish to enter, ask your supervisor before entering.

Do not remove overhead guard unless specifically authorized to do so.

Make sure that fork length is at least 2/3 of load length. Carry the load flush against the lift truck.

Allow no one under or near the load or mast. Do not put any part of your body into the mast area or between the mast and lift truck.

Watch that your load does not exceed the capacity rating of the lift truck. The lift truck capacity is posted on the nameplate.

Do not handle unstable or loosely stacked loads.

Never allow anyone to ride on your lift truck and never allow anyone other than a qualified professional to operate your lift truck.

Refer to the lubrication section in this manual for the recommended hourly service intervals. Regular attention at the specified time will pay dividends in maximum efficiency and longer life of the lift truck.

OPERATOR PRE-CHECKS AND INSPECTION Before each shift, every 8 hours, it is the operator's responsibility to carry out the following checks and inspections.

Basic maintenance information and the Recommended Schedules of Maintenance are included in this manual, which is shipped with this lift truck.

For more detailed maintenance information see the Maintenance Manual for this model.

1. Make sure overhead guard, tether line/belt and all other safety devices are attached.

2. Make sure all capacity, safety and informational plates or labels are attached. This lift truck is not considered safe to use without a legible, properly filled out nameplate. Contact Yale Materials Handling Corporation or your local dealer for Yale industrial lift trucks if the nameplate is not present and legible. See label page for label and plate locations.

3. Inspect lift truck for any damage that might have occurred during the previous shift.

4. Inspect lift truck for any signs of external leaking of the battery, steering system or hydraulic system.

5. Check hydraulic hoses for leaking, chafing, cuts or reinforcement showing through the outside of the hose.

6. Make sure chains are not damaged or kinked. Check for excess slack or mistracking on the sheaves.

7. Make sure all latches are adjusted (if necessary) and fastened.

8. Operate brake, hydraulic controls and steering. Make sure all controls operate correctly and return to their proper positions. See section on Operating Controls for detailed descriptions.

9. Inspect condition of wheels and tires.

10. Inspect forks for damage. Make sure the forks are correctly attached and locked in their proper position.

11. Test horn, lights, gauges and meters. Make sure they work correctly.

12. Make sure unusual noises are investigated immediately.

Sheet 1: Operating Instructions NOTE: This Daily Check List is available for the Operator. Some items on this list may not be applicable to your truck. This convenient check list is in tablet form and can be ordered through your Yale Industrial Truck Dealer.

Form Number 944-6418-A. Daily pre-shift inspection is an OSHA requirement. We recommend that you document these inspections have been made.

OPERATOR'S DAILY CHECK LIST

OPERATING PRECAUTIONS 1. Keep hands, feet and other parts of your body inside the designated operator's compartment. Parts of your body outside the lift truck can be injured when passing obstructions.

2. Do not permit passengers to ride on the lift truck.

3. Observe and comply with instructions concerning floor loadings. Know the weight of your lift truck and load

Sheet 1: Operating Instructions combined. Lift truck weight information is located on the nameplate.

4. Travel with the load lowered. Do not elevate the load except during stacking.

5. The operator can change the direction of travel while the lift truck is moving by moving the direction control lever in the opposite direction. The lift truck will come to a stop and then, unless the control handle is released, accelerate in the opposite direction. This is called plugging.

6. Look in the direction of travel and keep a clear view of the path of travel.

7. If visibility is impaired and you must operate the lift truck in reverse, look in the direction of travel.

8. Start, stop, travel, steer and brake smoothly. Slow down for turns and on uneven or slippery surfaces that could cause lift truck to overturn or slide.

9. Watch clearances around forks. The driver must be aware that the forks can sometimes extend beyond the load. This may cause the forks to hit an object or lift another load.

10. Watch out for any obstructions, especially those overhead. Check clearances.

11. Do not run over objects on the roadway surface as lift truck stability and steering may be adversely affected.

12. When approaching cross aisles, slow down, sound horn and keep to the right side of aisle.

13. Operate lift truck under all conditions at a speed that will permit it to be brought to a stop in a safe manner.

14. These lift trucks are designed for use on smooth, hard floors with minimal grades.

15. Operate a loaded lift truck with the load upgrade. Operate an unloaded lift truck with the lifting mechanism downgrade.

16. Do not push loads with the lift truck.

17. Observe all traffic regulations, including authorized plant speed limits. Under normal traffic conditions, keep to the right. Maintain a safe distance from the lift truck ahead (approximately three lift truck lengths), and keep the lift truck under control at all times.

Warning: Watch out for pedestrians at all times. Do not drive up to anyone standing in front of an

18. object.

19. Yale lift trucks are not intended for use on public roads.

20. When leaving the lift truck unattended, lower the lifting mechanism, shut OFF power and remove key. Chock wheels if the lift truck is parked on an incline.

21. Report all accidents involving personnel, building structures and equipment to the proper authority.

22. Check all gauges and indicator lights for correct operation. Frequent reading of the instrument panel should become a habit.

23. "HANDLE WITH CARE." Avoid any abrupt moves. Be a professional.

24. Follow the Recommended Schedules of Maintenance. Maintain your lift truck for dependable and economical operation.

Sheet 2: General Truck and Lubrication Schedule GENERAL TRUCK AND LUBRICATION SCHEDULE SAFE MAINTENANCE PROCEDURES Your Yale industrial truck, as manufactured, meets all the applicable mandatory requirements of ANSI B56.1 Safety Standard for Powered Industrial Trucks.

All standard trucks conform to the Underwriters' Laboratories requirements for the Type Designation shown on the nameplate. The truck is also equipped with certain safety devices as standard equipment. For example, all high lift trucks are equipped with an operator's overhead guard.

No additions, omissions or modifications should be made that will affect compliance to the above requirements or in any way reduce the effectiveness of the safety devices.

The following instructions have been prepared for your safety and the safety of your fellow workers during maintenance operations and should be strictly followed. Carefully read and understand the maintenance procedures before attempting to repair the truck. When in doubt of any maintenance procedure, contact your local Yale industrial truck dealer.

1. Powered industrial trucks may become hazardous if maintenance is neglected. Therefore, adequate maintenance facilities, personnel and procedures should be provided.

2. The Recommended Schedules of Maintenance should be used as a guide for inspection of the truck.

3. Only qualified and authorized personnel should be permitted to maintain, repair, adjust and inspect the truck.

4. The work area should be properly ventilated. Keep shop clean and floor dry.

5. Avoid fire hazards and have fire protection equipment present. Do not use an open flame to check level of electrolyte. Do not use open pans of fuel or flammable cleaning fluids for cleaning parts.

6. Raise the lift truck only if it is on a solid level floor. Disconnect the battery. Use solid one piece blocks or other positive truck positioning devices to support the truck. Chock the wheels to prevent movement of the truck.

7. Before removing any component from the truck, such as counterweights, mast assembly, drive unit, etc., make sure that the lifting mechanism and slings are of the proper capacity and in good condition.

8. When working on the hydraulic system, be sure the truck is turned off, battery is disconnected, mast is lowered and the hydraulic pressure is relieved in hoses and tubes.

9. When necessary to work with mast in a raised position, install a safety chain to restrain moving parts. Connect moving parts to a part that does not move.

10. Brakes, steering mechanisms, control mechanisms, warning devices, guards and safety devices should be inspected regularly and maintained in a safe operating condition.

11. All parts of the lift mechanism and frame members should be carefully and regularly inspected and maintained in a safe operating condition.

12. All hydraulic systems should be regularly inspected and maintained in conformance with the maintenance schedules. Lift cylinders, valves and other similar parts should be checked to assure that "drift" has not developed to the extent that it would create a hazard.

13. Special trucks or devices designed and approved for hazardous area operation should receive special attention to ensure that maintenance preserves the original condition of the special operating features.

14. Modifications and additions which affect capacity and safe truck operation should not be performed by the customer or user without the manufacturer's prior written approval. Capacity, operation and maintenance instruction plates, tags or labels should be changed accordingly.

15. Capacity, operation and maintenance instruction plates, tags and labels should be maintained in legible condition.

16. The truck should be kept in clean condition to minimize fire hazards and facilitate detection of loose or damaged parts.

17. Checking the performance of the truck or attachments should be conducted in an authorized safe clearance

Sheet 2: General Truck and Lubrication Schedule area.

18. Always use Yale replacement parts to be sure they are interchangeable with the original parts and are of a quality equal to that provided in the original equipment.

You should also be familiar with additional maintenance safety instructions contained in the following publications: 1. ANSI B56.1 -Safety Standard for Powered Industrial Trucks This booklet can be obtained from: Society of Mechanical Engineers 345 E. 47th Street New York, NY 10017 2. ANSI/NFPA 505 -Type Designations, Area of Use, Maintenance and Operation of Powered Industrial Trucks This booklet can be obtained from: National Fire Protection Assoc.

Batterymarch Park Quincy, MA 02269 3. Code of Federal Regulations Title 29, Chapter XVII, Section 1910.178 (OSHA) Powered Industrial Trucks This booklet can be obtained from: Superintendent of Documents U.S. Government Printing Office Washington, DC

BATTERY OPERATION Batteries are rated in ampere hours and are selected to perform a specific workload within an established period of time. Changing the workload or the time period could result in excessive discharging, thus shortening battery life.

Limit discharging of battery so that specific gravities do not go below 1.140 to 1.100. If truck operation results in only partial discharges (50% or less) and specific gravities are 1.210 to 1.220 or more at the end of a shift, recharging may be deferred and the battery used for another shift providing the workload is not expected to increase.

BATTERY INSTALLATION CAUTION: The battery must fit the battery compartment correctly. Use spacers to prevent the battery from moving horizontally in the battery compartment. Make sure that the battery voltage and weight are correct as shown on the nameplate.

Remove the vent caps from each cell and determine whether the electrolyte level in all cells is at least halfway between the element protector and the bottom of the cell cover vent well. If the electrolyte is low, replace it with electrolyte of the same specific gravity as found in other cells of the battery. Replace the vent caps and give the battery a refreshing charge of three (3) to six (6) hours or continue the charge until there is no increase in specific gravity for three hydrometer readings taken at one hour intervals. The normal fully charged specific gravity is 1.280 to 1.290 at 77°F.

Figure 2-1 -Checking Specific Gravity with a Hydrometer Hydrometer readings and experience will disclose the frequency of charge intervals under these circumstances. A battery should always be recharged immediately following a complete discharge. Permanent damage may result if

Sheet 2: General Truck and Lubrication Schedule the battery is allowed to remain in a discharged condition.

Table 2-1 -Specific Gravity Temperature Corrections

Table 2-2 -Battery Specifications

WARNING: The battery must fit the battery compartment so that the battery restraint system will operate correctly.

Use the spacers designed to prevent the battery from moving more than 13mm (0.5 in) in any horizontal direction.

NOTE: Maximum tolerances are +0 and -13 mm (+0 and -0.5 in) for the size of the battery compartment. The battery specification chart shows the maximum size tolerances that will permit the battery to still fit into the battery compartment.

CAUTION: Disposal of batteries must meet local environmental regulations.

Figure 2-2 -Proper Water Level Maintain the electrolyte levels halfway between the plate protector and the bottom of the fill and vent tube but never below the plate protector or higher than the bottom of the fill and vent tube. Add only distilled or approved water.

Check electrolyte level daily, prior to charging on at least one cell and weekly on all cells.

WARNING: To prevent personal injury and unexpected battery movement, the battery must be level when it is moving. Before removing the battery to check the electrolyte levels, make sure the battery stand is on a level surface and is aligned and adjusted.

CLEANING Examine the battery case for damage and leaking. The battery can be washed off with water if dusty. Keep vent caps in place. If electrolyte has accumulated on top, wash with a neutralizing solution of soda and water (one pound of baking or commercial soda ash to one gallon of water). Follow with a rinse using clear water. The top of the battery should be kept clean and dry. Keep vent caps in place during use and charging. Remove vent caps only to observe levels, make water additions, take temperatures or take specific gravity readings with a hydrometer.

CAUTION: Keep vent plugs in the cells at all times, except when taking hydrometer readings, adjusting specific gravity and electrolyte levels, troubleshooting or reassembling a repaired cell.

Sheet 2: General Truck and Lubrication Schedule CHARGING THE BATTERY The storage battery which powers your lift truck will normally be placed on charge after each shift. If you are responsible for connecting and disconnecting the truck to the charger, follow these instructions: 1. Be sure the charger is turned off before touching the charger cable. Attempting to disconnect the cable while the charger is operating may result in damage to the cable end and injury to you.

2. If the charger is still on when you begin your shift, report this condition to your supervisor, the battery may not have received the proper charge.

3. When you are sure the charger is off, disconnect the battery from the charger. Before connecting the battery lead to the truck receptacle, make sure the truck controls are in neutral and that the connector is firmly in place.

When recharging a fully discharged battery, the starting charge rate may be 3 to 5 times higher than the finish charge rate indicated on the battery nameplate.

The charge rate should taper down to the finish charge rate by the time the battery is 85% charged and may be even lower when fully charged. High "on charge" temperatures or frequent need for water additions are indications of overcharging. Consult your Yale industrial truck dealer on specific charging problems. For complete charging instructions, refer to the manual supplied with the battery charger.

CHANGING THE BATTERY WARNING: To prevent personal injury and unexpected battery movement, the battery must be level when it is moving. Make sure the battery stand is on a level surface and is aligned and adjusted as described in the following procedure: 1. Make sure the key is in the OFF position. Disconnect the battery. Move the connector and cables so that they will not be damaged when the battery is moved.

2. Remove the battery restraint panel.

3. Align the battery stand with the battery so that the end of the stand is against the rollerframe. Adjust the capscrew legs of the battery stand so that the tops of the rollers are the same height as the bottom of the battery. Adjust all four capscrew legs of the stand so that the rollers are level. Stand on the base of the battery puller and pull the battery onto the battery stand.

WARNING: Batteries are heavy. Use care to avoid injury.

4. If the battery is lifted, use a spreader bar and crane to lift the battery from the battery stand.

WARNING: Make sure the capacity of the crane and the spreader bar is greater than the weight of the battery. The weight of the battery is normally shown on the battery case. The maximum battery weight is shown on the lift truck capacity plate. The spreader bar must not be made of metal or it must have insulated straps.

5. Before installing the battery, make sure the battery is cleaned and painted.

6. When a replacement battery is installed, make sure the battery fits the battery compartment. Use spacers to prevent the battery from moving more than 13 mm (0.5 in) in any horizontal direction.

7. Make sure the weight of the replacement battery is within the maximum and minimum weights shown on the nameplate.

8. The battery must be installed so that the battery connector will connect to the lift truck connector without pulling on the cables.

NOTE: Complete information relating to the care and maintenance of batteries can be found in the literature shipped with the battery.

Sheet 2: General Truck and Lubrication Schedule

Figure 2-3 -Changing the Battery WARNING: If a different size battery is installed in the lift truck, the battery spacers must be changed.

See the parts manual for the correct battery spacer arrangement.

WARNING: If the lift truck has been operated with a low battery, check the contactors for welded contacts before a charged battery is connected. The circuit will not reset and lift truck operation cannot be controlled if the contacts are welded. To check the contacts, see the Maintenance Manual for this truck.

NOTE: Your company, industry and government safety regulations should be reviewed to help reduce accidents and damage to equipment.

FORKS WARNING: Do not try to lift a fork without a lifting device. On some trucks the forks can weigh up to 180 kg (400 lb) each.

WARNING: Never work under a raised carriage or forks. Lower the carriage or use chains on the mast weldments and carriage so they cannot move. Make sure the moving parts are attached to a part that does not move. See SAFETY PROCEDURES WHEN WORKING NEAR THE MAST for specific instructions.

1. Check that the fork tips are aligned within 13 mm (0.5 in) of each other. Do not try to correct alignment of the fork tips by bending the forks. Use shims to align the fork tips.

2. Inspect forks for cracks and wear. Never repair damaged forks by heating or welding. Forks are made of special steel using special procedures. Replace damaged forks. Always replace forks in pairs.

3. Replace any damaged or broken parts that are used to keep the forks locked in position.

Figure 2-4 -Checking the Forks

TETHER LINE AND BELT WARNING: The tether line is specially made to lessen the shock of a fall. Do not substitute other types of rope.

1. Inspect the tether line for wear, cuts or damage. Inspect the clips for cracks and proper operation.

2. Inspect the belt for cracks, cuts or wear. The operator must fasten the belt snugly with the "D" ring in the center of the back.

PALLET CLAMP

Sheet 2: General Truck and Lubrication Schedule Check for correct operation of the pallet clamp. Put an empty pallet on the forks. With the forks raised so that the pallet is supported by the forks, stand on the corners of the pallet farthest from the operator's platform. Some movement may occur, but the board under the opposite fork must not raise enough to contact the fork.

HOW TO PUT A LIFT TRUCK ON BLOCKS WARNING: The lift truck must be put on blocks for some types of maintenance and repair. The removal of the following assemblies will cause large changes in the center of gravity:S mast, drive axle and battery.

WARNING: Put the lift truck on blocks only if the surface is solid, even and level. Make sure that any blocks used to support the lift truck are solid, one piece units. Put blocks in front and back of the tires to prevent movement of the truck.

How to Raise the Drive/Steer Tire 1. Put a block on each side (front and back) of the load wheels to prevent movement of the lift truck.

2. Use a special low clearance hydraulic jack under the front frame to raise the drive/steer tire. Another lift truck can also be used to raise the lift truck. Make sure that the jack or other lift truck has a capacity of at least 2/3 the total weight of the lift truck as shown on the nameplate.

3. Raise the lift truck only enough to suspend the drive/steer tire. Install blocks under the front of the frame to support the lift truck.

How to Raise the Load Wheels 1. Release the brake pedal to apply the brake. Put blocks on both sides (front and back) of the drive/steer tire to prevent movement of the lift truck.

2. Use an overhead crane and web sling under the outriggers at the mast, to raise the load wheels. Another lift truck can also be used to raise the outriggers. Make sure that the crane and sling or other lift truck has a capacity of at least 2/3 the total weight of the lift truck as shown on the nameplate.

3. Raise the outriggers only enough to suspend the wheels. Install blocks under the outriggers at the front of the wheels to support the lift truck.

Sheet 2: General Truck and Lubrication Schedule

Figure 2-5 -How to Put the Lift Truck on Blocks

LUBRICATION INSTRUCTIONS WARNING: Yale industrial trucks are equipped with certain safety devices as standard equipment; for example: overhead guards, tether line and belt, mast screens, etc. If for any reason these safety devices are removed when the truck is being serviced, adjusted, repaired or overhauled, these safety devices must be properly reinstalled before testing or operation of the truck. Failure to comply with this warning could result in serious injury to the mechanic and/or the operator.

CAUTION: Never use steam to clean the electronic control or electrical parts. In dusty areas, use low pressure air to blow the dust off the control. In oily or greasy areas, use a mild solution of detergent and water, or denatured alcohol to wash the control. Then blow the control completely dry with low pressure air.

WARNING: The service intervals referred to in these lubrication and maintenance instructions are based on normal operating conditions. If you have a light duty or low operating hour application, the maximum service interval should not exceed 90 days. If the vehicle is operated in areas of high contamination such as dust, corrosive vapors, etc., the service interval must be decreased from the recommended hours. Have a qualified Yale mechanic inspect the truck and repair any problems.

The following maintenance instructions are for standard models. Trucks used for special applications may be equipped with extra lubrication fittings, covers, special oils, etc. Consult your nearest authorized Yale industrial truck dealer when servicing these models.

Refer to both the Recommended Schedules of Maintenance and these Lubrication Instructions when inspecting, lubricating and servicing these models. Read and observe all safety and operational precautions described in this manual before performing any work on this truck. Refer to the appropriate charts in this section for the oils and grease that are recommended for use on these models.

EVERY 8 HOURS Perform all 8 hour safety and operational checks as described in the Recommended Schedules of Maintenance

Sheet 2: General Truck and Lubrication Schedule located in this section. Hydraulic oil and battery levels should be at their full marks. Add recommended fluids and oils as required. A certain amount of water loss in battery cells is normal. Always replace water at the end of a charge.

Use approved tap or distilled water.

EVERY 350 HOURS Apply lithium base, multi-purpose No. 2 grease with a high pressure gun to the following fittings. Clean lube fittings before and after lubricating.

Location of Lube Fittings

No. of Fittings

1. Master Drive Unit Bearing . . . . . . . . . . . . . . . . . . . . . . . 2 2. Platform Thrust Rollers -Platform . . . . . . . . . . . . . . . . . 4 Apply lithium base, multi-purpose No. 2 grease to the following surfaces: 3. Mast Sliding Surfaces Apply engine oil (SAE 30) to the following friction points: 4. Hose and Wire Sheaves -Mast Take-up 5. Drive Unit Compartment Door Hinges 6. Pallet Clamp and Linkage -Elevate Platform 7. Side Rails -(pivoting option) 8. Steering Spinner Knob 9. Battery Retainers 10. Lift Chains -Wipe off all old oil using a clean cloth, then use compressed air to blow off chains. With a clean brush, apply SAE 30 weight oil to the full length of chain. Oil must penetrate chain joints.

11. Drive Unit Steer Chains -Refer to Step 10.

12. Drive Wheel Lug Nuts 13. Load Wheel Axle Bolts 14. Hydraulic Oil Level - The sight gauge is visible through a hole in the door of the drive unit compartment. The surface of the oil is at the center of the window of the sight gauge when the hydraulic tank is filled to the correct level. The platform must be lowered for a correct indication. If the oil is above or below the window of the sight gauge, open the door to check the level. Add hydraulic oil, if necessary. DO NOT OVERFILL.

EVERY 2000 HOURS 15. Hydraulic Oil Filter - Remove Hydraulic Oil Cover Plate Assembly to access filter. Replace the hydraulic oil filter, located in the drive unit compartment, at each oil change.

16. Hydraulic System -There is no drain plug in the hydraulic tank. The hydraulic tank is drained at the supply hose.

Put a shallow pan with a capacity equal to the hydraulic system of the truck (hydraulic tank capacity 32 litres, 8.5 gallons) under the end of the hose. Disconnect the hose and drain the oil. Pour the oil into a suitable container and discard in accordance with local regulations. Clean the hydraulic tank with solvent and dry with compressed air. Connect the hose to the tube and tighten the hose clamp. Fill the tank with hydraulic oil (hydraulic tank capacity 32 litres, 8.5 gallons). Raise and lower the mast to expel air from hydraulic system.

Sheet 2: General Truck and Lubrication Schedule

Figure 2-6 -Lubrication Locations YALE WARRANTY INFORMATION A Yale Warranty Statement is provided with each new Yale industrial truck. To maintain your Yale Warranty in good standing you must follow the Recommended Schedules of Maintenance and perform the daily operational and safety checks and maintenance functions described in this manual.

If you require a warranty repair you must contact your Yale industrial truck dealer for warranty service during the periods outlined in the Warranty Statement. Your Yale industrial truck dealer has complete details on which components are covered and the types of repairs that are warrantable. When in doubt about your warranty coverage, be sure to contact your Yale industrial truck dealer. If you have a warranty problem that cannot be resolved with your Yale industrial truck dealer, you may request a review of your problem by contacting the Yale Regional Service Representative.

All new Yale trucks will be shipped with an Operating Manual. Standard Parts Manuals, Special Parts Manuals and Maintenance Manuals are also available from your Yale industrial truck dealer for a nominal charge.

For the optimum in professional repair and maintenance, we recommend your Yale industrial truck dealer's factory trained mechanics for Yale service and a Yale Maintenance Agreement.

RECOMMENDED SCHEDULES OF MAINTENANCE (ALL MODELS) Although the following Recommended Schedules of Maintenance are intended for use with all Electric Narrow Aisle lift truck models, not all models are equipped with all the items listed in this schedule.

Be certain this schedule is read thoroughly and all operations are followed. If in doubt of any procedure or component to be inspected, adjusted and lubricated, or if the truck is specially equipped and used for special applications, consult your nearest authorized Yale industrial truck dealer for assistance.

THE OCCUPATIONAL SAFETY AND HEALTH ACT (OSHA) REQUIRES THAT THE USER EXAMINE THE TRUCK BEFORE EACH SHIFT TO BE SURE IT IS IN SAFE WORKING ORDER.

Sheet 2: General Truck and Lubrication Schedule

NOTE: The following inspections and necessary corrections are the responsibility of the user.

Sheet 2: General Truck and Lubrication Schedule

Sheet 2: General Truck and Lubrication Schedule

Sheet 2: General Truck and Lubrication Schedule

1. Tires -Condition affects stability, safety and load capacity that can be handled safely.

2. Use Magnaglo or equivalent Fatigue Crack Detector to test forks. Refer to Service News Bulletin SE-643 for Procedure on Field Testing Load Forks. The Bulletin also defines minimum acceptable fork tine thickness due to wear.

3. With the mast vertical and with a rated load at 609.6 mm (24in) load center, check lift cylinder drift. Lift drift must not exceed 25.4 mm (1 .0 in) in 2 minutes, oil at 26°C (79°F). Refer to Service Bulletin SE-1077 for Procedure to Measure Hydraulic Drift.

4. With a rated load at 609.6 mm (24 in) load center, check tilt cylinder, if equipped, for drift. Tilt drift must not exceed 25.4 mm (1 .0 in) in 2 minutes, oil at 26°C (79°F). Refer to Service Bulletin SE-1077 for procedure to measure hydraulic drift.

5. The presence of hydraulic fluid on cylinder rods and fittings does not necessarily indicate a leak.

6. Recycle all waste oils.

CAUTION: Disposal of lubricants and fluids must meet local environmental regulations.

To obtain more information on the above reference Service Bulletin, contact your nearest authorized Yale industrial truck dealer.

HYDRAULIC OILS

Sheet 2: General Truck and Lubrication Schedule

GEAR OILS

Sheet 2: General Truck and Lubrication Schedule

GREASE

Sheet 2: General Truck and Lubrication Schedule

ANTI-SEIZE LUBRICATING COMPOUND

TIRES AND WHEELS 1. Check the tires for damage. Inspect the tread and remove any objects that will cause damage.

2. Smooth any cuts or tears to prevent further damage. Check for bent or damaged rims. Check for loose or missing parts. Remove any wire, straps or other material that may have wrapped around the axle.

Sheet 2: General Truck and Lubrication Schedule

Figure 2-7 -Inspecting Tires How to Change the Drive/Steer Tire Standard tire sizes are listed for drive/steer and load wheels. For trucks equipped with special tires consult your nearest authorized Yale industrial truck dealer.

Raise the rear of the lift truck as described in How to Put a Lift Truck on Blocks. Remove the wheel nuts that fasten the drive/ steer wheel to the hub. Slide the wheel out from under the lift truck. Use the reverse procedure to install the wheel. Tighten the wheel nuts to 136 Nm (100 Ibf. ft.) torque after installation.

CAUTION: If the wheels have been removed and installed, check all wheel nuts after 2 to 5 hours of operation.

Tighten the nuts in a cross pattern to 136 Nm (100 Ibf. ft.) torque value. When the nuts stay tight for eight hours, the interval for checking the torque can be extended to 350 hours.

To change the drive tire, the wheel must be pressed out of the rim. The correct tools, equipment and press ring must be used for each size wheel. A press that has a capacity of approximately 36,000 kg (80,000 lb) is required to press the wheel out of the rim. Tires should be changed by authorized personnel that have the proper tools, equipment and experience.

Figure 2-8 -Position Tire on Wheel How to Change the Load Wheels WARNING: For correct operation of the wire guidance system, all load wheels must always be replaced at the same time.

Raise the load wheels as described in How to Put a Lift Truck on Blocks (How to Raise the Load Wheels). For easier installation, remove and install one load wheel at a time.

The load wheel bearings are prelubricated, double sealed ball bearings. They do not require lubrication for the life of the bearing. No shimming is required.

Sheet 2: General Truck and Lubrication Schedule

Table 2-3 -Tires and Wheels HOW TO MOVE A DISABLED LIFT TRUCK WARNING: Use extra care when towing a lift truck if there is a problem with any of the following: 1. Brakes do not operate correctly.

2. Steering does not operate correctly.

3. Tires are damaged.

4. Traction conditions are bad.

5. If the lift truck must be towed on a steep grade.

Poor traction can cause the disabled lift truck or towing vehicle to slide. Steep grades will increase the required brake effort.

Remember! There may be problems with more than one of the above areas of the truck. Do not tow the lift truck if you have not identified all problem areas.

HOW TO TOW THE LIFT TRUCK WARNING: If there is no electrical power the brakes will be applied and the steering motor will not operate. The lift truck cannot be steered if the steering motor does not operate. DO NOT tow the lift truck if there is no electrical power.

1. The towed lift truck must have an operator.

2. Depress the brake pedal during towing to release the brake.

3. Tow the lift truck slowly.

4. Raise the forks approximately 12 inches (30 cm) from the surface. Install a chain to prevent the mast from moving.

5. If another lift truck is used to tow the disabled lift truck, that lift truck must have an equal or larger capacity than the disabled lift truck. Install an approximate half capacity load on the forks of the lift truck that is being used to tow the disabled lift truck. This half capacity load will increase the traction of the lift truck. Keep the load as low as possible.

If the lift truck must be moved without electrical power, the brake can be manually released. There are three holes with 1/4-20 UNC threads in the back plate. Install capscrews in the holes. Use the capscrews to push the armature plate away from the friction disc.

WARNING: If the brake has been manually released, put a "DO NOT OPERATE" tag on the steering wheel.

Never lift a disabled lift truck unless the lift truck must be moved and cannot be towed. The lift truck used for lifting the disabled truck must have a rated capacity equal to or greater than the weight of the disabled lift truck. The capacity must be for a load center equal to half the width of the disabled lift truck. See the nameplate of the disabled lift truck for the approximate total weight. The forks must extend the full width of the disabled lift truck. Center the weight of the disabled lift truck on the forks and be careful not to damage the underside of the lift truck.

PRECAUTIONS FOR TRUCKS IN STORAGE Complications can arise as a result of improper handling of trucks during periods of storage. The main areas of concern are the: electric motors, hydraulic components and electric truck batteries.

Before placing truck in storage, choose an area which is clean, dry and free from airborne contaminants.

Sheet 2: General Truck and Lubrication Schedule When parking the truck, chock the wheels. The forks should be fully lowered. For safety and increased usable floor area remove the forks and tag them with the truck serial number. Coat all exposed portions of cylinder rods with fresh high grade SAE 30 or 40 weight engine oil.

Electric trucks should be stored without batteries. Therefore you will have to provide a fully charged battery for the period of this exercise.

All hydraulic cylinders should be cycled several times each month to keep the seals active and to coat the interior walls with oil. Actuate each cylinder, in both directions, until the stops are reached. With the power OFF, actuate each control button to relieve hydraulic pressure.

Prior to operating the truck, make a visual inspection for any leaks or signs of deterioration. Check the fluid level in the hydraulic tank and brake master cylinder. Take corrective action if necessary.

Operate the truck for a short period of time each month. Electric drive motors must be exercised to keep them free of rust and contamination caused by condensation built up over periods of inactivity. Operate the truck with the motor at its normal temperature for at least five minutes.

When the truck is returned to service, it should be given the 350-hour inspection shown in the Recommended Schedules of Maintenance found in this manual.

PRECAUTIONS FOR BATTERIES IN STORAGE Batteries should be placed on a wooden pallet and stored in a dry, moderately cool area. Lead acid batteries will slowly "self discharge" over a period of time due to their chemical make-up. If the self discharge is left uncontrolled, excessive sulfating can occur which is difficult to reduce and may damage the plates.

A discharged battery with a specific gravity of 1.100 will freeze at + 18 °F. A fully charged battery with a specific gravity of 1.280 will freeze at -87° F This "self discharge" is due to a chemical reaction, therefore, that chemical reaction can be accelerated by heat resulting in a more rapid "self discharge". The rate of discharge can amount to an average of about 0.001 point drop in specific gravity per day.

The following procedure should be followed when placing a battery in storage or when not in operation for more than 30 days. a. Give equalizing charge prior to placing new batteries in storage. Used batteries are to be fully charged and allowed to balance for approximately three more hours. b. Neutralize and clean the battery. Clean with a solution of 16 ounces of baking soda ash in one (1) gallon of water. c.

Store in a cool, dry location.

d. Check each cell in the battery at least once every 30 days and boost charge when specific gravity falls below 1.240. e. Protect batteries from ambient contamination.

If a greasy film forms on the top of a battery, it is acid and must be neutralized with a solution of 16 ounces of baking soda ash in one (1) gallon of water.

FASTENERS INTRODUCTION Threaded fasteners like bolts, nuts, capscrews, and studs are made to specifications that describe the mechanical strength and hardness of the fastener. A fastener used in a design application is selected according to its specifications. Yale Materials Handling Corporation buys parts from many countries. Parts that are purchased must be to Yale standards. There are several standards used by these countries in the manufacture of threaded fasteners. Many of these fasteners are similar, but cannot be used as a direct replacement. To make sure that you have the correct fastener, order fasteners and parts through the Yale Parts Distribution Center, Danville, IL. Service persons must use replacement fasteners that have the same specifications. Fasteners made to each specification have identification marks for that specification. This specification is commonly called "Grade" for SAE standards and "property class" for metric standards. This section describes the identification of some common fasteners.

Sheet 2: General Truck and Lubrication Schedule The metric system used by Yale Materials Handling Corporation is described as SI (Le Systeme d'Unites orthe International System of Units, also called SI in all languages). The SI system of measurement is described in ISO Standard 1000, 1973. A conversion table of common measurements is shown in Table 2-12.

THREADS, NOMENCLATURE The thread design is specified by a series of numbers and letters for inch and metric fasteners. See Figure 2-9. The diameter of the shank of the fastener is shown first in the series [M12 = 12 mm, M20 = 20 mm (1/2 = 1/2 inch, 3/4 = 3/4 inch)].

The length of the shank is often indicated as part of the description of a fastener. This length is shown in inches for inch fasteners and in millimeters for metric fasteners.

The number of threads per inch for inch fasteners may either be shown as UNC (Unified National Coarse) or UNF (Unified National Fine). Metric fasteners show the thread pitch.

A capscrew will have the following description: Table 2-4 -Capscrew Description

Figure 2-9 -Thread Design

STRENGTH IDENTIFICATION The most common property classes for metric fasteners are 8.8 and 10.9. The property class is marked with a number on the head of the capscrew or on a nut. Property classes less than 8.8 are often not marked. Grades for inch bolts go from 2 to 8. Grade 2 fasteners normally do not have any marks. The following tables show the marks that identify the grades and property classes for different fasteners.

CAUTION: When fasteners must be replaced, the new fasteners must be of the same strength or greater than the original fasteners. The new fasteners must also be the correct size.

NOTE: Identification marks are according to bolt strength. The higher the number or the increase in the number of marks indicates increased bolt strength.

Table 2-5 - Bolts and Screws

Sheet 2: General Truck and Lubrication Schedule

Table 2-5 -Bolts and Screws Table 2-6 Studs and Nuts

Sheet 2: General Truck and Lubrication Schedule

Table 2-6 -Studs and Nuts Table2.7 Torque Nuts

Sheet 2: General Truck and Lubrication Schedule

Table 2-7 -Torque Nuts Table 2-8 Torque Nuts with Nylon Inserts

Sheet 2: General Truck and Lubrication Schedule

Table 2-8 -Torque Nuts with Nylon Inserts Table 2-9 - General Guide to Torque Values

Sheet 2: General Truck and Lubrication Schedule

Table 2-9 -General Guide to Torque Values Table 2-10 - General Guide to Torque Values

Sheet 2: General Truck and Lubrication Schedule

Table 2-10 -General Guide to Torque Values Table 2-11 -Recommended Maximum Torque Values for Hydraulic Fittings*

Sheet 2: General Truck and Lubrication Schedule

Table 2-11 -Recommended Maximum Torque Values for Hydraulic Fittings* Table 2-12 -Conversion Table for Metric and English Units

Sheet 2: General Truck and Lubrication Schedule

Sheet 3: Electrical System

ELECTRICAL SYSTEM GENERAL This section describes the electrical system used on the OS30EB lift truck. Procedures are outlined for the maintenance, adjustments and repairs that may be required when servicing this truck. The electric brake is outlined in Section 5 and the control module and electrical components of the steering system are covered in Section 6 of this manual.

The drive control of the OS30EB lift truck is a Curtis Transistor Motor Controller, also known as a MOSFET System.

WARNING: Before performing any adjustments, service procedures, or parts replacements that require physical contact with electrical components or wiring, DISCONNECT THE BATTERY, DISCHARGE THE INTERNAL CAPACITOR, AND JACK THE DRIVE WHEEL UP OFF THE FLOOR. Properly block the truck.

The capacitor in the transistor controller can hold an electrical charge after the battery is disconnected. To prevent electrical shock and injury, discharge the capacitor before inspecting or repairing components in the drive unit compartment. Wear safety glasses. To discharge the capacitor, first disconnect the battery. Then connect an insulated jumper wire between the B+ and B-terminals (Figure 3-11) of the transistor controller.

Figure 3-1 -Drive Unit Compartment

TRANSISTOR MOTOR CONTROLLER This section describes the operation , checks, repairs and troubleshooting of the Curtis PMC 1204X series motor controller. This transistor motor controller is used to control the operation of some 12 or 24 volt electric lift trucks.

Sheet 3: Electrical System

Figure 3-2 - Transistor Motor Controller The description of the current flow in the electrical circuits in this section uses the "Conventional Theory of Current Flow". This theory describes the current as flowing from positive to negative. An electric lift truck uses a two-wire electrical system. There is no common ground through the frame. Both the positive supply and the negative return currents flow through wires and cables. There must be a minimum resistance of 50,000 ohms between the electrical circuits and the frame of the lift truck.

The controller for the traction system uses digital logic. Digital logic uses transistor to operate like very fast switches.

The transistors are controlled by electrical gate pulse. Electrical noise is high voltage pulses caused by momentarily operating other electrical devices. Digital logic can not understand the difference between control pulses and electrical noise. Filter capacitors are connected between the B+ and B-terminals in the controller to prevent electrical noise from entering the logic and causing errors.

The logic of the controller also checks the following functions: a. Checks the temperature and gives both low and high temperature thermal protection to the controller. b. Electrically checks that an operator follows the correct starting sequence to help prevent unexpected operation. This function is called "Static-Return-To-Off" (SRO). c.

Electrically checks the traction circuit for malfunctions, This function prevents lift truck operation if a failure is sensed.

d. Checks the current in the motor circuit and automatically decreases the motor voltage to reduce the current and prevent damage. The plugging circuit is also controlled for smoother operation.

Additional information showing how the motor controller is electrically connected in the lift truck is shown on the Wiring Diagrams and Schematics located at the rear of this section.

OPERATION A motor controller for an electric lift truck must give a fine speed control to the traction motor by making a variation in the applied voltage. This controller uses solid-state electronic devices to permit efficient control of the applied voltage.

A motor controller must also generate a high current flow in the traction motor while keeping a low current draw from the battery. A battery is less efficient at a high current draw. A battery will not give all its electrical power at a high current draw. The traction motor is a series wound motor that generates torque. This torque is proportional to the current moving through the motor. The speed of the motor is controlled only by the mechanical load connected to the motor. The motor will accelerate until the mechanical load compares equally to the torque. If the current through the motor is increased, the torque will increase. The increased torque will give a higher speed with the same mechanical load.

Sheet 3: Electrical System The two functions look like a problem of opposite needs. How a solid-state electronic controller balances those needs with efficiency is described in this section.

MOTOR CONTROLLER This motor controller controls the speed of the traction motor. The direction of rotation of the motor is controlled by the Forward/Reverse switch and contactors. See Figure 3-3, Figure 3-4 and Figure 3-5. The controller is sealed in an aluminum case and has no parts that can be repaired or replaced. The complete unit must be replaced if correct troubleshooting methods show that the unit is defective.

The controller uses external contactors to control the direction of rotation of the traction motor. Contactors are electrical switches that use an electromagnet to operate the power contacts of the switch. A small electric signal is used to energize the electromagnet to close the power contacts and control the large current flow needed for the motor circuit. The electromagnetic field in the coil moves the armature against spring pressure to close the power contacts. When the coil is de-energized, the spring pressure moves the armature and opens the contacts. When a spring holds the contacts of a switch open, the switch is called normally open (NO). If the switch spring holds the contacts of switch closed, the switch is called normally closed (NC).

There are two contactor that control the direction of rotation of the traction motor. Each direction contactor has two sets of contacts on the same plunger assembly. Each contactor has a set of NO contacts and a set of NC contacts.

When one set of contacts is closed, the other set of contacts must be open. This arrangement prevents a wrong sequence of closed contacts that could cause a short-circuit. This arrangement of contactors also permits current flow through the motor field in either direction. See Figure 3-4 and Figure 3-5. One set of contacts causes the motor armature to rotate in one direction. The other set of contacts causes the motor armature to rotate in the opposite direction. Other contactors used for control functions on the lift truck only have one set of contacts because a forward and reverse operation is not required. An example is the hydraulic pump motor contactor.

Contactors are used to energize and de-energize motors, but cannot control the speed. The transistor motor controller applies battery voltage in short, fast pulses to a DC motor to control the speed. How this circuit controls the speed of a motor with pulses is described in this section.

The direction and speed control operates the FWD/REV switch to energize the direction contactor. The control also supplies the speed input to the motor controller.

1.

2.

3.

4.

5.

6.

BATTERY TRACTION MOTOR ARMATURE TRACTION MOTOR FIELD REVERSE CONTACTOR CONTACTS FORWARD CONTACTOR CONTACTS FETs SWITCH Figure 3-3 -Basic Traction Motor Circuit

BASIC CONTROLLER OPERATION This transistor motor controller has a power section and a logic section with solid-state electronic circuits that control the operation of a DC motor. The speed of DC motors is controlled by the average applied voltage. The higher the average applied voltage, the faster the motor will rotate. If a switch is put in the traction motor circuit (see Figure 3-3), and the switch is changed to OFF and ON quickly (see Figure 3-7), the traction motor will rotate. As the ON time increases, the speed of the motor increases. As the OFF time increases, the speed of the motor decreases, The speed of the motor can be controlled using this principle.

Sheet 3: Electrical System

Figure 3-4 -Current Flow through The Field In The FORWARD Direction This controller uses and electronic device called a Field Effect Transistor (FET) to generate the rapid ON and OFF pulse times. It has no moving parts. The FETs are turned on and off by the logic circuits in the controller to act as the switch. Several power FETs are connected in parallel to carry the necessary motor current.

Figure 3-5 -Current Flow through The Field In The REVERSE Direction

THE FIELD EFFECT TRANSISTOR (FET) A FET is a solid-state device that operates like a very fast switch. Transistors are electronic devices that permit electricity to flow in only one direction. See Figure 3-6. A transistor permits electricity to flow easily from the anode to the cathode. A FET is a transistor that has an additional element called a gate.

Sheet 3: Electrical System

Figure 3-6 -Transistor Control 1. BATTERY 2. TRACTION MOTOR 3. FETs SWITCH 4. FET CATHODE 5. FET ANODE 6. FET GATE 7. POSITIVE SUPPLY THROUGH MOTOR 8. NEGATIVE GATE SIGNAL 9. NO GATE SIGNAL 10. NO POSITIVE SUPPLY (FETs OPEN) A FET will only permit current flow when there is a negative voltage of the source, a positive voltage at the drain AND a positive signal voltage applied to the gate. A FET will permit electricity to flow from the anode to the cathode as long as there is the signal voltage at the gate. The FET ON time is the same as the gate pulse ON time as shown in Figure 3-7. The FET stops conducting when the signal voltage is removed from the gate.

When FETs are used as a switch: a. The FETs are ON when electric current flows through them (gate signal). b. The FETS are OFF when electric current cannot flow through them (no gate signal).

A MOTOR CIRCUIT THAT OPERATES WITH PULSES Figure 3-6 is part of a schematic that shows the controller and FETs in a traction circuit. When a signal is applied to the gate of the FETs, the FETs are ON and current flows from the battery through the motor.

When the gate signal is removed, the FETs are changed to OFF. The battery voltage is applied to the motor in

Sheet 3: Electrical System pulses. The pulses of energy through the FETs to the motor are very fast (15,000 on/off cycles per second). The motor cannot follow each pulse, but the motor runs smoothly on the average voltage generated by the ON and OFF times. Figure 3-7 shows the average motor voltage applied to the traction motor. The length of the ON TIME of the pulses changes the average motor voltage. As the ON TIME of each pulse increases (OFF TIME decreases), the average motor voltage increases. This change in the ratio of ON TIME to OFF TIME of the pulses is called pulse width modulation.

The control circuit has an oscillator and a pulse width modulator. The oscillator generates a saw tooth waveform at a constant frequency of 15,000 cycles per second (15 kHz). The pulse width modulator uses this saw tooth waveform to generate a pulse output that can be smoothly changed from a full ON to a full OFF condition. This pulse output is used by the gate driver circuit to turn the FETs on and off. The pulse width modulator controls the ON and OFF times of the FETs through the gate driver. The ratio of ON TIME to OFF TIME sets the average motor voltage and the motor speed, The accelerator potentiometer, at the speed control of the lift truck, produces a voltage that changes as the operator sets the speed of operation. This voltage is an input to the controller and the pulse width modulator. As the voltage changes with the selected speed, a direct change in the ratio of FET ON TI ME to FET OFF TIME also occurs. The voltage for maximum speed changes the ratio to pulses with the maximum ON TIME, to produce a maximum average motor voltage. See Figure 3-7. The pulse rate (15 kHz) stays the same for all speeds.

Figure 3-7 -Average Motor Voltage

INDUCTION CURRENT FROM THE MOTOR

Sheet 3: Electrical System When a DC motor is controlled by a pulsed circuit, the magnetic field in the armature and field windings is continuously increasing and decreasing. The fields increase when voltage is applied (ON TIME) and decreases when the voltage is removed (OFF TIME). The voltage causes an increasing current flow through the windings to make the increasing magnetic field. When the voltage is removed, the decreasing magnetic field causes current to flow in the same direction through the windings. See Figure 3-8. This increase and decrease of the magnetic field is lost energy for doing work unless the controller is designed to use this energy. A Flyback Diode (sometimes called a Freewheel Diode) is in the controller circuit for this purpose.

Figure 3-8 - Inductance The Flyback Diode permits the current, from the decreasing magnetic field, to flow through the field and armature again to do work. The torque of a series DC motor is directly proportional to the amount of current flow through it. At slower speeds, the OFF times are longer. When the FETs are OFF, the decreasing magnetic field generates a voltage and current in the motor. This current is often called the "flyback current". The Flyback Diode permits the current to flow through the field and armature again to do work. At slower speeds, the motor current is part battery current and part 'flyback current'. There is less battery current used for the specific torque requirement. High current draw from the battery is to be avoided, if possible, because it is less efficient. At higher speeds, the OFF time is less, so that less induction current ("flyback current') is generated. Most of the motor current must come from the battery at higher speeds. However, the torque and current requirements are also usually less.

The graph in Figure 3-9 shows the typical induction current during equal ON and OFF times of the FETs.

Sheet 3: Electrical System

Figure 3-9 -Induction Motor Current 1.

2.

3.

4.

5.

6.

BATTERY ARM MOTOR ARMATURE MOTOR FIELD CONTROLLER FETs (NOT "ON") FLYBACK DIODE NA00404

PLUGGING Plugging is a method of stopping an electric lift truck by changing the direction of current flow within the field of the traction motor. The Direction/Speed control must be moved for travel in the opposite direction of present travel.

Plugging is actuated when reversing occurs at the direction switch. The direction contactors will change to the opposite positions and reverse the current flow from the battery through the motor field. The motion of the lift truck drives the traction motor armature to make the motor operate as a generator. This additional "generator" current (armature current) adds to the current flow through the field to reverse the motor at an even faster rate. Unless the control circuit provides away to slow this change of direction, the lift truck will stop very quickly. The plug diode in the control circuit prevents the lift truck from stopping too quickly. While the motor is acting as a generator, the plug diode prevents this "generator current" from adding to the field current. The control circuit lets all of the plugging current flow from the armature through the plug diode, then flow with the battery current through the armature again.

This reduces the effect of the induction current.

During plugging the pulse rate is also reduced from 15 kHz to 1 kHz. The controller regulates the pulse widths of the pulses to the motor field for the correct amount of plugging. The accelerator circuit is also set to a low speed so the normal acceleration in the opposite direction will occur. The plugging adjustment on the controller changes the amount of motor field current allowed. The plugging adjustment can be changed as needed for application.

Sheet 3: Electrical System

1.

2.

3.

4.

5.

BATTERY ARM MOTOR ARMATURE MOTOR FIELD CONTROLLER PLUG DIODE Figure 3-10 -Plugging Current Circuit

CONTROL CIRCUIT The control circuit has operator inputs from the key and brake switches (terminal 1) as well as the accelerator potentiometer (terminals 2 & 3). The circuit also has internal inputs from the power circuit for thermal protection, plugging sensing, low voltage protection and motor current (current limit). The control circuit uses these inputs to regulate the ON TI ME pulses to the FETs for speed control, current limit and plugging strength.

STATIC-RETURN-TO-OFF (SRO) FUNCTION The control circuit includes a function to prevent the operation of the lift truck if the starting sequence is not correct.

This function uses the inputs to the control circuit to make sure the operator is ready to operate the controls. The starting sequence follows: a. Turn the key switch to the ON position. The key switch supplies the battery voltage to the brake switch. b. Close the brake switch. Battery voltage is now supplied to the control circuit. c. Rotate the Direction/Speed control in the desired direction of travel to select travel direction and speed.

If step c is done before both steps a and b are complete, the lift truck will not move in either direction. The control circuit must get battery voltage through both the key and brake switches before it gets a speed signal from the accelerator potentiometer. If the starting sequence is not correct, the control circuit will not send a gate pulse to the FETs for traction motor current.

The SRO function also prevents the lift truck from going to full speed operation because of a malfunction in the accelerator circuit. A closed circuit in the accelerator circuit normally senses a full speed signal by the controller. If this malfunction exists, the SRO function will prevent the start of traction pulses. If the malfunction occurs during normal operation, the control circuit senses an accelerator potentiometer input of more than 7000 ohms (open circuit) and stops traction pulses. The circuit will return to normal operation after the malfunction is repaired.

THERMAL PROTECTION FUNCTION There is a sensor to sense the heat within the controller housing. If the controller gets too hot or too cold for correct operation, the control circuit will reduce the ON TIME of the pulses to decrease the current to protect the controller.

The lift truck will still operate at a slower speed to permit it to be moved to a location out of the work area. The controller can then return to a normal operating temperature.

Sheet 3: Electrical System LOW VOLTAGE PROTECTION FUNCTION This function protects the controller and the battery. The controller will not operate correctly if there is not a minimum voltage from the battery. The battery current drain increases as the battery voltage decreases. Too large a battery drain will damage the battery. If the battery voltage is low, the control circuit will decrease the ON TIME of the pulses to decrease the current drain. The battery can still operate the lift truck to move it for battery charging or replacement.

POWER CIRCUIT The power circuit is controlled by the control circuit. The complete power circuit is inside the controller and has the following parts: • • • • •

The Field Effect Transistors The Freewheel Diode The Plug Diode The Filter Capacitors The Temperature Sensor

The parts in the power circuit cannot be replaced by users. Cables connect the battery and traction motor to the power circuit at the controller power terminals "B + ", "A2", "M-" and " B-". All of the traction motor current flows through the power circuit of the controller.

AUXILIARY SECTION The auxiliary circuit is also contained within the controller. The components that make up the auxiliary section are not replaceable.

The auxiliary section accepts all user control inputs, provides outputs and monitors and controls the logic and power section of the controller. A 1 2V regulator powered by B + provides the power for all the auxiliary section circuits.

The controlled inputs are: • Key switch and interlocks • Directional switches • Static return to off The output provided is: • Forward/Reverse contactors Controllers with SRO (Static return to off) must be properly sequenced to enable the controller and allow it to operate. The key switch input must be turned on before the forward or reverse input is engaged to allow the control logic to turn on the controller. If the key switch input is turned on at the same time or later than the forward or reverse input, the controller will not turn on.

A proper turn-on sequence will enable the logic section of the controller, allowing the controller to respond to the accelerator input. This will turn on the forward/reverse contactor driver and provide the proper output to the selected directional contactor. If a fault is detected, or if the logic boards power supply is out of range, the controller and the contactor driver will not be allowed to operate even if a valid turn on sequence is initiated.

The bypass contact driver will turn on the bypass contactor when the accelerator demand level reaches 90 % for at least one second. The contactor will turn off instantly when the accelerator demand is less than 90 %.

Both the forward/reverse and bypass contactor drivers are protected against short circuits.

CHECKS, ADJUSTMENTS, AND REPAIRS There are several checks that can be made that check for correct operation of the system. There are only three external adjustments and no internal adjustments for the transistor controller.

NOTE: These checks require voltmeter with a meter movement. Most digital meters will not operate correctly for some of these checks. Specific checks require additional equipment.

WARNING: Disconnect the battery and separate the connector before opening the drive unit compartment or inspecting or repairing the electrical system. If a tool causes a short circuit, the high current flow from the battery can cause an injury or parts damage.

Sheet 3: Electrical System The capacitor in the transistor controller can hold an electrical charge after the battery is disconnected. To prevent electrical shock and injury, discharge the capacitor before inspecting or repairing components in the drive unit compartment. Wear safety glasses. To discharge the capacitor, first disconnect the battery. Then connect an insulated jumper wire between the B+ and B-terminals (Figure 3-11) of the transistor controller.

Some checks require the battery to be connected. Do not connect the battery until the procedure tells you to connect the battery. Make sure the drive wheel is raised to prevent truck movement and possible injury. Raise the drive wheel as described in the Operating Manual or the PERIODIC MAINTENANCE section of the Service Manual.

CHECKING CONTACTOR COIL Check the Forward or Reverse contactor coil with an ohmmeter. A suppressor diode is connected across the coil terminals. The diode will cause the ohmmeter to indicate a difference in resistance in one direction. Reverse the probes of the ohmmeter to the opposite terminals and measure the resistance. Use the highest resistance indication.

Replace the coil if the resistance readings are a short circuit in both directions or if there is an open circuit in, both directions. Make sure the coil wires are connected again to the correct terminals. Refer to Contactors-General within this section.

CHECKING TRANSISTOR CONTROLLER The controller Is protected against operation with a low battery. Controller output is slowly decreased as battery voltage decreases. The battery can be low if an operator notices slower operation or less power. This operation is not a defect of the transistor controller. Make sure all checks are done with a fully charged battery.

NOTE: The following checks must be done in the order they are listed because some steps depend on conditions set in previous steps.

CHECKS WITH CONTROLLER INSTALLED 1. Raise the drive/steer wheel as described in the Operating Manual or the PERIODIC MAINTENANCE section of the Service Manual.

2. Make sure the battery is fully charged.

3. Make a physical check that battery negative is connected to the B - terminal of the controller. Connect the negative meter lead to the B -terminal, 4. Check for battery positive voltage at the B+ terminal of the controller and the cable T2 terminal of the Reverse contactor. If there is no battery positive voltage, check the cables between battery positive and the two terminals.

If the cables are not defective, the controller can be defective.

5. Make sure the key switch is in the OFF position and remove the wires 29 and 26 from terminals 1 and 2 of the controller. Do not disconnect the resistor between terminals 1 and 2. Check for an open circuit (at least I megaohm) between the wires with the Direction/Speed control in the Neutral position. If an open circuit is not obtained, check to see that the accelermeter pot is centered. Check for approximately 1000 to 2250 ohms with the control in either full speed position. Check for at least one megohm between each wire and the lift truck frame. If any of the resistance readings are wrong, check the wiring to the accelerator potentiometer and check the adjustment of the FWD/REV switch. Connect wire 29 to terminal 1 and wire 26 to terminal 2.

6. Connect the voltmeter positive lead to the controller B + terminal. Connect the voltmeter negative lead to the controller M - terminal. Move the key to the ON position and close the brake switch. Check for zero or near zero volts. Move the Direction/Speed control for full speed travel. Check for full battery voltage.

7. If there is not full battery voltage, the controller is detective. If there is battery voltage and the motor does not operate, disconnect the battery connector and discharge the internal capacitor. The correct procedure to discharge the capacitor is described in the WARNING at the beginning of this section.

8. Disconnect the cable from the controller A2 terminal. Use the ohmmeter to check for a diode between the A2 and B+ terminals. There must be a high resistance in one direction and a low resistance with the meter leads reversed. If there is a low or high resistance in both directions, the diode is defective. If the readings are correct and the motor does not operate, there is a short in the motor circuit, Check for a short at the motor cables or directional contactors. If the cables and contactors are good, the motor has a short.

Sheet 3: Electrical System

Figure 3-11 -Battery Indicator Voltage Selection

SEQUENCE OF OPERATION The sequence of operation chart describes a complete cycle of the transistor traction chart

Sheet 3: Electrical System

Figure 3-12 -Sequence of Operation

ACCELERATOR POTENTIOMETER NOTE: The direction switch must be correctly adjusted before the accelerator potentiometer can be checked.

The accelerator potentiometer must be adjusted after each installation.

WARNING: Disconnect the battery connector to prevent operation of the hydraulic system or electrical shock and possible injury.

The operator platform can move abruptly and cause an injury when any Lift or Lower buttons are accidentally pushed. Fully lower the operator platform. Remove the key from the key switch and install a tag on the instrument panel stating "DO NOT OPERATE".

1. Disconnect the battery so that the battery connector is completely free.

2. Remove the capscrews that fasten the accelerator panel to the cowl. Disconnect electrical plug X-1 .

3. Use an ohmmeter to check the resistance of the accelerator potentiometer. Check the resistance at the electrical plug connector. Check between wire 26 and wire 28 at the connector. Slowly move the direction/speed

Sheet 3: Electrical System control forward travel and check for a resistance reading of 5K (4500 to 5500) ohms as the forward switch just makes contact. Check that the reading decreases smoothly with no flat areas or infinity readings as the direction/speed control is moved to the maximum position. Do the checks again for the reverse direction, The two resistance readings must be equal within 10% when each switch makes contact. When the direction/speed control is moved to the maximum position, the ohmmeter reading must be 200 ohms or less, in either direction.

4. If all of the checks of Step 3 are correct, the accelerator potentiometer is good and correctly adjusted. Connect the electrical connectors. If there were flat areas or infinity readings, the potentiometer must be replaced. If the resistance readings were smooth, but the values were not correct, adjust the potentiometer as described in Step 6 of this procedure.

5. If the potentiometer does not need adjustment or replacement and no other parts will be checked, connect electrical plug X-1 and install the accelerator cover.

6. To adjust the potentiometer, do the following steps: a. Match mark the gear mounted on the potentiometer and the directional/speed control handle. b. Remove the two pan head screws retaining the potentiometer support to the mounting bracket. c.

Connect an ohmmeter as in Step 3. Loosen the setscrew that fastens the pinion gear to the shaft of the potentiometer. Hold the potentiometer in the mount position. The setscrew normally holds the potentiometer in the mount position. Use a screwdriver to turn the shaft of the potentiometer slightly without moving the pinion gear. Temporarily tighten the setscrew. Rotate the pinion gear and check the two readings as in Step 3. The pinion gear must always be in the neutral position after each check. Continue to repeat this step until the two readings are within 10 %. Make certain the match marks are in alignment.

d. Carefully tighten the setscrew to 0.06 to 0.11 Nom (0.56 to 0.94 Ibf in) torque without moving the pinion gear from the neutral position. Make sure that the setscrew is also tightened to hold the potentiometer so that the body cannot rotate. e. Do Step 6c to check that the adjustment is still correct. If necessary, do Step 6c and 6d again until the checks in Step 3 are correct after the setscrew is tightened to the correct torque value. f.

Connect the electrical connectors, install and fasten the instrument panel cover.

ADJUSTMENTS WARNING: Disconnect the battery and separate the connector before opening the drive unit compartment or inspecting or repairing the electrical system. If a tool causes a short circuit, the high current flow from the battery can cause an injury or parts damage.

The capacitor in the transistor controller can hold an electrical charge after the battery is disconnected. To prevent electrical shock and injury, discharge the capacitor before inspecting or repairing components in the drive unit compartment. Wear safety glasses. To discharge the capacitor, first disconnect the battery. Then connect an insulated jumper wire between the B + and B -terminals (Figure 3-11) of the transistor controller.

Some checks require the battery to be connected. Do not connect the battery until the procedure tells you to connect the battery. Make sure the drive wheel is raised to prevent truck movement and possible injury. Raise the drive wheel as described in the Operating Manual or the PERIODIC MAINTENANCE section of the Service Manual.

The controller has three adjustments: Braking (plugging), Current Limit and Controlled Acceleration. The plugging adjustment adjusts the maximum rate that the lift truck will stop. The Direction/Speed control can be moved to the maximum speed position from stop or a slow travel speed. The controlled acceleration adjustment allows adjustment of the maximum rate of acceleration. The current limit control limits the motor current to a preset maximum.

ADJUSTING PLUGGING Turning the braking (plugging) adjustment clockwise will increase the plugging effect and stop the lift truck in a shorter distance. Turning the adjustment counterclockwise will decrease the plugging effect. The traction motor brushes have a faster wear rate when the control is set for the shortest stopping distance (maximum Plugging). More heat is also generated at this maximum setting,

ADJUSTING ACCELERATION Turning the controlled acceleration adjustment clockwise will increase the acceleration rate. Turning the adjustment counterclockwise will give a slower rate of acceleration. The traction motor brushes have a faster wear rate when the

Sheet 3: Electrical System control is set for the maximum acceleration rate. More heat is also generated at this maximum setting.

ADJUSTING CURRENT LIMIT Turning the current limit adjustment counterclockwise will lower the current limit. This setting is factory set at the maximum 400 amps. Lowering this adjustment may cause the truck to have limited starting torque and may not run at top speed when fully loaded.

WARNING: Disconnect the battery and separate the connector before opening the drive unit !M compartment or inspecting or repairing the electrical system. If a tool causes a short circuit, the high current flow from the battery can cause an injury or parts damage.

Figure 3-13 - Controller Adjustment Locations The capacitor in the transistor controller can hold an electrical charge after the battery is disconnected. To prevent electrical shock and injury, discharge the capacitor before inspecting or repairing components in the drive unit compartment. Wear safety glasses. To discharge the capacitor, first disconnect the battery. Then connect an insulated jumper wire between the B+ and B -terminals (Figure 3-11) of the transistor controller.

Some checks require the battery to be connected. Do not connect the battery until the procedure tells you to connect the battery. Make sure the drive wheel is raised to prevent truck movement and possible injury. Raise the drive wheel as described in the Operating Manual or the PERIODIC MAINTENANCE section of the Service Manual.

REPLACING CONTROLLER Make an identification and disconnect the wires and cables from the controller. Remove the mounting screws and remove the controller. Install the replacement controller on the lift truck. Connect the wires and cables to the same terminals as identified during the removal procedure.

CAUTION: When replacing the controller, make certain to replace it with one having the same voltage as the one being replaced.

TROUBLESHOOTING This section describes the most common faults that can occur in trucks with the CURTIS TRANSISTOR CONTROLLER. Follow the General Procedures to make sure that maintenance problems give the correct troubleshooting results. Follow the General Procedures and then use the fault procedure that best describes the problem.

WARNING: Disconnect the battery and separate the connector before opening the drive unit ' compartment or inspecting or repairing the electrical system. If a tool causes a short circuit, the high current flow from the battery can cause an injury or parts damage.

The capacitor in the transistor controller can hold an electrical charge after the battery is disconnected. To prevent electrical shock and injury, discharge the capacitor before inspecting or repairing components in the drive unit compartment. Wear safety glasses. To discharge the capacitor, first disconnect the battery. Then connect an insulated jumper wire between the B + and B -terminals (Figure 3-11 ) of the transistor controller.

Some checks require the battery to be connected. Do not connect the battery until the procedure tells you to connect the battery. Make sure the drive wheel is raised to prevent truck movement and possible injury. Raise the drive wheel as described in the Operating Manual or the PERIODIC MAINTENANCE section of the Service Manual.

Sheet 3: Electrical System 1. Check the specific gravity of the battery. If the specific is less than 1,260, the battery is not fully charged or has a defect. A fully charged battery has a specific gravity of 1 .270-1 .290. A discharged battery has a specific gravity of approximately 1.130.

2. The electric lift truck has a two-wire system. The frame must not be a common electrical path, Check for 50,000 ohms or more between each terminal of the battery connector for the lift truck and a clean connection on the frame. Remove any circuit paths between the controller and the frame of the lift truck. Carbon dust in a motor or other parts can cause a circuit path. Check for additional equipment that is causing a circuit path to the frame.

3. Check for voltage between each terminal of the connector that fastens to the battery and a clean connection on the frame. Normally there is some small voltage between the battery and the frame even if the resistance is very high. The small voltage is normally less than 30% of the battery voltage. A higher voltage can indicate a dirty battery or a battery with a defect. Clean the battery and battery compartment as necessary, 4. Visually check for parts or wires that are loose or damaged.

NOTE: The correct meter polarity is necessary for the checks. The voltage checks are made between the point indicated in the troubleshooting chart and battery negative. Connect the meter negative to battery negative.

NOTE: Make an identification of any wires before you disconnect them. The wires must be connected correctly after checks or repairs.

FAULT NUMBER 1. ONE DIRECTIONAL CONTACTOR WILL NOT CLOSE Possible causes: • Defective (open) wire(s) in control circuit • Direction switch is defective • Contactor coil is defective • Also check disconnect module, power steering contactor coil, Fuse 6, limit switches or defective key.

FAULT NUMBER 2. DIRECTIONAL CONTACTOR WILL NOT CLOSE FOR OPERATION IN EITHER DIRECTION Possible causes: • • • • • • •

Battery not connected Control fuse is defective Pump motor fuse is defective Battery voltage is low Wires in circuit are open Key switch or brake switch is defective Transistor controller is defective

Sheet 3: Electrical System

FAULT NUMBER 3. LIFT TRUCK WILL NOT MOVE IN EITHER DIRECTION.THE DIRECTIONAL CONTACTORS CLOSE NORMALLY. NO POWER WHEN DIRECTION/SPEED CONTROL IS MOVED. Possible causes: • Traction fuse is defective • Open circuit between motor and contactors • Power contacts of direction contactor are defective • Accelerator potentiometer is defective or needs adjustment • Drive motor is defective • Defective (open) traction motor cables • Transistor controller is defective

Sheet 3: Electrical System

FAULT NUMBER 4. DIRECTIONAL CONTACTORS CLOSE, LIFTTRUCK ACCELERATES TO FULL SPEED IMMEDIATELY. Possible causes: • Accelerator potentiometer is defective or needs adjustment • Transistor controller is defective

Sheet 3: Electrical System

CONTACTOR AND ELECTRICAL PANELS-CHECKS AND ADJUSTMENTS NOTE: NEVER make adjustments if the system or components are operating correctly.

WARNING: Do not operate a lift truck that needs adjustment or repairs. Report the need for adjustment or repairs immediately. If adjustment or repair is necessary, put a "DO NOT OPERATE" tag on the instrument panel. Remove the key from the key switch, Some of the checks and adjustments are done with the battery connected. Never have any metal on your fingers, arms or neck. These metal items can accidentally make an electrical connection and cause an injury.

CAUTION: Correct meter polarity is necessary for some checks. Meter correct positive is indicated as (+). Meter correct negative is indicated as (-) Use a meter with a minimum rating of 20,000 ohms per volt to make measurements. Most digital voltmeters are good.

NOTE: To perform the following component tests or to replace any of the components, the drive unit compartment doors must be opened and the drive unit compartment cover must be removed. Refer to Section 2.

CONTROL AND POWER FUSES All the fuses used on the OS30EB are located in the electrical compartment. Remove the cover over the electrical compartment for access. The condition of some fuses can be checked by looking at them. Other fuses do not change in looks and must be checked with an ohmmeter. Disconnect the battery before checking fuses.

The power fuses, traction circuit (FU1) and pump motor (FU2) are on the contactor panel, next to the pump contactor. The steering gear motor fuse FU3 is located on the electrical panel adjacent to the contactor panel.

Control fuse FU4 is located on the contactor panel, immediately above the pump contactor. The fuse for the BDI or the voltmeter, FU5 is also on the contactor above FU4 and the pump contactor. An additional control fuse FU6 is located on the electrical panel adjacent to FU3. Sizes of the fuses are as follows: • • • • • •

FU-1 Power Fuse (Traction Circuit) FU-2 Power Fuse (Pump Motor) FU-3 Steering Gear Motor FU-4 Control Fuse FU-5 BDI or Voltmeter FU-6 Control Fuse

Sheet 3: Electrical System

Figure 3-14 -Fuse Locations

CONTACTORS -GENERAL In an electric truck wiring circuit, contactors are used to perform the task of "Making" or "Breaking" the main power circuits for different functions, such as the drive motors, hydraulic pumps, power steering pumps, etc. Contactors are basically remote control switches for high current applications and serve several purposes. First, they allow the truck to use shorter cables for the high current carrying power circuits, resulting in less resistance and better efficiency.

Second, they allow the use of lighter gauge wire for the control circuits (such as directional switches, accelerator switches, etc.) by separating the control and power circuits. This creates great cost savings in lighter duty components, safer designs (by removing high electrical currents from areas of possible operator contact), reducing heat and power losses, and creating less maintenance problems by reducing current in the controls.

The contactor uses a low amperage current from the control switch to energize a magnetic coil. This coil then creates a magnetic force that draws the contact arms together, closing the circuit for the high amperage current, allowing it to flow through the contactor. When the control switch is opened it stops the flow of current to the magnetic coil, and a return spring opens the contact arms. Because of the arcing that occurs during closing and opening of these high current contact arms, contact tips made of precious metals or alloys are used to prevent welding of the tips. Also, contactors are designed with an "over travel" feature. The connection between the coil armature (which provides the actual motion that closes the tips) and the contact tips is always a spring dampened connection. The coil armature actually travels farther than what is required to close the tips, and this 11 over travel" compresses the armature spring.

This squeezing or wiping action prevents the tips from bouncing as they close. This bouncing would cause arcing of the tips, creating high spots, which could concentrate any further arcing in one spot, welding the tips together.

Because of this arcing, contact tips should be frequently checked for wear.

Two basic types of contactor assemblies are used in industrial truck electrical circuits. For forward or reverse operation, single-pole, double-throw contactors are used. This means there is a pair of normally open tips and a pair of normally closed tips. "Normally Open" means that the tips are open when NO current is applied to the magnetic coil. The 1-A and pump contactors use a single-pole, single-throw arrangement, meaning that there is only one pair of normally open tips.

Figure 3-15 -Schematic Symbols

Sheet 3: Electrical System SPIKE SUPPRESSION Voltage spikes occur each time the contactor coils are de-energized. To control these spikes, various devices are used. On the OS30EB truck the spike suppression used is a diode and resistor in series mounted externally across the contactor coil. These spike suppressors prevent damage to the electrical circuit and extend contact tip life.

MAINTENANCE OF CONTACTOR ASSEMBLIES As mentioned before, contact tips must be checked frequently. Burn marks are a normal condition created by arcing as the tips open. Extremely worn or pitted tips should be replaced, preferably in pairs. Rapid wearing of tips could be caused by one or more of the following conditions: 1. Operating truck on a low-charged battery.

2. Pushing loads, creating high current draw.

3. Allowing contactors to drop out while under heavy load conditions, such as negotiating a steep ramp.

4. Faulty spike suppressors.

5. Improper contact tip adjustment.

When replacing tips, make sure the new tips have the same amp carrying capacity and are direct replacements for the original tips. Also avoid using cheap substitutes. Contactor assemblies are designed to give a wiping action or squeezing action as the normally open tips come into contact. This helps to prevent welding and bouncing of the tips.

On most contactors there is a specified gap setting for the normally open tips and normally closed tips.

TESTING CONTACTORS WARNING: Parts of this procedure require working on the truck with full electric current present. Do not wear any rings jewelry, or a watch while working around the contactor panel. Whenever manually closing a contactor with the power connected, use a properly insulated tool.

1. Jack up the drive wheel of the truck so that clear of the floor. Block the chassis up in this position and remove the jack.

CAUTION: Never operate the drive motor at full speed for more than a few seconds without a load (such as when the drive wheels are up off the floor). A series-wound DC motor will continue to accelerate indefinitely until it exceeds its designed maximum RPM, at which point it will self-destruct.

2. Check the condition of the battery. If it is not fully charged, recharge or replace the battery with a fully charged battery before continuing.

3. Visually check to see if contactor closes when circuit is energized. If contactor closes, skip to Step 9. If contactor does not close, proceed to Step 4.

4. Check for battery voltage at the contactor coil. Connect the positive lead of the meter to the positive side of the coil. To eliminate any false readings caused by other components (such as a driver module connected on the negative side of the coil circuit), connect the negative meter lead to battery negative. Close all switches required to energize the contactor coil and observe the meter reading: a. No Voltage: Open circuit in control circuit wiring to contactor. b. Low Voltage: High resistance in control circuit wiring to contactor. c.

Full Battery Voltage: No problem with control circuit-problem is probably in contactor. Proceed with test.

5. Check at the contactor for loose, broken, or corroded connections at the contactor.

6. Check the mechanical function of the contactor. Use a properly insulated tool, such as an electrician's screwdriver, to manually close the contactor tips. Check for looseness or binding of the moving parts of the contactor. The contactor should move freely, but the parts must not be so loose that the movement is sloppy.

7. Visually check the condition of the tips for pitting, burning, or wear.

8. Check the ohm value of the contactor coil. Disconnect the leads from one side of the coil and connect an ohm meter across the coil. Reverse the ohm meter leads and check in the opposite polarity (since spike suppressors

Sheet 3: Electrical System on some coils make them polarity sensitive). Compare the ohm reading against the ohm value for the type contactor being tested. Ohm values for G.E. contactors readings that vary from these values may be caused by:

9. If the contactor closes but the truck does not work properly, check the electrical function of the high current section of the contactor (the tips and bus bars). With the truck battery connected and all switches closed, connect a voltmeter across the high current terminals of the contactor.

Set the voltage scale of the meter to the lowest range higher than battery voltage (50 volt range for 24 volt battery, etc.). On forward and reverse contactors, a reading of zero volts with the contactor open should be obtained, then the meter should jump as the contactor closes and immediately drop to zero or close to zero. This is the voltage drop across the contactor. On pump contactors, you should read battery voltage across the contactor with the tips open, and it should drop to zero or near zero volts as the lips close.

A high voltage drop (2 volts or more) across the tips indicates poor contact or high resistance. Check for burned or worn tips, incorrect size or mis-matched tips, and for incorrect gap settings on those contactors with adjustable point gaps.

CONTACTORS The "FORWARD" and "REVERSE" contactor assembly controls the direction of current flow through the traction motor. The contactor is a heavy-duty switch that opens and closes the power circuit. The traction circuit has a "FORWARD" and "REVERSE" contactor assembly. Each contactor assembly has the following parts: two sets of normally open (NO) contacts, two sets of normally closed (NO contacts and a coil. The coil is an electromagnet that moves the NO contacts to the closed position against spring pressure. The coil is in the control circuit. The contactor tips are in the traction circuit. A suppressor is connected to each coil.

When a contactor coil is energized, the normally open (NO) contacts close and the normally closed (NC) contacts open. Current flows through the traction motor field in one direction when the "FORWARD" contactor is energized and in the other direction when the "REVERSE" contactor is energized. This action gives direction control to the traction motor. The contacts normally have a long service life because the current flow through the contacts is stopped before the contacts open. The FETs are "OFF" before the contactor coil de-energized.

CONTACTOR-REMOVE AND INSTALL WARNING: Disconnect the battery and separate the connector before opening the drive unit and compartment or inspecting or repairing the electrical system, If a tool causes a short circuit, the high current flow from the battery can cause an injury or parts damage.

The capacitor in the transistor controller can hold an electrical charge after the battery is disconnected. To prevent electrical shock and injury, discharge the capacitor before inspecting or repairing components in the drive unit compartment. Wear safety glasses. To discharge the capacitor, first disconnect the battery. Then connect an insulated jumper wire between the B+ and B -terminals (Figure 3-11) of the transistor controller.

Some checks require the battery to be connected. Do not connect the battery until the procedure tells you to connect the battery. Make sure the drive wheel is raised to prevent truck movement and possible injury. Raise the drive wheel as described in the Operating Manual or in Section 6 of this Manual.

Make sure the battery is disconnected and the capacitor in the controller is discharged. The correct procedure to discharge the capacitor is described in the WARNING, Make an identification of the wires and cables and disconnect them from the contactor assembly. Remove the mounting screws and replace the contactor assembly. Install the mounting screws and reconnect wires and cables as removed.

CONTACTOR DISASSEMBLY AND ASSEMBLY NOTE: If both the contacts and coil of a contactor will be replaced, replace the complete contactor as described in REPLACING THE CONTACTOR. Do only the parts of the procedure necessary to replace the defective parts being replaced.

Sheet 3: Electrical System NOTE: All of the contacts for each contactor must be replaced at the same time if any contact requires replacement.

The contactor contacts are made of special silver alloy. The contacts will look black and rough from normal operation, This condition does not cause problems with the operation of the lift truck. Cleaning is not necessary. DO NOT USE A FILE ON THE CONTACTS. DO NOT LUBRICATE THE CONTACTS. Replace the contacts when the silver alloy is worn away to the base support metal. Replace the contactor parts as follows: 1. Remove the contactor as described in CONTACTOR REMOVE AND INSTALL. 2. Make an identification of the buss bars for correct installation. Remove the buss bars and nuts that fasten the fixed contacts.

3. Remove the two screws that fasten the covers for each contactor. Remove the cover of each contactor. Do NOT lose the plunger springs.

4. Replace the four fixed contacts in the contactor covers.

5. Remove the two plunger assemblies and movable contacts and replace the three fixed contact bars. Replace the contacts of the plungers.

6. If a coil will be replaced, remove the cover base. Remove the screws that fasten the coil frame to the mount bracket. Remove the coil and frame. Remove the bushing part of the plunger and the armature cap from the coil.

Install these parts on the replacement coil.

7. Install the coil and frame on the mount bracket.

8. Install the cover base, fixed contact bars and plungers on the coil frame. Make sure both springs are on both plungers.

9. Install the covers and electrical bars on the covers as removed during disassembly.

10. Install the contactor assemblies on the lift truck as described in REPLACING COMPLETE CONTACTOR,

Sheet 3: Electrical System

Figure 3-16 -Forward and Reverse Contactors 1.

2.

3.

4.

5.

6.

7.

8.

9.

Screw-Top Cover Hardware Kit Top Cover Return Spring Moving Contact Fixed Contact Insulator Coil and Frame w/Bracket End Cap

Sheet 3: Electrical System

Figure 3-17 -Pump Contactors 1.

2.

3.

4.

5.

6.

7.

8.

Fixed Contact Moving Contact Top Cover Screw-Top Cover Return Spring Coil and Frame End Cap Auxiliary Contact Kit

Sheet 3: Electrical System

Figure 3-18 -Main Contactor 1.

2.

3.

4.

5.

6.

7.

Fixed Contact Moving Contact Top Cover Screw-Top Cover Return Spring Coil and Frame End Cap

RELAYS-GENERAL The 24", 60",150", 212", and 10° , relays forma logic network to enable traction and limit speeds under varying height and steering conditions. the 1.2 mph speed limit is achieved by switching a 2.7K ohm resistor in series with the throttle pot circuit. The 2.2 mph speed limit is achieved by switching a 6.8K ohm resistor in parallel with the 2.7K ohm resistor, effectively switching 1.9K ohm in series with the throttle pot.

Traction is enabled by a logic network of the 10°,150", and 212" relays, with the logic network connecting the EPS

Sheet 3: Electrical System brake output to the traction enable pin of the Curtis/PMC traction controller.

10°Relay -The 10°relay is part of the logic networks mentioned above. The 10°relay coil is energized by the EPS controller when the steer tire is within 10°maximum of straight travel 24" Relay -The 24" relay is part of the logic networks mentioned above. The 24" relay coil is energized by the 24 inch proximity switch when the fork elevation is 24" or below.

60" Relay -The 60" relay is part of the logic networks mentioned above. The 60" relay coil is energized by the 60 inch proximity switch when the fork elevation is 60" or below.

150" Relay -The 150" relay is part of the logic networks mentioned above. The 150" relay coil is energized by the 150 inch proximity switch when the fork elevation is 150" or below. On trucks with maximum fork height below 150", the relay coil is energized by a jumper which replaces the 150" proximity switch.

212" Relay - The 212" relay is part of the logic networks mentioned above. The 212" relay coil is energized by the 212 inch proximity switch when the fork elevation is 212" or below. On trucks with maximum fork height below 212", the relay coil is energized by a jumper which replaces the 212" proximity switch.

RELAYS-REMOVAL AND INSTALLATION 1. Open the drive unit compartment doors. Disconnect the battery. Remove the drive unit compartment cover.

2. Tag and remove the wires from the relay.

3. Remove mounting screws.

4. Mount the relay on the electrical panel. Install the mounting screws.

5. Install the wires on the relay.

6. Install the drive unit compartment cover, close the drive unit compartment doors and reconnect the battery.

7. Test the truck for proper operation.

TESTING DIODE BLOCK If the diode block is suspected of not functioning properly, the diode block should be tested for continuity.

Use an ohm meter and test for low resistance between wires 75 and 76.

Reverse the leads. The reading on the ohm meter should read infinity.

REPLACING DIODE BLOCK 1. Open the drive unit compartment doors. Disconnect the battery. Remove the drive unit compartment cover 2. Identify and remove the wires from the diode block.

3. Remove the mounting screws.

4. Mount the replacement diode block on the electrical panel. Install the mounting screws.

5. Install the wires on the diode block.

6. Install the drive unit compartment cover, close the drive unit compartment doors and reconnect the battery.

7. Test the truck for proper operation.

TESTING POWER STEERING SOLENOID If the solenoid is suspected of not functioning properly the solenoid should be tested for shorts.

Identify and disconnect all the wires. Use an ohm meter to test for resistance across the secondary terminals. A reading of 50 ohms ±10% should be obtained. If the ohm meter reads either zero ohms or infinity the solenoid must be replaced.

Sheet 3: Electrical System REPLACING POWER STEERING SOLENOID 1. Open the drive unit compartment doors. Disconnect the battery. Remove the drive unit compartment cover 2. Identify and remove the wires from the solenoid.

Figure 3-19 -Power Steering Solenoid 3. Remove the capscrews retaining the solenoid on the electrical panel.

4. Assemble the replacement on the electrical panel.

5. Install the wires on the solenoid.

6. Install the drive unit compartment cover, close the drive unit compartment doors and reconnect the battery.

7. Test the truck for proper operation.

Figure 3-20 -Instrument Panel Arrangement

Sheet 3: Electrical System ACCELERATOR POTENTIOMETER-REMOVAL AND INSTALLATION WARNING: The operator platform can move abruptly and cause an injury when any Lift or Lower buttons are accidentally pushed. Fully lower the operator platform. remove the key from the key switch and install a tag on the instrument panel stating "DO NOT OPERATE".

Disconnect the battery connector to prevent operation of the hydraulic system or electrical shock and possible injury.

1. Disconnect the battery.

2. Remove the four capscrews that fasten the instrument panel cover to the cowl.

3. Match mark the gear mounted on the potentiometer and the direction/speed control handle.

4. Disconnect electrical plug X-1.

5. Remove the two pan head screws retaining the potentiometer support to the mounting bracket.

6. Remove the setscrew retaining the gear on the potentiometer shaft and remove the potentiometer. The gear will come off as the potentiometer is removed.

7. Install a new potentiometer into the opening of the potentiometer support. Align the potentiometer with the locating pin on the support. The gear must be held between the supports so that the gear is placed on the potentiometer shaft as the potentiometer is installed.

8. Move the gear so that the match marks are aligned. Install the setscrew to retain the gear on the potentiometer.

9. Install the potentiometer support. Adjust the accelerator potentiometer. Refer to ACCELERATOR POTENTIOMETER ADJUSTMENT. 10. Connect electrical plug X-1.

11. Install the instrument panel cover.

12. Connect the battery and test the operation of the truck.

FORWARD AND REVERSE SWITCHES-REMOVAL AND INSTALLATION 1. Disconnect the battery.

2. Remove the four capscrews retaining the instrument panel to the cowl.

3. Disconnect electrical plug X-1.

4. Remove the two pan head screws retaining the potentiometer support.

5. Disassemble the switch, either forward or reverse, from the potentiometer support. Identify and disconnect the electrical wires.

6. Install the wires to the proper terminals.

7. Install the potentiometer support. Check the accelerator potentiometer adjustment. Refer to ACCELERATOR POTENTIOMETER ADJUSTMENT. NOTE: The only adjustment for the forward or reverse switches is the neutral position of the pinion gear. The position of the pinion gear is set during replacement or adjustment of the accelerator potentiometer.

8. Connect the electrical plug X-1 .

9. Install the instrument panel cover.

10. Connect the battery and test the operation of the truck.

TROUBLESHOOTING -ACCELERATOR SWITCH

Sheet 3: Electrical System

LIFT AND LOWER SWITCHES-REMOVAL AND INSTALLATION 1. Disconnect the battery.

2. Disconnect electrical plug.

3. Remove the two pan head screws retaining the shaft support to the mounting bracket.

4. Disassemble the switch, either lift or lower from the shaft support, Identify and disconnect the electrical wires.

5. Install the wires to the proper terminals. Install the switch in the shaft support, 6. Install the shaft support on the mounting bracket. Check to make certain that the gears are properly aligned.

7. Connect the electrical plug.

8. Install the instrument panel cover.

9. Connect the battery and test the operation of the truck.

Sheet 3: Electrical System

Figure 3-21 -Gear Tooth Contact Pattern 1.

2.

3.

4.

5.

6.

7.

8.

CONTROL HANDLE HANDLE WELDMENT ROLL PIN WASHER NYLON BEARING BRACKET WASHER HEX HEAD BOLT

Sheet 3: Electrical System 9. SHAFT 10. SCREW 11. POTENTIOMETER 12. BRACKET 13. SCREW 14. GEAR-SPUR 15. GEAR-SPUR 16. PIN-SPRING 17. WASHER 18. SPRING RETURN 19. CAM 20. PIN SPRING 21. BUSHING 22. STANDOFF 23. NUT PLATE 24. INSULATOR 25. SWITCH 26. PLATE SPACER

HORN SWITCH-REMOVAL AND INSTALLATION 1. Disconnect the battery.

2. Remove the four capscrews that fasten the instrument panel cover to the cowl.

3. Disconnect the electrical plug X-1 .

4. Remove the four capscrews that fastens the horn switch cover.

5. Disassemble the switch from the mounting bracket. Identify and remove the electrical wires.

6. Install the switch on the mounting bracket and install the wires to the proper terminal.

7. Install horn switch cover.

8. Reconnect electrical plug X-1 9. Install instrument panel cover on the cowl.

10. Reconnect battery. Turn on key and test the horn switch for proper operation.

INSTRUMENT PANEL-REMOVAL AND INSTALLATION

Figure 3-22 -Instrument Panel Schematic 1. Disconnect the battery.

2. Remove the four capscrews that fasten the instrument panel cover to the cowl.

3. Remove the four screws that fasten the instrument panel to the cowl.

Sheet 3: Electrical System 4. Align the instrument panel on the cowl and install the capscrews.

5. Install the instrument panel cover.

6. Connect the battery.

KEY SWITCH-REMOVAL AND INSTALLATION 1. Remove the instrument panel. See INSTRUMENT PANEL-REMOVAL AND INSTALLATION. 2. Identify and disconnect the electrical wires to the switch.

3. Remove nut retaining the key switch to the instrument panel.

4. Remove the key switch.

5. Install key switch. Make certain the switch is properly aligned before tightening the retaining nut.

6. Connect the wires to the proper terminals.

7. Install the instrument panel. See INSTRUMENT PANEL REMOVAL AND INSTALLATION.

POWER DISCONNECT SWITCH-REMOVAL AND INSTALLATION 1. Remove the instrument panel. See INSTRUMENT PANEL-REMOVAL AND INSTALLATION. 2. Identify and disconnect the electrical wires to the power disconnect switch.

3. Remove the switch from the instrument panel.

4. Install the switch.

5. Connect the wires to the proper terminals.

6. Install the instrument panel. See INSTRUMENT PANEL REMOVAL AND INSTALLATION.

STEERING INDICATOR GAUGE-TESTING The steering indicator gauge can be tested using the schematic and chart below.

Figure 3-23 -Test Steering Indicator Gauge

STEERING INDICATOR GAUGE REMOVAL AND INSTALLATION 1. Remove the instrument panel. See INSTRUMENT PANEL-REMOVAL AND INSTALLATION. 2. Identity and disconnect the wires.

3. Remove the nuts and lockwashers retaining the indicator gauge to the instrument panel.

4. Install the gauge on the instrument panel. Make certain the gauge is properly aligned.

5. Install the wires on the proper terminals.

6. Install the instrument panel. See INSTRUMENT PANEL REMOVAL AND INSTALLATION.

VOLTMETER (STANDARD)-REMOVAL AND INSTALLATION

Sheet 3: Electrical System 1. Remove the instrument panel. See INSTRUMENT PANEL-REMOVAL AND INSTALLATION. 2. Identify and remove the wires.

3. Remove the nuts and washers retaining the gauge to the instrument panel.

4. Install the gauge on the instrument panel. Make certain the gauge is properly aligned.

5. Install the wires on the proper terminals.

6. Install the instrument panel. See INSTRUMENT PANEL-REMOVAL AND INSTALLATION.

BATTERY DISCHARGE INDICATOR (OPTIONAL)-REMOVAL AND INSTALLATION 1. Remove the instrument panel. See INSTRUMENT PANEL-REMOVAL AND INSTALLATION. 2. Disconnect the fifteen-pin plug.

3. Disassemble the hex, nuts and washers holding the retaining bracket. Remove bracket and gauge from the instrument panel.

4. Make certain that the reset and discharge adjustments have been made. Install the gauge in the instrument panel.

5. Connect the fifteen-pin plug.

6. Install the instrument panel, See INSTRUMENT PANEL-REMOVAL AND INSTALLATION.

BATTERY DISCHARGE INDICATOR-RESET AND DISCHARGE ADJUSTMENTS 1. With a screwdriver rotate both Reset and Discharge adjusting screws counterclockwise until completely stopped.

2. Rotate Reset screw clockwise until slot in screw is aligned with area "B".

3. Rotate Discharge screw clockwise until slot in screw is aligned with area "L".

Figure 3-24 -Reset and Discharge Settings

SLACK CHAIN INDICATOR LIGHT-REMOVAL AND INSTALLATION 1. Remove the instrument panel. See INSTRUMENT PANEL-REMOVAL AND INSTALLATION. 2. Identify and disconnect the wires.

3. Remove the light assembly from the instrument panel.

4. Install light into instrument panel.

5. Connect the wires to the proper terminals.

6. Install instrument panel. See INSTRUMENT PANEL REMOVAL AND INSTALLATION.

FOOT SWITCH-REMOVAL AND INSTALLATION 1. Remove the cover of the foot switch assembly.

2. Install labels on the wires of the switch so that the wires can be correctly connected during installation. Remove the wires from the switch terminals.

Sheet 3: Electrical System 3. Remove the screws that fasten the switch in the housing and remove the switch.

4. Install the wires as labeled during removal. Install the wires on the same terminals of the replacement switch and install the switch in the housing. Install the cover.

Figure 3-25 -Foot Switch

LOOSE CHAIN SWITCH-REMOVAL AND INSTALLATION The loose chain switches are at the chain anchors on the mast side of the operator platform.

WARNING: To replace the loose chain switches, the operator platform must be raised to provide access. The lowering of the operator can cause an injury. The operator platform must have a support or a chain to prevent the operator platform from lowering.

1. Raise the operator platform for access to the loose chain switches. Block the operator platform or use chains to prevent the operator platform from lowering. The chains must be fastened to the operator platform and to a part of the mast that can not move.

2. Disconnect the battery.

3. Install labels on the wires for correct connection during installation. Remove the wires from the switch terminals.

4. Remove the nuts that fasten the switches to the bracket and remove the switches.

5. Install the replacement switch on the bracket. Attach the switch to the switch bracket. Adjust the switch to provide proper contact of the cam to the chain anchor. Repeat the operation for the second switch.

6. Connect the wires to the switch terminals as marked during removal.

Figure 3-26 -Loose Chain Switch

Sheet 3: Electrical System LIMIT SWITCH-REMOVAL AND INSTALLATION WARNING: The operator platform can move abruptly and cause an injury when any Lift or Lower buttons are accidentally pushed. Fully lower the operator platform, Remove the key from the key switch and install a tag on the instrument panel stating "DO NOT OPERATE".

1. Raise and block the mast and operator platform high enough to gain access to the 24 inch limit switch located on a bracket welded to the bottom of the mast, The 150 inch limit switch is located on a bracket welded to the right side of the mast (as viewed from the operator platform) approximately 4 ft. from the floor, It is not necessary to raise the mast to remove this switch.

2. Remove the top cover and open the compartment doors.

3. Disconnect the battery. Disconnect limit switch connector.

4. Loosen and remove hex nut retaining switch on the front of the bracket. Remove the switch from bracket.

5. Reverse above procedure to assemble and install.

6. When installing the limit switch, the distance between the target and the sensor should be 0.10 inches.

Figure 3-27 - 24" Limit Switch

Sheet 3: Electrical System

Figure 3-28 - 150" Limit Switch

DRIVE AND HYDRAULIC PUMP MOTORS Routine Maintenance 1. Periodically blow out all motors with clean, dry compressed air.

2. Check for oil or dirt in motor.

3. Check bearings for retention of lubricant.

4. Check to make sure pole pieces are tight.

5. Inspect brushes. Brushes must be replaced when they are worn to one halt their original length. When replacing brushes, make certain ALL brushes are changed and properly seated. Brushes must be able to move freely.

Make sure they are not too tight in the brush holders.

6. Visually inspect the commutator. Commutator should be smooth, with a rich chocolate brown color.

7. Never run the motor at full speed for more than a few seconds without a load (such as with the drive wheels raised off the floor). A series wound DC motor will continue to accelerate until it exceeds its designed maximum RPM, and self-destruct.

WARNING: Make sure motor covers, if used, are replaced before operating truck.

8. When ordering motor parts, be sure to state both model and serial numbers of truck, model number of motor and voltage.

Preventive Maintenance Preventive maintenance on electric motors is recommended to be performed at 200-hour intervals under normal operating conditions.

Under heavy duty, dusty and dirty conditions, preventive maintenance on electric motors must be performed more frequently, depending on the conditions and the environment in which the electric truck is running.

Proper electric motor preventive maintenance will aid in detecting many problems before they become serious.

Maximum performance from electric motors and reduced maintenance costs can be obtained by performing the following periodic preventive maintenance checks-which can be performed on motors while in the truck.

1. Disconnect battery while checking electrical connection.

Sheet 3: Electrical System 2. Open cover for access to drive motor.

3. Open cover for access to hydraulic pump motor.

Cleanliness Electric motors must be kept clean and dry internally and externally; free of dust, dirt, grease, oil, chemicals, moisture, water, carbon dust, and metallic chips. Blow off contamination with compressed air. If internal oil or grease contamination is present, the motor should be disassembled and the individual parts washed in a suitable cleaning solvent.

Connections Check every screw, bolt, and nut for tightness. Especially check the pigtails of the brushes, the brush holders, power lead connections, and field jumper connections.

Discoloration and Burn Marks Discoloration and burn marks usually indicate that the motor or certain components of the motor have been overheated due to stalled conditions, loose connections, insulation break-down, or contamination. If signs of overheating are present, determine the cause and perform necessary repairs. The commutator should be smooth, free of burn marks, and have a chocolate brown color. Inspect the brushes, the brush holders, the brush springs, and the insulation for discoloration.

Brushes Brushes should be inspected to make certain they are not worn to less than one half original length. The brushes must be free to move in the brush holders and should not have too much clearance. Check the brush springs for proper tension. If the brushes have to be replaced, use only specified brushes for a specific motor.

Commutator Check that carbon dust and other foreign matter is not caked on the undercut mica between the copper bars.

The mica separators should be below the segment face. There should not be any thrown solder from the armature risers. Check that the brazed connections are not loose.

If grease, oil, or corrosive materials are present, wipe clean with a cloth and wash with soap and water. Clean up the surface of the commutator with a commercially available commutator stone if necessary. Take the necessary steps to prevent reappearance.

Bearings Check bearings for noise and rough spots while the armature is rotating. Inspect the bearings for damaged seals.

Only original equipment sealed bearings with high temperature lubricants should be used if replacement is required.

Do not be misled by identifying numbers on the bearings. The high temperature lubricant is not specified in the identification number.

CAUSES OF MOTOR FAILURE Overload Motors have a specific rating of voltage and current at which they are designed to operate. Should a motor be subjected to a severe overload for substantial periods of time, overheating will result. Pushing loads, working on ramps of too steep a grade, and attempting to lift loads greater than the capacity of the truck are just a few overload conditions. The end result of this overheating is the throwing out of solder in the commutator riser, and bearing failure due to excessive heat. Also thrown or lifted commutator bars may occur, or insulation breakdown may occur.

Shock Loading Shock loading can result from severe (stiff) plugging of the drive motor. This will cause excessive current draw, as the motor at the time of plugging is at stall point. Breaking of the armature shaft could result from plugging.

Sheet 3: Electrical System Short in Field Coils A short in the field coil or coils causes excessive current draw, again resulting in too much heat. When the truck runs faster than normal, but with little or no torque, it is an indication of a short in the field coils.

Short in Armature A shorted armature or coils will increase the current draw. A visual inspection of the commutator will show burn marks on the commutator bars connected to the shorted coil or coils.

Short Brushes Short brushes cause arcing on the commutator and excessive heat. In addition to brush replacement, turning and undercutting of the commutator may be all that is required, provided the damage is not too great. Check for damage from shunts hitting the commutator.

High or Low Commutator Bar When one of the bars is protruding above or lying below the normal diameter of the commutator, the result is excessive brush wear and arcing of the brushes. Usually a clicking sound will be heard when armature is rotating.

Open Circuit An open circuit in the field or armature coils of the motor.

Low Battery Voltage Low voltage causes excessive current draw and increased heating. Also, accelerated brush wear may occur.

Eccentricity of Commutator Eccentricity of commutator causes rapid brush wear, excessive sparking of brushes, and increased heating.

Over-Speeding Over-speeding of the motor by operating with no load (drive wheels off floor) for more than 30 seconds, or pushing or towing of the truck at more than 5 mph will result in failure of the armature,

MOTOR TESTS When testing electric motors for grounds and shorts in the truck, disconnect armature and field leads from the motor. Use an ohmmeter, RX 10 or RX 100 scale, to check for grounds or shorts in the motor.

The ohmmeter should indicate: 1. A closed circuit between the armature terminals.

2. A closed circuit between the field terminals.

3. Infinity between the motor housing and the armature terminals, with meter on high resistance scale.

4. Infinity between the armature and the field terminals (series wound motors only).

If ohmmeter readings are obtained that indicate a problem, further checks should be made by a qualified electric motor repairman to find the problem and make the necessary repairs.

Excessive Current Draw Excessive current draw is usually caused by shorts in the system allowing current to follow paths that weren't intended. Sometimes excessive current draw can be caused by mechanical malfunctions such as worn bearings, misaligned parts, improper lubrication, and light brake adjustments. Other factors include operator misuse such as operating on steep grades, overloading the truck and pushing loads. The condition of the battery can contribute greatly to excessive current draw. When the battery charge and voltage are low, more current is needed to perform the same task. Since the power required to move a load is Power = Volts x Amperage, as the battery voltage goes down, the amperage must increase to maintain power.

Sheet 3: Electrical System Measuring Current Draw When troubleshooting the electrical system of a battery powered industrial truck, you will need to know the specified current draw of the motor being tested as well as the actual current draw during the test. It a motor draws too much current, excessive heat is created, resulting in damage to the commutator, brushes, armature, and related components.

A motor drawing excessive current can usually be identified by two dark burn marks on the commutator 90°or 180°apart. If a motor draws too much current due to excessive ramp operation, pushing loads, or being stalled, heat damage will occur.

Current draw is measured with a shunt type amp meter in series with the motor. The meter should be capable of reading 600 amps. A 600 amp shunt meter suitable for this purpose is available through your Yale Dealer under part number 5180968-26. Since current draw is measured with the shunt meter wired in series with motor circuit, you must "break" the circuit to insert the meter, This will require disconnecting the main power cable to the motor and connecting the meter in line at this point. In most cases this will require the use of a jumper cable between the meter and the truck terminal post. This jumper should be made up from the same type and gauge cable as the power cable it is replacing, and should be kept as short as practical.

Meter Connections for Current Draw Tests Meter connections for current draw tests must be made in the primary power circuit for the motor being tested. This can be done in several ways. First, some battery cable adapters are available so that you can unplug the battery connection, insert the adapter, and plug the battery connections into either side of the adapter. The meter is then connected to the adapter. A second variation of this is disconnecting the main power lead from the battery connector at the main fuse and connecting the meter in series at this point. Both of these methods allow you to check the current draw of virtually any motor in the truck from one point. You must, however, be careful that you don't read the current for more than one motor. For instance, if measuring drive motor current, you must isolate the power steering motor (if equipped) by either disconnecting the power steering relay, or by inserting an insulator between the power steering relay contactors. If you do not do this, you will be reading both the power steering and drive motor currents at the same time.

WARNING: If operating a truck with the power steering motor disconnected, be aware that steering effort may be greatly increased and steering response may be decreased accordingly. Operate the truck only in a test area requiring little or no maneuvering.

A third method would be to connect the meter directly to the motor power cable. Be sure to pick up the power circuit at a point where both the armature and field coils are included.

Excessive Resistance Excessive resistance is usually caused by loose or corroded terminal connections, poor solder joints and dirty or corroded contacts. Incorrectly sized wiring and poor crimp connections of terminals can also cause excessive resistance.

When too much resistance exists in a circuit, overheating and sluggish or erratic operation will occur .

The best way to rest for excessive resistance is to measure the voltage drop across the suspected component or wire. A wire, fuse, switch or contact tip should have very little or no voltage drop. Therefore, by checking voltage drop, it can be determined if resistance is too high by a high voltage drop. A voltage drop of 0.10 to 0,30 volts is acceptable. A higher reading indicates excessive resistance.

Brush Springs The brush springs should be inspected visually. If the springs are found to be broken or discolored, they must be replaced. Be certain to replace the springs with the recommended spring listed in the parts manual.

DRIVE MOTOR INSPECTION 1. Check commutator for grounds, shorts, or uneven wear.

2. Check bearings; replace if worn or damaged.

3. Check field coils.

4. Check brush holder/assembly.

Sheet 3: Electrical System 5. Replace lock nuts on each end of armature shaft.

Preparation of Drive Motor Commutator In order to ensure the best possible operation from newly-fitted brushes, the commutator should be in good condition.

Check the commutator for: a. Dirt or other foreign matter. b. Eccentricity: 0.002 inches max. runout from shaft -Motors up to 7.312 inches Diameter.

0.003 inches max. runout from shaft -Motors larger than 7.312 inches Diameter c.

High or low bars, roughness or burning.

d. High mica. e. Grooving of commutator.

If any of the above conditions exist, they should be remedied as follows: 2. Clean the commutator by holding a piece of dry canvas or other hard non-tinting material, which is wound around and securely fastened to a piece of wood, against the commutator.

3. If the eccentricity or roughness is not too great, it may be possible to polish the commutator with one of the several varieties of dressing stones available on the market. Before stoning, clean grease and oil from the commutator using a cloth saturated with a suitable solution. After stoning, the commutator should be smoothed with a very fine grade of sandpaper, and then polished by using the back of the paper. When the commutator is too rough or eccentric to be stoned down, it is advisable to turn the commutator on a lathe.

4. Undercut the mica using one of the several types of undercutting tools available on the market. Undercutting is usually done to a depth of 0.047 inches. It is recommended to slightly bevel the segment corners.

5. A commutator that is badly grooved should be ground or turned the same as for roughness or eccentricity. After the commutator has been conditioned, make sure that it is completely cleaned out by suction (preferred), or by blowing out with clean, dry compressed air.

Figure 3-29 -Undercutting Commutator

Fitting Motor Brushes (Motor Removed) 1. Care taken to ensure the best possible commutator and brush running conditions, mechanical and otherwise, will pay dividends along improved commutation.

2. Brushes of different qualities should never be run together on the same commutator. Using brushes of improper compound, or brushes other than those originally specified and manufactured for a specific motor, will cause

Sheet 3: Electrical System commutator damage.

3. Before installing brushes, inspect the brush holders inside and out for burned spots. Make sure that the brush pigtails are properly secured in the brushes, and that the brushes move freely in the brush holders.

4. Fit the new brushes to the commutator surface by using a strip of fine sandpaper placed between the face of the brush and the commutator (sand surface against brush). Use several one direction strokes of the sandpaper, pulled in the direction of the commutator rotates with the forward direction of the truck (drive motor), and in the direction in which the commutator rotates while hoisting (hoist pump motor). Only the pressure of the brush should be on the sandpaper when it is fitted in this matter. Make sure that the complete surface of the brush rides on the cleaned-up surface of the commutator.

5. Following the installation of new brushes, the motor should be blown out with clean, dry compressed air.

DRIVE MOTOR BRUSH-REMOVAL AND INSTALLATION (MOTOR INSTALLED) 1. Disconnect battery, and open drive unit compartment door.

2. Remove screws securing motor cover plates, if equipped.

3. Note position of brush and wire assemblies before removing. When installing brush set, be certain to place brush set and wires in same position as removed.

4. Loosen screw and washer securing brush wire to terminal. Remove brush springs and brush set.

5. Reverse above to install. Refer to Fitting Brushes paragraph in this section.

DRIVE MOTOR BRUSH HOLDER-REMOVAL AND INSTALLATION (MOTOR INSTALLED) 1. Disconnect battery, and open drive unit compartment door.

2. Remove Brush assemblies (Refer to brush removal section).

3. Scribe motor field ring housing and commutator end head to make certain end head is installed in same position as removed.

4. Tag and disconnect drive motor wires from terminals on end head.

5. Remove hex head screws securing end head to field ring.

6. Remove end head assembly.

NOTE: It may be necessary to use a puller to start the end head off the bearing when removing. Do not force, or damage to the end head may result.

7. Remove screws securing brush holder assembly to end head. Inspect all parts for wear or damage, and replace when necessary.

8. Reverse above to install. Be sure the new brush holders are rigid, not sloppy, and there are no loose rivets.

NOTE: Do not drive on end head when installing. Lightly tap using a plastic hammer.

DRIVE MOTOR-REMOVAL AND INSTALLATION 1. Disconnect the battery.

2. Open drive unit compartment.

3. Tag and disconnect power cables to the motor and the wires to the electric brake.

4. Remove bolts mounting the motor to the drive unit.

5. Remove the drive motor with the brake assembly in place using a sling and proper lifting equipment. Refer to Section 5 of this manual for brake disassembly.

CAUTION: Be sure to cover the drive unit opening so that debris does not enter it.

Sheet 3: Electrical System 6. Reverse the procedure to install the drive motor.

DRIVE MOTOR-DISASSEMBLY AND ASSEMBLY 1. Clean and punch mark (or scribe) brake assembly, drive and commutator end heads, and motor field ring housing to simplify assembly of the motor.

2. Remove brushes and brush spring assemblies.

3. Remove elastic stop nut and gear and shims, if necessary, using a socket and impact wrench.

NOTE: When same motor pinion or gear is used, replace shim or shims in same position as removed.

When a new gear set is used, refer to Drive Unit Section 4 for gear setting.

4. Remove screws securing commutator end head. Remove end head. It may be necessary to use a puller to remove. Do not force, or damage to the end head may result.

5. Remove screws securing drive end head. Tap end head loose using a plastic hammer and remove, complete with armature.

IMPORTANT: Be extremely careful not to damage the field coils, pole pieces or armature when removing.

6. Remove the oil seal and the outer snap ring retaining the armature shaft. Remove the inner snap ring retaining the end head.

7. Separate drive end head from armature. The bearing end head will come off with the bearing. It may be necessary to use a puller to remove. Do not force, or damage to the end head may result.

8. Remove screws securing brush holder assembly to commutator end head. Remove brush holder assembly.

9. Remove bearings from end heads if necessary. Refer to Inspection.

10. Replace field coils when necessary, refer to Inspection.

11. Install a snap ring into the slot provided in the armature shaft.

12. Carefully apply Loctite 609 (Yale 501702906) to the area above the snap ring when the commutator bearing will be installed. The Loctite 609 will fill the gap between the bearing and the shaft.

13. Install the bearing on the shaft. There should not be any force against the snap ring when the bearing is installed. The snap ring is used to locate the bearing.

CAUTION: Make certain that none of the Loctite 609 is allowed to get onto the armature or in the bearing.

Wipe off any excess after the bearing is installed.

Figure 3-30 -Commutator End of Armature Shaft NOTE: LOCTITE 609 TAKES APPROXIMATELY 10 MINUTES TO SET UP AND 24 HOURS TO FULLY CURE.

Sheet 3: Electrical System 14. Continue to assemble the motor in the reverse steps of the disassembly. Install a new elastic stop nut to secure the motor pinion gear.

Figure 3-31 -Drive Motor 1. RETAINING RING -INTERNAL 2. BEARING -COMM. END 3. HEX. HD. SCREW 4. HARD WASHER 5. . COMMUTATOR END HEAD 6. TERMINAL KIT 7. TERMINAL SCREW KIT 8. BRUSH HOLDER ASSEMBLY -ONLY 9. FLAT WASHER 10. LOCKWASHER 11. HEX. HD. SCREW 12. BRUSH SET 13. BRUSH SPRING SET 14. ARMATURE ASSEMBLY 15. ARMATURE SHAFT 16. POLE PIECE 17. FIELD COIL SET 18. FIELD RING 19. LOCKWASHER 20. BUTTON HD. SCREW 21. DRIVE END HEAD 22. LOCKWASHER 23. HEX HD. SCREW

Sheet 3: Electrical System 24. BEARING - DRIVE END 25. RETAINING RING EXTERNAL 26. OIL SEAL

HYDRAULIC PUMP AND POWER STEERING MOTORS -MAINTENANCE INSTRUCTIONS Vendor supplied pump motors are generally used where smaller pump requirements are found. Typical vendor supplied motors include those from General Electric, Ohio Motor, etc. Service requirements are similar for all DC motors, but several differences should be observed.

1. Some vendor supplied motors require removal of the commutator end head to replace the brushes (see following procedure).

2. Many vendor supplied motors have an integral cooling fan on the armature shaft. This means that the armature can only be removed through the drive end of the motor, since the fan would interfere with the field coils if you try to remove it through the commutator end.

3. Some smaller motors, particularly power steering motors, are of the permanent magnet type. This means that the field coils are replaced with permanent magnets. These require two special considerations when being serviced: a. Only service these motors in clean areas, since the magnets will attract any ferrous metal particles once the armature is removed. Foreign objects will destroy the motor if not removed. b. Since the permanent magnets exert a relatively strong pull on the armature shaft, keep your fingers clear of possible pinch points when removing or installing the armature.

4. Do not attempt to press the armature shaft out of the armature on vendor supplied motors without first checking your service parts manual. Some motors do not have a separate serviceable armature shaft, and attempting to press the shaft out will destroy the armature.

5. Never run a pump motor for more than a few seconds without the pump attached and connected. Series wound DC motors, without a load, will continue to accelerate indefinitely until they exceed their designed maximum RPM, at which point they will self-destruct.

GENERAL INFORMATION 1. Lubrication -Pre-lubricated ball bearings are supplied. Replace only with original equipment. Press only on the inner race when installing bearings on shaft.

2. Motor brushes need periodic inspection and replacement as wear indicates. Brush wear is greatly influenced by individual application, so it is recommended that the brush wear be checked often to determine future required inspection. When the brushes are worn to half their original length, they should be replaced.

3. If mechanical or electrical failure occurs, first check for proper electrical connections, fusing, or unusual binding of mechanical load. Starting and accelerating torques of D.C. motors are considerably higher than the full load torque of the motor. Care should be taken to prevent damage to driven machinery as a result of the higher starting and accelerating torques. Perform motor tests as outlined in this section.

BRUSH REPLACEMENT -HOIST PUMP MOTORS 1. Disconnect battery. Open the drive unit compartment doors. Remove the drive unit compartment top cover.

2. Remove the cover from the commutator end head.

3. Remove the brush springs and remove the brushes.

4. Inspect brushes for excessive wear.

5. Reverse steps above to assemble.

HOIST MOTOR -REMOVAL AND INSTALLATION 1. Disconnect the battery.

Sheet 3: Electrical System 2. Remove the pump mounting bolts.

3. Move the hoist pump away from the motor.

4. Identify and remove the power cables.

5. Remove the four hex, head screws securing the hoist motor to the truck frame.

6. Reverse the steps above to install the motor.

HOIST MOTOR-DISASSEMBLY AND ASSEMBLY 1. Punch mark end heads and frame to ensure correct placement of end heads when reassembling the motor.

2. Loosen screw securing cover band and slide off band.

3. Remove brush springs and brushes.

4. Remove two screws and nuts securing the stator and commutator end head together. Remove the cap screws and nuts retaining the drive end head and the commutator end head to the stator. Carefully remove the commutator end head. Remove brush ring and brushes.

5. Remove drive end head. Remove the armature from the stator.

IMPORTANT: Be extremely careful not to damage the field coils, pole pieces or armature when removing.

Figure 3-32 -Master Drive Unit Parts 1.

2.

3.

4.

5.

6.

Drive End Head Bearing Snap Ring Field Coil Kit Fan Armature Assembly

Sheet 3: Electrical System 7. Brush 8. Brush Spring 9. Brush Box and Plate 10. Lead Arm Kit 11. Bearing 12. Wavey Washer 13. C.E. Head 14. Brush Cover Plate 6. If field coil must be replaced, remove pole shoe screws and terminal screws, if necessary, and remove field coils.

7. Inspect all components and the brushes. Replace as necessary. Refer to BRUSH REPLACEMENT in this section.

8. Using compressed air, blow out motor. Thoroughly clean and replace any worn parts.

9. Reverse steps above to assemble. Make sure armature turns freely with a few thousandths end play.

POWER STEERING MOTOR -REMOVAL AND INSTALLATION 1. Disconnect the battery. Open the drive unit compartment doors.

2. Remove, identify and disconnect the power cables.

3. To service the power steering pump, remove the mounting screws and nuts retaining the motor to the speed reduction gear bolt. Remove the motor from the truck as a complete unit.

4. Reverse the above steps to install the motor.

BRUSH REPLACEMENT -POWER STEERING MOTOR CAUTION: These motors should be disassembled in an extremely clean area free of any ferrous metal chips as the magnet pole pieces will attract them and cause serious damage to motor.

1. Disconnect battery. Open drive unit compartment doors. Remove the drive unit compartment cover.

2. Match mark the commutator end head and the stator assembly.

3. Remove the socket head thru bolts. Remove the commutator end head and bearing.

4. Remove the brushes. Inspect the brushes and springs.

5. Reverse the above steps to assemble.

POWER STEERING MOTOR-DISASSEMBLY AND ASSEMBLY 1. Remove the power steering motor. See POWER STEERING PUMP-REMOVAL AND INSTALLATION. 2. Mark both end heads and stator assembly to ensure proper alignment at assembly. Remove the socket head thru bolts and remove commutator end head and bearing.

3. Loosen hex screws and washers retaining the brushes. Remove the brush set and brush spring. Check nuts and jumper bar from terminals.

4. Remove drive end head and bearing.

5. Remove brush ring assembly. Remove armature and shaft assembly from stator assembly.

6. Use compressed air to clean armature, stator and end heads. Inspect all components. Replace all defective or worn parts.

7. Reverse above steps to assemble.

Sheet 3: Electrical System

Figure 3-33 -Steering Motor-W/O Wire Guidance 1. ARMATURE 2. FAN 3. BOLT 4. DRIVE END PINION 5. FAN COVER 6. BEARING 7. KEY 8. ROLL PIN 9. STATOR 10. COMMUTATOR END HEAD 11. BRUSH SET 12. NUT 13. SPRING WASHER 14. RETAINING RING

Sheet 3: Electrical System

Figure 3-34 -Steering Motor-W/ Wire Guidance

Figure 3-35 -Wiring Schematic

Sheet 3: Electrical System

Figure 3-35 -Wiring Schematic (continued)

Sheet 3: Electrical System

Figure 3-35 -Wiring Schematic (continued)

Sheet 3: Electrical System

Figure 3-36 -Wiring Diagram

Sheet 3: Electrical System

Figure 3-36 -Wiring Diagram(Continued)

Sheet 3: Electrical System

Figure 3-36 -Wiring Diagram (Continued)

Sheet 3: Electrical System

Figure 3-37 -Options Diagram

Sheet 3: Electrical System

Figure 3-38 -Wiring Schematic - Wire Guidance

Sheet 3: Electrical System

Figure 3-39 -Wiring Schematic -Wire Guidance (Continued)

Sheet 3: Electrical System

Figure 3-40 -Wiring Schematic - -Wire Guidance

Sheet 3: Electrical System

Figure 3-41 -Wiring Diagram -Wire Guidance

Sheet 3: Electrical System

Figure 3-42 -Wiring Diagram -Wire Guidance (Continued)

Sheet 3: Electrical System

Figure 3-43 -Wiring Diagram -Wire Guidance (Continued)

Sheet 3: Electrical System

Figure 3-44 -Options Diagram -Wire Guidance

Sheet 4: Drive Unit

DRIVE UNIT This section has a description and the repair and adjustment procedures for the parts of the master drive unit (MDU). The final drive ratio of the MDU used in the OS EB model is 14.9:1. The traction motor, steering and brake repair procedures are in separate sections. The main parts of the MDU are the case, pinion (motor) and large gear set, the pinion and spiral bevel gear set, bearings, and the axle and wheel. The large ball bearing for steering is part of the upper housing of the MDU. The traction motor fastens to an adapter ring that is attached to the lift truck frame. This adapter ring is part of the large ball bearing and allows the MDU to turn on the axis of the traction motor. The traction motor does not turn with the MDU. NOTE: The manufacturer recommends draining and refilling the drive unit oil after the first 500 hours of use on all new trucks. See Section 2 -LUBRICATION INSTRUCTIONS.

DESCRIPTION Six capscrews fasten the large ball bearing and MDU to the frame. The bearing lets the MDU turn for steering. There is a small helical pinion on the motor armature shaft. This pinion turns a large helical gear attached to the bevel pinion shaft in the MDU. The bevel pinion shaft turns the bevel gear attached to the axle shaft to turn the drive wheel.

The brake is fastened to the top end of the motor shaft to stop rotation of the shaft. The brake action works through the gears to stop the unit.

REPAIR REMOVAL CAUTION: The capscrews used to fasten the Master Drive Unit (MDU) and traction motor are all !M metric. Do not damage them using the wrong tools.

1. Move the steering wheel so that the drive wheel is in a position for straight travel.

2. Disconnect and remove the battery. See Section 2 GENERAL TRUCK AND LUBRICATION, CHANGING THE BATTERY 3. Open the drive unit compartment doors. Fasten the doors so that they are fully open. Put a pan under the MDU drain plug and remove the drain plug. Afterthe oil has completely drained, install the drain plug. Tighten the drain plug to 22 Nm (16 Ibf ft) torque.

4. Tag and disconnect the power cables of the traction motor. Fasten the cables in a location to prevent damage during motor removal.

5. Disconnect the wires to the brake assembly.

6. Make an identification mark on the motor housing and the frame weldment for correct motor alignment during installation. Remove the six capscrews and lockwashers retaining the flange of the traction motor to the MDU upper housing.

WARNING: The traction motor is heavy. Be sure that all lifting devices (hoists, cables, chains, !M slings, etc.) are suitable and of adequate capacity to lift the traction motor. The traction motor can weigh approximately 40 kg (85 Ibs).

7. Use a sling around the traction motor and an overhead crane to carefully lift the traction motor. Do not damage the drive gear on the motor shaft or the brake assembly on the top of the motor. Position the motor on its side so that the gear and the brake assembly are not damaged.

8. Loosen the locknut at the chain anchor for the steering chain. Remove the capscrew at the chain anchor. Put a mark on the MDU for the location of the pin that fastens the chain anchor to the sprocket. Remove the pin.

Carefully remove the chain anchor and chain from the sprocket.

WARNING: The lift truck is heavy. Be sure that all lifting devices (hoists, cables, chains, slings, etc.) !M are suitable and of adequate capacity to lift the lift truck. The lift truck can weigh approximately 3541 kg(7800lbs) empty.

9. Carefully put a sling under the lift truck frame. Position the sling near the MDU on the mast side of the MDU. Attach the sling so that it will not slip when the lift truck is raised. Do not damage the guidance sensor if the

Sheet 4: Drive Unit lift truck has wire guidance.

WARNING: If the MDU falls, it can cause an injury. Hold the MDU vertical to prevent it from falling.

10. Remove the six capscrews and lockwashers that fasten the adapter ring and MDU to the frame or axle plate.

11. Hold the MDUandraisethelifttruckframesothattheMDU is free. Carefully lower the MDU to the floor and move the MDU from under the lift truck. Lower the lift truck frame onto blocks.

DISASSEMBLY See Figure 4-1 and Figure 4-2.

CAUTION: Failure to completely straighten the staked portion ofthe nut priorto removal can cause damage to the shaft threads.

CAUTION: The capscrews and nuts used on the MDU are all metric. Do not damage them using the wrong tool.

NOTE: Before disassembling the drive unit make certain the work area is clean and all the necessary tools are available. The nuts retaining the drive axle and upper gear on the pinion shaft are staked in place and the staked portion must be completely removed before attempting any disassembly.

1. Remove the wheel nuts and the drive/steer wheel.

2. Remove the nine capscrews that fasten the lower housing to the upper housing. Remove the four capscrews inside the upper housing. See Figure 4-1. There are also two capscrews inside the case that are secured with washers and nuts on the opposite side of the upper housing. Make certain to remove the capscrews, lockwashers and nuts before attempting to separate the upper housing from the lower housing.

3. The upper housing is retained to the lower housing with two dowel pins. Use a plastic hammer against the lower portion of the upper housing to separate the upper housing from the lower housing. Carefully slide the upper housing for clearance between the upper housing and helical gear. Remove the upper housing.

CAUTION: The helical gear and pinion shaft assemblycan only be removed afterthe bevel gear and axle shaft have been removed from the driveunit lower housing.

4. Remove the capscrews retaining the drive unit cover. Remove the drive unit cover.

5. Install two wheel nuts onto the wheel bolts. Position a piece of wood or bar between the nuts to hold the drive axle stationary while removing the special capscrew retaining the bevel gear to the axle shaft. Remove the special capscrew (24 mm) and the special washer.

WARNING: If the MDU falls, it can cause an injury. Hold the MDU vertical to prevent it from falling.

WARNING: Toxic vapors may be generated by heating the axle shaft to remove the Loctite@. Wear a protective mask during this operation. Use gloves to remove the bevel gear if it has been heated.

CAUTION: Be careful not to damage the threads or splines on the axle shaft.

NOTE: The bevel gear is secured to the axle shaft using Loctite®270. It may be necessary to use a welding torch to heat the bevel gear to 100 to 120°C (212 to 248°F) to free the bevel gear from the axle shaft.

6. Use a strap wrench or place a wood wedge under the helical gear to keep the gear from rotating. Remove the nut retaining the helical spur gear. Use a gear puller to remove the helical gear from the pinion shaft. Carefully remove the pinion shaft and bearing cone from the lower housing. Use a plastic hammer, if necessary. Remove the spacer bushing from the pinion shaft.

7. Use a copper mandrel and a plastic hammer to drive the axle shaft outofthelower housing. Remove the bevel pinion out of the lower housing.

Sheet 4: Drive Unit

Figure 4-1 -Separating Upper and Lower Housing 1.

2.

3.

4.

5.

UPPER HOUSING CAPSCREWS INSIDE TOP CASE HOUSING CAPSCREWS DOWEL

Sheet 4: Drive Unit

Figure 4-2 -Master Drive Unit Parts 1.

2.

3.

4.

5.

6.

7.

TRACTION MOTOR CAPSCREW LOCKWASHER NUT LOCKWASHER PINION O-RING

Sheet 4: Drive Unit 8. CAPSCREW 9. LOCKWASHER 10. CHAIN BLOCK 11. CAPSCREW 12. NUT 13. CHAIN TENSIONER 14. CONNECTING LINK 15. CHAIN 16. CAPSCREW 17. CENTERING RING 18. CAPSCREW 19. WASHER 20. NUT 21. CAPSCREW 22. CAPSCREW 23. CAPSCREW 24. DOWEL PIN 25. PINION GEAR 26. LOCKNUT 27. HELICAL GEAR 28. BEARING 29. SHIMS 30. DRAIN PLUG 31. SEAL RING 32. CAPSCREW 33. COVER 34. AXLE SHAFT 35. WHEEL BOLT 36. BEARING 37. SHIMS 38. SEAL RING 39. THREAD PROTECTION SEAL 40. CAPSCREW 41. DISK 42. RING GEAR AND PINION SHAFT 43. BEARING 44. SHIMS 45. LOWER HOUSING 46. LUBE FITTING 47. BREATHER VALVE 48. PLUG -OIL FILL 49. SEAL RING 50. UPPER HOUSING 51. WHEEL/TIRE ASSEMBLY 52. LUG NUT

CAUTION: Keep all shim sets together and labeled for correct location and installation during assembly NOTE: If the bevel pinion and gear set will NOT be replaced, the same shim sets can be used during assembly.

Adjustment will not be necessary.

8. If necessary, remove the bearing cones from the axle shaft, from the bevel gear and from the bevel pinion shaft.

To remove the bearing cone from the axle shaft it is necessary to cut the bearing cage, then open the cage and remove the rollers. Use a puller to remove the cone from the axle shaft.

9. Remove the bearing shield from the lower housing using a plastic hammer. See Figure 4-3.

10. If necessary, remove the motor nut, lockwasher, bevel pinion and key from the motor shaft. Remove the O-ring from the motor.

Sheet 4: Drive Unit

Figure 4-3 -Removing Bearing Shield 11. Remove the wheel bolts from the axle shaft, using a hydraulic press, if necessary.

12. If necessary, remove each of the bearing cups. Use a puller or copper mandrel and a plastic hammer. Do NOT damage or lose the shims between the cups and the bore in the case. Keep each set of shims together and separate from the other sets of shims. Put a label on each set so that the sets can be installed in the correct position during assembly. Measure the distance between the edge of the case and the inner seal ring at the axle bore. The replacement seal ring MUST be installed in the same position as the old seal. Remove the seal ring.

ASSEMBLY WARNING: Cleaning solvents can be flammable and toxic, and can cause skin irritation. When using cleaning solvents, always follow the recommendations of the manufacturer. Wear eye protection.

1. Clean all components thoroughly. Remove all traces of Loctite®. Use Loctite®Fast Cleaner No. 706 to remove Loctite® from the lower housing in the area where the thread protecting shield had been located. Spray the cleaner from a distance of approximately 30 cm (0.50 in), while holding the can upright. Allow the cleaner to work, then thoroughly remove the dissolved dirt from the lower housing using a clean cloth. Spray the surface with the cleaner again and allow to air dry.

2. Check all parts for damage or cracks. Replace all worn or damaged parts. When assembling the drive unit use all new stake nuts, O-rings and seals.

CAUTION: The axle and gear assemblies are installed and removed several times during this !M procedure. Be careful during installation so that the bearing seal is not damaged.

NOTE: The helical pinion and gear and the bevel pinion shaft and bevel gear are matched sets and MUST be replaced as sets. When replacing the gear sets, always replace the tapered roller bearings. The inner bearings and outer races MUST be from the same manufacturer. Lubricate the bearings with clean transmission oil prior to assembly.

NOTE: Assembly of the drive unit requires the use of a standard micrometer, torque wrench and a dial indicator. The use of other special tools is recommended by the manufacturer of the drive unit.

NOTE: The large ball bearing is part of the upper housing. The upper housing and the ball bearing are replaced as a unit.

Bevel Pinion Shaft Installation See Figure 4-2, Figure 4-5 and Figure 4-7.

This procedure has the necessary steps needed to install the bevel pinion shaft. All of these steps are necessary if a

Sheet 4: Drive Unit replacement bevel pinion shaft and gear set or a replacement lower case are needed. Normally, it is not necessary to replace the lower case or helical gear set.

If the original bevel gear set will be installed in the same lower case, use the original shim sets (x) and (y). Install the shim sets, bearing, bevel pinion shaft, helical pinion and gear and special nut. Check the bearing clearance as described in Step g.

If only the bevel gear set is replaced, use the number (*) to find the correct shim set (x). If the new number is smaller than the old number, remove shims. If the old number is larger, add shims. Add or subtract shims equal to the difference between the numbers. Do NOT use damaged or distorted shims.

EXAMPLE: The old number 74.25 minus the new number 74.15 will make removing shims 0.1 mm (0.004 in) thick necessary.

If this method of finding the correct set is used, it is NOT necessary to do Steps b. through d. Do Steps a. and e.

Through g.

Use all of the following Steps to assemble, adjust and install a NEW bevel pinion (if you do not have one of the above numbers) or the original bevel pinion shaft in a NEW case.

NOTE: There are two numbers on each of the two parts of the bevel gear set. One number on each part is the set number. These numbers MUST be the same. The other number on the bevel gear is the gear clearance number.

The other number on the bevel pinion is the dimension "B" value. Check that the numbers are correct.

Figure 4-4 -Bearing and Shim Location 1. UPPER PINION BEARING RACE 2. LOWER PINION BEARING RACE 3. INNER AXLE SHAFT BEARING RACE 4. OUTER AXLE SHAFT BEARING RACE 5. UPPER PINION BEARING SHIMS 6. LOWER PINION BEARING SHIMS 7. INNER AXLE SHAFT SHIMS 8. OUTER AXLE SHAFT SHIMS 9. INNER SEAL RING 10. BEARING SHIELD

Sheet 4: Drive Unit Install the bevel pinion shaft as follows: a. Make a bushing to fit the bore for the lower pinion shaft bearing. The bushing O.D. will be 51.5 mm (2.03 in).

Bushing (2) must be 67.5 mm (2.66 in) long. b. Install the bushing in the bore. To find the correct thickness for shim set "x", it is necessary to know the case dimension E. To find the case dimension E, use the formula: E=L-F+d/2 L = bushing length F = the difference between the bearing bore for the axle and the end of the bushing. See Figure 4-5. d/2 = 44.45 mm (1.75 in) c.

Measure the dimension F. See Figure 4-5. Subtract the value F from the length (L) of the bushing and add the value d/2. The result is dimension E.

d. The shim set thickness X for shim set "x" for the lower bearing is found as shown in Figure 4-5.

X = E -B -T E = the value found in Step c B = the number on the end of the pinion shaft T = the total thickness of the bearing e. Install the shim set "x" and press the bearing cup into the bore. Install the bearing cone and spacer on the pinion shaft. Install the pinion shaft in the case. f.

Install a piece of wood between the end of the pinion and the case to hold the pinion tightly in the bore. Do NOT install shims or bearing. Measure the distance between the top end of the spacer and the bottom of the bore for the bearing. This is distance C in Figure 4-5.

g. Measure the distance S between the edges of the bearing cup and cone. If the cup extends below the cone, the dimension S is negative (subtract). If the cone extends below the cup, the dimension S is positive (add). h. Add or subtract (Step g.) dimension S from dimension C. The result minus 0.02 mm (0.001 in) is the dimension X or the thickness of shim set "y" for the top bearing.

X (in mm) = C + or -S -0.02 mm. i.

Install the shim set "y", the bearing cup, bearing cone, helical gear and special nut. Use a press to install the bearing cup.

j.

Use a strap wrench or a piece of wood to keep the helical gearfrom turning and tighten the nut to 100 Nm (74 Ibf ft) torque. Do NOT use a punch to lock the nut at this time.

Bevel Gear Installation See Figure 4-6 and Figure 4-7.

1. Use a press to install the wheel bolts.

NOTE: When installing the wheel bolts, make certain that the flat side of the bolt collars face the center of the wheel shaft.

2. Install the seal ring on the wheel shaft. Install the cone on the axle shaft.

NOTE: After the proper backlash has been obtained, grease the seal ring and fill the outer bearing cone using Shell Alvania R3 grease prior to assembly.

3. Install the cone on the bevel gear using a press.

4. Do NOT install the inner seal ring until the bearing preload has been adjusted. Install the original shims under both the inner bearing cup and the outer bearing cup. Use a press to install both bearing cups in the case.

NOTE: Do NOT use damaged or distorted shims.

5. Carefully install the axle assembly in the case. Install the bevel gear on the axle assembly using the M16 capscrew and special washer.

6. Prevent the axle from turning. Tighten the M16 capscrew to 245 Nm (332 Ibf ft) torque. Tighten the special nut at the large gear to 60 Nm (44 Ibf ft) torque.

Sheet 4: Drive Unit 7. Check and adjust the backlash, tooth contact pattern and bearing clearances BEFORE continuing. See CHECKS AND ADJUSTMENTS. 8. After the proper backlash and tooth contact pattern has been established, remove the bevel gear, the bearing cups, and the axle assembly.

9. Coat the seat of the thread protecting seal with Loctite No. 270. Press the shield on the lower housing as far as possible. Thinly coat the radial shaft seal with Loctite® No. 574. Install the inner seal into the lower housing. The inner seal, when properly installed, should be 1.8+0.5 mm (0.071 +0.02 in) below the bottom edge of the outer bearing bore. See Figure 4-6. Fill the inner seal ring and the cone on the axle shaft with Shell Alvania R3 grease.

Figure 4-5 -Installing Bevel Pinion Shaft 1. BEVEL PINION SHAFT 2. SPACER 3. SPECIAL BUSHING 4. LOWER CASE 5. LOWER BEARING 6. SHIM SET "X" 7. SHIM SET "Y" 8. UPPER BEARING 9. BEARING CUP 10. BEARING CONE

Sheet 4: Drive Unit

Figure 4-6 -Inner Seal Installation 10. Install the shims, outer bearing cup and the axle shaft. Apply Loctite® 270 to the internal splines of the bevel gear. Install the bevel pinion on the axle shaft. Remove any excess Loctite from the bevel gear using a clean cloth. Install the M16 capscrew and special washer. Tighten the M16 capscrew to 245 Nm (332 Ibf ft) torque.

NOTE: If the tapped holes in the bottom of the lower housing extend through the housing, it is recommended that the capscrews are completely sealed with Loctite®to prevent oil from leaking from around the threads.

11. Use Loctite® 574 on the cover. Apply one drop of Loctite 243 on each of the cover capscrew threads. Install the cover. Tighten the cover capscrews to 9.5 Nm (7 Ibf ft) torque.

12. Use Loctite® 574 to install the upper housing on the lower housing. Make sure the upper housing is aligned correctly and use a punch to install the two dowels, if removed. See Step 3 of the DISASSEMBLY procedure.

Install the capscrews to retain the upper housing to the housing. Tighten the 8 mm capscrews to 23 Nm (17 Ibf ft) torque. Tighten the 10 mm capscrews to 46 Nm (34 Ibf ft) torque. Install the alien head capscrews and the washers and nuts. Tighten the nuts to 23 Nm (17 Ibf ft) torque.

NOTE: To replace the drive tire on the wheel, the wheel must be pressed out of the tire rim. See Section 2 -HOW TO CHANGE THE DRIVE/STEER TIRE. 13. Install the wheel and the lug nuts. Tighten the nuts in a cross pattern to one-half the torque value specified in Section 2. Tighten the lug nuts again using the cross pattern to obtain the proper torque.

Sheet 4: Drive Unit

Figure 4-7 -Installing Bevel Gear Set 1. LOCKNUT 2. HELICAL GEAR 3. BEARING 4. SHIMS 5. LOWER HOUSING 6. SHIMS 7. BEARING 8. BEVEL PINION GEAR 9. DISK 10. CAPSCREW 11. SHIMS 12. BEARING 13. BEVEL PINION SHAFT 14. CAPSCREW 15. COVER 16. DRAIN PLUG 17. THREAD PROTECTION SEAL 18. INNER SEAL 19. SHIMS 20. BEARING 21. AXLE SHAFT 22. WHEEL BOLT 23. HELICAL PINION

CHECKS AND ADJUSTMENTS Backlash and Tooth Contact Pattern See Figure 4-8 and Figure 4-11.

CAUTION: The axle and gear assemblies are installed and removed several times during this procedure. Be careful during installation of the axle so that the bearing seal is not damaged.

This backlash is the clearance between the teeth of the bevel gear and the teeth of the pinion. Use a dial indicator to

Sheet 4: Drive Unit measure the clearance. See Figure 4-8. Put the dial indicator in a position so that the sensor touches a tooth of the bevel gear. Install a wood wedge under the large gear at the top of the MDU to keep the gear and pinion from moving. Move the bevel gear in the direction awayfrom the sensor of the dial indicator. Adjust the dial indicator for a zero reading. Move the gear toward the dial indicator and read the backlash. The backlash must be 0.1 to 0.15 mm (0.004 to 0.006 in).

Figure 4-8 -Checking Backlash 1. SPIRAL BEVEL GEAR 2. DIAL INDICATOR 3. WOOD WEDGE If the backlash is too much, the bevel gear must move toward the pinion. If the backlash is not enough, the bevel gear must move away from the pinion. The bevel gear is moved in the correct direction by adding or removing shims under the bearing cup. The shims for the shim set are available in the following thicknesses: 0.1 mm, 0.15 mm, 0.3 mm and 0.5 mm.

The tooth contact pattern must also be correct. Remove the wood wedge and check the tooth contact pattern as shown in Figure 4-11. Adjust the position of the bevel gear for the best tooth contact pattern and the correct backlash.

Axle Shaft Bearing Clearance See Figure 4-9.

CAUTION: The axle and bevel gear assemblies are installed and removed several times during this procedure. Be careful during installation of the axle so that the bearing seal is not damaged.

The correct bearing clearance for the bevel pinion and bevel gear is marked on the edge of the bevel gear. The adjustment range is f 0.03 to 0.07 mm (f 0.001 to 0.003 in). Carefully install the axle assembly and bevel gear in the case. Use the original shims under the special washer. Tighten the capscrew to 100 Nm (74 Ibf ft) torque.

Remove the capscrew and special washer. Measure the thickness of the shim set. Use a soft hammer to tap the end of the axle to move it approximately 1 mm (0.04 in). Add 0.1 mm (0.004 in) of shim to the shim set. Install the special washer and capscrew again. Tighten the capscrew as before.

Use a dial indicator to measure the bearing clearance. See Figure 4-9. Put the dial indicator in a position so that the sensor touches the flat surface of the special washer on the spiral bevel gear. Make a mark on the gear as a measurement point. Move the bevel gear in one direction (approximately 180°) while pushing on the gear. Adjust the dial indicator for a zero reading at the measurement mark. Move the gear in the opposite direction while pulling on the gear. Read the clearance on the dial indicator at the measurement mark. If the clearance is not as shown on the edge of the gear, adjust the clearance. Add or remove shims between the special washer and the gear for the value marked on the edge of the gear. There will be no noticeable clearance when the adjustment is correct, but it will be possible to rotate the axle by hand.

Sheet 4: Drive Unit

Figure 4-9 -Checking Bearing Clearance 1. SPIRAL BEVEL GEAR 2. DIAL INDICATOR 3. SPECIAL WASHER

Trunnion Bearing The transmission upper housing must be replaced if: a. The sealed cover plate on the trunnion bearing has separated. b. The trunnion bearing is difficult to turn or binds. It is not possible to replace the outer race and/or balls. c.

The maximum bearing clearance is exceeded.

To check the bearing clearance, clamp the upper housing onto a level assembly table. Install three eye bolts into the outer race of thetrunnion bearing. Rotatethe bearing several times. Install a cable in each eye bolt.

Position three dial gauges on the trunnion bearing and set the gauge dials to "zero". Mark the position of one dial gauge on the trunnion bearing with a marking pen. See Figure 4-10.

Using a lifting device and a spring balance, raise the upper housing with approximately 50 kg (110 lb) of force.

Rotate the trunnion bearing several times and position at the mark again. The recommended maximum bearing clearance is 0.03 mm (0.0012 in). If the bearing clearance is more than the recommended clearance, the trunnion bearing and upper housing must be replaced.

Sheet 4: Drive Unit

Figure 4-10 -Checking Trunnion Bearing INSTALLATION WARNING: The lift truck is heavy. Be sure that all lifting devices (hoists, cables, chains, slings, etc.) are suitable and of adequate capacity to lift the lift truck. The lift truck can weigh approximately 3541 kg(7800lbs) empty.

1. Carefully put a sling under the lift truck frame on the mast side of the MDU. Do not damage the guidance sensor if the lift truck has wire guidance.

2. Lift the frame for clearance to slide the MDU under the frame. Temporarily install blocks under the frame to prevent lowering.

3. Move the MDU into approximate alignment under the frame.

4. Hold the MDU in the vertical position through the hole in the plate. Do NOT put any part of your body between the MDU and the frame or axle plate. Carefully raise the frame and remove the blocks. Carefully lower the frame and align the capscrew holes in the large ball bearing, adapter ring and the frame.

5. Install the six capscrews and lockwashers that fasten the adapter ring and MDU to the frame. Use a cross pattern to slowly tighten the capscrewstoapproximately25 Nm (341bfft) torque. Make sure the large ball bearing and adapter ring are in the correct position around the complete circumference. Use the cross pattern to tighten the capscrews to 68 Nm (50 Ibf ft) torque.

WARNING: The traction motor is heavy. Be sure that all lifting devices (hoists, cables, chains, slings, etc.) are suitable and of adequate capacity to lift the traction motor. The traction motor can weigh approximately 40 kg (85 Ibs).

6. If the pinion gear on the motor shaft was removed, install the key, gear, lockwasher and nut. Tighten the nutto 54 Nm (40 Ibf ft) torque. If an impact wrench is used, make sure it does not tighten the nut to more than the correct torque.

7. Install a new O-ring on the motor using O-ring lubricant.

8. Use an overhead crane and a sling to lift the traction motor. Carefully align and lower the traction motor onto the MDU adapter ring. Do NOT damage the pinion gear on the motor shaft, the large gear of the MDU or the brake assembly. Make sure that the motor is aligned properly before lowering it into the upper housing.

9. Install the three capscrews and lockwashers. Tighten the capscrews to 20 Nm (15 Ibf ft) torque.

Sheet 4: Drive Unit 10. Connect the power cables to the motor terminals.

11. Connect the wires to the brake assembly.

12. Make sure the MDU is in the position for straight travel with the tire to the left of the case (facing MDU). Carefully install the steering chain. Use the pin to install the chain anchor on the adapter ring. Use the capscrew to fasten the two chain anchors together. Adjust the steering chain and steering potentiometer. See Section 6 -STEERING SYSTEM and Section 3 -ELECTRICAL SYSTEM for additional information.

13. Lubricate the large ball bearing using the recommended grease listed in Section 2 and adding the grease through both fittings. Slowly rotate the MDU while filling the fittings with grease. A dry bearing will take approximately 55 g (0.12 lb) of grease to fill the bearing completely.

14. Lower the lift truck to the floor. Fill the MDU to the level/fill plug using the recommended oil listed in Section 2.

Add the oil slowly. The oil must go through the bearings to the lower part of the MDU. Fill until the oil just starts to run out. Install the plug and tighten to 22 Nm (17 Ibf ft).

15. Close the drive unit compartment door. Install and connect the battery.

Sheet 4: Drive Unit

Figure 4-11 -Gear Tooth Contact Pattern TROUBLESHOOTING

Sheet 4: Drive Unit

Sheet 5: Brake System

BRAKE SYSTEM GENERAL This section provides the description and repair procedures for the electric brake assembly.

DESCRIPTION AND OPERATION The electric brake is installed on the top of the drive motor. The brake assembly has a coil, a mounting flange, an armature, a hub, and rotor, with two function surfaces. The coil is fastened to the housing of the drive motor. The hub is installed on the shaft of the drive motor. The rotor is installed between the armature and mounting flange. The rotor engages the armature and mounting flange, and rotates with the shaft of the motor.

When the operator releases the brake switch on the operator platform by removing his foot, the brake is automatically applied. When the brake is applied, springs push the armature plate against the rotor and push the rotor against the mounting flange. The operator must engage the brake switch to release the brake. The brake switch energizes the coil. The coil pulls the armature away from the rotor.

Several conditions can cause application of the brake because the brake is used on several different units. These are the conditions that apply the brake: •

Brake switch is released.

•

Key switch is turned to OFF.

•

Power disconnect circuit is activated.

•

The automatic shutoff circuit is activated.

•

A lift chain is slack (slack chain switch activated).

•

A side gate is up (side gate switch activated).

BRAKE SWITCH The brake switch assembly is located in the floor of the operator's platform.

NOTE: If the lift truck must be moved without battery power, the brake can be manually released. There are two holes with 1/4-20 UNC threads in the back plate. Install capscrews in the holes. Use the capscrews to push the armature plate away from the friction disc.

WARNING: When the brake is manually released, put a "DO NOT OPERATE" tag on the steering wheel.

Sheet 5: Brake System

Figure 5-1 -Electric Brake 1.

2.

3.

4.

5.

6.

7.

8.

9.

MOUNTING FLANGE ROTOR HOLLOW SPACER ARMATURE SPRING HUB COIL WASHER CAPSCREW

ELECTRIC BRAKE-REMOVAL AND DISASSEMBLY WARNING: Disconnect the battery connector before starting any repairs.

1. Disconnect the battery connector.

2. Disconnect the wiring harness connector from coil connector.

3. Remove the three capscrews and washers that secure the brake to the mounting flange.

4. Carefully remove the coil, springs, armature, rotor, hub, and hollow spacers from the mounting flange.

5. Remove the mounting flange from the motor.

Sheet 5: Brake System

Figure 5-2 -Electric Brake 1.

2.

3.

4.

5.

6.

7.

8.

9.

MOUNTING FLANGE ROTOR HOLLOW SPACER ARMATURE SPRING HUB COIL WASHER CAPSCREW

ELECTRIC BRAKE-ADJUSTMENT New brakes are pre-adjusted at the factory to the correct .012 in. (.3mm) air-gap (distance between coil and armature). See Figure 5-2. As the brakes wear, the air-gap will increase. When the air-gap reaches two or three times the specified value, it should be adjusted. The air-gap should also be adjusted whenever the rotor replaced or a replacement brake assembly has been installed.

1. Loosen the three capscrews that secure the brake assembly to the mounting flange.

2. Turn the hollow spacers counterclockwise two or three revolutions.

3. Using a measuring device between the coil and armature, set the air-gap slightly smaller than the desired air-gap, .010 in. (.25 mm) by turning the capscrews clockwise.

NOTE: The air-gap is to be checked between the bolts (in the middle), not at the bolts. The air-gap adjustment is made when turning the capscrews, not the hollow spacers.

4. Turn the hollow spacers clockwise until they are snug against the mounting flange. The air-gap should now be at the desired .012 in. (.3 mm).

5. Check that the final setting is correct.

6. Use adhesive sealant on the capscrews.

NOTE: Acceptable adhesive sealants include those below: Loctite Corporation No. Felt-pro Inc. Saf-T-Lok Chemical Corp

290 Pro-Lock Saf-T-Lok S90

7. Tighten the three capscrews. Torque to 33 Ib \ ft (45 Nm).

8. Connect the wiring harness connector to the coil connector.

Sheet 5: Brake System 9. Connect the battery connector.

ELECTRICAL BRAKE-ASSEMBLY AND INSTALLATION 1. Install the mounting flange on the motor.

2. Install the key and hub on the motor shaft.

3. Install the washer and nut. Torque the nut to 80 Ib \ ft (12 Nm). Loosen the nut to the first alignment position and install a new cotter pin.

4. Install the springs between the coil and armature.

5. Install the hollow spacers through the armature engaging the screw holes in the coil. Turn the hollow spacers clockwise two or three revolutions.

6. Place the three washers on the capscrews and install them through the coil into the hollow spacers.

7. Install the brake assembly onto the mounting flange.

8. Make the air-gap adjustment. See Electrical Brake Adjustment.

BRAKE SWITCH-REMOVE AND REPLACE WARNING: Disconnect the battery connector before starting any repairs The brake switch assembly is in the floor of the operator's platform. Remove the cover of the assembly to get access to the switch. Put labels on the wires. Make sure the labels accurately describe the connections on the switch.

Disconnect the wires and remove the switch.

When a switch is installed, connect the wires according to the labels. Figure 5-3 shows typical connections. If necessary, see the wiring diagrams found in Section 3.

Figure 5-3 -Brake Switch 1.

2.

3.

4.

5.

6.

7.

SCREW COVER SPRING SCREW NUT SWITCH ASSEMBLY SPRING

Sheet 5: Brake System TROUBLESHOOTING

Sheet 6: Steering System STEERING SYSTEM GENERAL This section contains procedures for adjustment, repair and troubleshooting of the Electric Power Steering System.

The system controls the steer motor used to turn the Master Drive Unit. The lift truck is steered by turning the Master Drive Unit.

There are three Electric Power Steering Systems available: the standard system called Tach Steer Generator Steering System (TGS), the optional Smart Steering System and the Wire Guidance Steering System. This section covers the standard TGS System and the optional Smart Steering System only.

NOTE: This section is NOT applicable to lift trucks with the optional Wire Guidance Steering System. See SECTION 7 WIRE GUIDANCE for checks, adjustments, and repairs to the steer system of trucks equipped with the Wire Guidance Steering System.

DESCRIPTION The Electric Power Steering system is comprised of the following components: a. Steering handle (Smart Steer System) or steering wheel (TGS System) b. Command potentiometer (Smart Steer System) or the tach generator (TGS system) c.

Feedback potentiometer

d. Steering system wire harness e. Electronic Control Module (ECM) f.

Lift truck battery

g. Steer motor h. Steering sprocket and chain The TGS system has a steering wheel coupled to a belt-driven tach generator. The steering wheel does NOT automatically return to the center position.

The Smart Steering System has a steering handle that returns to the center position when released. The handle moves 100°each side of center for the full range of steering control.

The steering wheel and tach generator for the TGS system are located in the operator's compartment. The steering handle and command potentiometer for the Smart Steer system are located in the operator's compartment. The Electronic Control Module and steer motor are in the motor compartment beside the master drive unit. The feedback potentiometer is connected to the steer motor below the steer sprocket. The steering chain connects the steer sprocket at the gear motor to the sprocket of the master drive unit. The Electronic Control Module is also located in the steer motor compartment.

The command potentiometer attached to the steering handle provides a signal to the Electronic Control Module corresponding to the operator input. Similarly, the tach generator coupled to the steering wheel on the optional TGS system provides a signal to the Electronic Control Module corresponding to the operator input. The Electronic Control Module processes the signal to a ascertain the steer angle selected by the operator.

The feedback potentiometer is connected to the steer motor. The feedback potentiometer provides a signal to the Electronic Control Module that corresponds to the position of the master drive unit.

The signal from the command potentiometer (or tach generator) and the signal from the feedback potentiometer are sent simultaneously to the Electronic Control Module. If the master drive unit is not at the operator-selected angle, the Electronic Control Module provides electrical output to the steer motor.

The steer motor is coupled to the master drive unit with a sprocket and chain. The electrical output to the steer motor causes the motor to rotate the sprocket and chain and turn the master drive unit. As the master drive unit approaches the selected angle, the signal from the feedback potentiometer changes to instruct the Electronic Control Module to slow and then stop the rotation of the steer motor.

CHECKS AND ADJUSTMENTS

Sheet 6: Steering System General Do not make adjustments to a properly operating steering system.

WARNING: Do not operate a lift truck that needs adjustments or repairs. Report the need for adjustments or repairs immediately. If adjustment or repair is necessary, put a "DO NOT OPERATE" tag in the operator's area.

Remove the key from the key switch.

WARNING: Some of the checks and adjustments are done with the battery connected. Never have any metal on your fingers, arms or neck. During some checks or adjustments, the operator must move the lift truck. The person doing the adjustments must make the adjustments with the system energized. Make sure the operator does not move the lift truck to cause an injury.

CHECKS Three test points are provided for adjustment of the Electronic Control Module. TP1 is the feedback potentiometer input adjusted by P2. TP2 is NOT used in the tachometer steering system. TP3 is the analog and logic common.

Light Emitting Diodes (LEDs) 1 through 5, located on the Electronic Control Module circuit board, are used to indicate system faults.

Dipswitches CAUTION: The dipswitches are factory-set and should not need to be adjusted.

If the Electronic Control Module (ECM) is replaced or the settings of the dipswitches are inadvertently changed, see Figure 6-1 to set the position of the dipswitches to the factory settings.

On trucks equipped with the optional TGS steer system, an adjustment can be made to the settings of dipswitches 5, 6, and 7 to alter the sensitivity of the tach generator input scaling, if desired. Refer to Tach Generator Steering System - Sensitivity Adjustment in the ADJUSTMENTS section.

Figure 6-1 Dipswitches -Factory Settings

LED Indicators The Electronic Control Module continuously monitors the steering system. Problems detected by the Electronic Control Module are indicated by 5 LEDs. See Figure 6-2. These vehicles equipped with electric steering systems are designed to stop automatically when a fault occurs. The brake relay, located in the Electronic Control Module, applies the brake to stop the vehicle if a fault condition is detected.

Table 1 -LED Indicators

Sheet 6: Steering System

Figure 6-2 -Electronic Control Module Checking the Steering System for Correct Operation The Electronic Control Module check includes checks for the command potentiometer and the feedback potentiometer.

1. Open the motor compartment door. Move the key switch to the ON position and push the foot switch.

2. Make sure the battery has a corrected specific gravity of at least 1.250. To check the system for correct operation, move the steering handle or steering wheel from a full left turn position to a full right turn position. The master drive unit should move 85°to 95°in each direction from straight travel.

3. If the master drive unit moves less than 90°( t 5° ) in either direction, the steering is incorrectly adjusted or may have a mechanical problem. Refer to ADJUSTMENTS. 4. Check that the master drive unit moves through the full range of rotation in five seconds or less. The lift truck must be on smooth concrete with a fully charged battery and no load.

5. If the master drive unit requires greater than 5 seconds to move through the full range of rotation, check for a

Sheet 6: Steering System mechanical problem or defective Electronic Control Module.

Checking Slow Travel Speed NOTE: The slow travel speed is checked during the adjustment procedure. Refer to ADJUSTMENTS. Checking High Lift Traction Shutoff 1. Instruct the operator to raise the platform above 3810 mm (150 in).

2. The traction system should NOT operate with the operator platform above 3810 mm (150 in) unless the truck is equipped with the high lift travel-enable option. If the unit is so equipped, check that the traction system operates normally EXCEPT when the steering is set for 7°or more from center and the operator platform is above 3810 mm (150 in). If the steering is set for more than 7°and the operator platform is above 3810 mm (150 in), the traction system should NOT operate.

ADJUSTMENTS General NOTE: This section is NOT applicable to lift trucks with the optional Wire Guidance Steering System. See STEERING SYSTEM WIRE GUIDANCE II -SECTION 7 for checks and adjustments to the Wire Guidance Steering System.

Make sure the battery has a corrected specific gravity of at least 1.250. Move the lift truck to an open area where it can be driven in a straight line for a distance of at least 9 metres (30 ft).

NOTE: Do not make adjustments to a properly operating steer system. The following adjustments must be done in the order specified. Do not move the steering wheel or handle after it has been accurately centered unless instructed to move it in the following procedures.

Figure 6-3 -Tach Generator Steering

TACH GENERATOR STEERING SYSTEM Tach Generator Adjustment The tach generator is located at the steering mechanism in the instrument panel. Remove the screws at the top of the instru-ment panel. Tilt the panel to the open (down) position for access to the tach generator.

The tach generator does not require adjustment. Check the drive belt for proper alignment and verify that the belt is not excessively worn. Replace as required. See Figure 6-3.

Sensitivity Adjustment

Sheet 6: Steering System WARNING: Changing the sensitivity setting of the tach generator steering system alters the amount of operator effort required to steer the truck. Notify all affected operators that the truck may steer differently before operation. Use caution to avoid injury.

The sensitivity of the TGS steering system is adjusted by changing the position of dipswitches 5, 6, and 7. Do not change any other dipswitches. See Table 2.

Table 2 -Sensitivity Adjustment

Feedback Potentiometer Adjustment 1. Center the drive tire for straight travel.

2. Refer to Figure 6-5 to identify the feedback potentiometer. Unplug the connector from the feedback potentiometer.

3. Measure the resistance between wires 16 and 17. Mea-sure the resistance between wires 17 and 18.

4. Adjust the feedback potentiometer until the resistance val-ues measured in Step 3 are equal (.t 50 ohms). Adjust the po-tentiometer by loosening the retaining nut and moving the po-tentiometer body to attain the desired resistance readings. Tighten the retaining nut without moving the potentiometer body.

5. Attach the plug removed in Step 2 to the feedback poten-tiometer. Set the key switch to the "ON" position.

6. Measure the voltage across TP3 and TP1 on the Electron-ic Control Module circuit board by inserting the negative probe intoTP3 and the positive probe in TP1. Adjust potentiometer P2 on the Electronic Control Module circuit board to a value of 0 Volts DC (:t 0.05 VDC).

WARNING: During the following check, the operator must move the lift truck. Use caution to avoid injury.

7. Operate the lift truck in a straight line for at least 30 feet, making corrections with the steering wheel as necessary to keep the truck traveling in a straight line. At the end of the 30 feet, do not touch the steering wheel.

Adjust potentiometer P2 again as described in Step 6.

8. Repeat this procedure a minimum of 3 times to insure ac-curate potentiometer adjustment.

SMART STEERING SYSTEM Command Potentiometer Adjustment The command potentiometer is located at the steering mecha-nism in the instrument panel. See Figure 6-4. Remove the screws at the top of the instrument panel. Tilt the panel to the open (down) position for access to the potentiometer.

1. Set the key switch in the "OFF" position.

Sheet 6: Steering System 2. Unplug the connector from the command potentiometer. See Figure 6-4.

3. Use an ohmmeter to measure the resistance between wires 19 (black) and 20 (green). Measure the resistance be-tween wires 20 (green) and 21 (white).

Figure 6-4 -Tachometer Steering 1.

2.

3.

4.

5.

6.

7.

8.

STEERING WHEEL TACH STEER ASSEMBLY TACH STEER BRACKET SPACER TIMING BELT STEERING SHAFT STEERING KNOB ASSEMBLY SPROCKET

4. Adjust the command potentiometer until the resistance values measured in Step 3 are equal (.t50 ohms). Adjust the po-tentiometer by loosening the retaining nut and moving the po-tentiometer body to attain the desired resistance readings. Tighten the retaining nut without moving the potentiometer body.

5. Attach the plug removed in Step 2 to the command poten-tiometer.

6. Set the key switch to the "ON" position.

7. Measure the voltage across TP3 and TP2 on the Electron-ic Control Module circuit board by inserting the negative probe into TP3 and the positive probe in TP2. Refer to Figure 6-2. Ad-just potentiometer Pi on the Electronic Control Module circuit board to a value of 0 Volts DC (.t 0.05 VDC).

Feedback Potentiometer Adjustment CAUTION: Make sure the Smart Steering command potentiometer is properly adjusted before adjusting the feedback.

1. Center the tire and steer handle for straight travel. After the drive tire and handle are centered, do not adjust the steer handle again until specifically instructed to do so in this procedure.

2. Refer to Figure 6-5 to identify the feedback potentiometer. Unplug the connector from the feedback potentiometer.

3. Measure the resistance between wires 16 and 17. Measure the resistance between wires 17 and 18.

4. Adjust the feedback potentiometer until the resistance values measured in Step 3 are equal (.t50 ohms). Adjust

Sheet 6: Steering System the potentiometer by loosening the retaining nut and moving the potentiometer body to attain the desired resistance readings. Tighten the retaining nut without moving the potentiometer body.

5. Attach the plug removed in Step 2 to the feedback potentiometer.

6. Set the key switch to the "ON" position.

NOTE: If there are no steering changes within a 10 second period, the Electronic Control Module removes power to the steer motor. To restore power to the steer motor, cycle the key from the "ON" position to the "OFF" position, and then back to the "ON" position.

7. Measure the voltage across TP3 and TP1 on the Electronic Control Module circuit board by inserting the negative probe into TP3 and the positive probe in TP1. See Figure 6-2. Adjust potentiometer P2 on the Electronic Control Module circuit board to a value of 0 Volts DC (.t 0.05 VDC).

WARNING: During the following check, the operator must move the lift truck. Use caution to avoid injury.

8. Operate the lift truck in a straight line for at least 30 feet, without touching the steer handle. Adjust potentiometer P2 again as necessary to ensure the lift truck travels in a straight line within 152 mm (6 in.) in 9 meters (30 ft.).

9. To verify that the lift truck is traveling in a straight-line, install a pointer at the center of the front (master drive unit end) of the lift truck. Make a mark on the floor under the point of the pointer.

10. Operate the lift truck straightforward 5 meters (15 ft). Make a mark on the floor under the point of the pointer.

11. Operate the lift truck straightforward 5 more meters (15 ft). Make another mark on the floor under the point of the pointer.

12. Draw a straight line between the first and last marks. The center mark must be within 76 mm (3 in) of the line. If the center mark is within this specification, P2 is correctly adjusted. If the mark is NOT within the specification, adjust P2 until the trial is successful.

Sheet 6: Steering System

Figure 6-5 -Motor Mounting Assembly STEERING CHAIN ADJUST 1. Disconnect the battery connector. Open the motor compartment doors.

2. Position a straight edge (e.g. a thin piece of rigid material) against the steering chain between the sprockets.

Make sure the chain is tight on the opposite side of the sprockets.

3. Push on the chain at a point approximately halfway between the sprockets with a force of 9 to 12 kg (20-25 Ibs).

Measure the clearance between the straight edge and the chain. The clearance should not exceed 3.3 mm (0.13 in). See Figure 6-6.

4. Tighten the adjustment nut at the master drive unit sprock-et to obtain a maximum clearance of 3.3 mm (0.13 in) between the chain and straight edge. Do NOT tighten the chain to a clearance of less than 1.3 mm (0.05 in).

5. Close and fasten the motor compartment doors.

Sheet 6: Steering System

Figure 6-6 -Steer Chain Adjustment 1.

2.

3.

4.

5.

6.

MOTOR SPROCKET MDU STEERING CHAIN STRAIGHT EDGE ADJUSTING BOLT ADJUSTING NUT

REPAIR TACH GENERATOR STEERING SYSTEM Tach Generator Replacement 1. Disconnect the battery connector.

2. Remove the screw that fastens the steering wheel to the shaft of the steering mechanism. Remove the steering wheel.

3. Remove the screws at the top of the instrument panel. Tilt the instrument panel to the open position for access to the parts.

4. Disconnect the wire harness to the tach generator.

5. Remove the capscrews, washers and nuts retaining the tach generator to the steering wheel bracket.

6. Remove the tach generator drive belt.

7. Install the tach generator mounting bracket to the new tach generator.

8. Insert the tach generator in place and install the tach generator drive belt.

9. Install the capscrews, washers, and nuts that retain the tach generator mounting bracket to the steering wheel bracket.

10. Connect the wire harness to the tach generator.

11. Install the instrument panel and connect the battery connector.

SMART STEER STEERING SYSTEM

Sheet 6: Steering System Command Potentiometer Replacement 1. Disconnect the battery connector.

2. Remove the screw that fastens the steering handle to the shaft of the steering mechanism. Remove the steering handle.

3. Remove the screws at the top of the instrument panel. Tilt the instrument panel to the open position for access to the parts.

4. Remove the capscrews that fasten the steering mechanism bracket to the back of the instrument panel.

5. Remove the setscrew that fastens the shaft of the command potentiometer to the steering shaft. Remove the capscrew and nut that fasten the bracket for the command potentiometer. Remove the bracket and potentiometer. Remove the potentiometer from the bracket. Label the potentiometer wires for correct connections during installations.

6. Install the new command potentiometer, as required. Connect the wires of the command potentiometer.

7. Install the steering mechanism bracket to the back of the instrument panel.

8. Connect all wires disconnected during removal.

9. If the command potentiometer was replaced or the setting was changed, adjust the command potentiometer.

Refer to ADJUSTMENTS. Tighten the screw that fastens the potentiometer to the steering shaft.

10. Close the instrument panel and tighten the screws. Install the steering handle on the shaft of the steering mechanism. tighten the screw.

Feedback Potentiometer Replacement 1. Position the master drive unit for straight travel. Disconnect the battery connector.

2. Open the motor compartment door. Disconnect the electrical plug for the feedback potentiometer.

3. Loosen the setscrew that fastens the shaft of the potentiometer to the motor assembly. Remove the nut that fastens the potentiometer to the bracket. Remove the potentiometer.

4. Set the new feedback potentiometer for mid-range. Install the new potentiometer on the bracket. Install the nut to fasten the potentiometer, but do not tighten the nut or setscrew.

5. Adjust the feedback potentiometer. Refer to ADJUSTMENTS. Tighten the nut and setscrew without moving the potentiometer body or shaft to avoid changing the setting. Connect the plug.

6. Close the motor compartment doors. Connect the battery.

Electronic Control Module Replacement 1. Disconnect the battery connector and open the motor compartment door.

2. Disconnect the wire harness plugs to the Electronic Control Module.

3. Prevent the Electronic Control Module from falling while removing the mounting capscrews, washers and nuts.

4. Use caution when handling the Electronic Control Module to avoid spreading the heat-transfer grease from the underside of the module to the surrounding areas.

5. Install heat-transfer grease on the underside of the replacement module and the frame. Install the module on the frame panel using the four capscrews, washers and nuts.

6. Connect the wire harness plugs.

7. Refer to ADJUSTMENTS to adjust the potentiometers on the circuit board for proper operation.

8. Check the position of the dipswitches to be sure the switches are set correctly. Refer to DI PSWITCHES.

Sheet 6: Steering System Steer Motor Assembly and Steering Chain Replacement 1. Disconnect the battery and open the motor compartment doors.

2. Disconnect the wire harness plug to the feedback potentiometer. Remove the nuts that fasten the feedback potentiometer bracket to the frame.

3. Hold the motor assembly and remove the capscrews, nuts and washers that fasten the motor assembly to the frame panel.

4. Carefully tip the top of the assembly away from the panel to remove the motor and feedback potentiometer bracket out of the truck. Do NOT bend the bracket. Remove the steering chain from the sprocket and remove the motor assembly.

5. Remove the steering chain from the master drive unit sprocket as required by pulling the chain anchor pins out of the holes in the sprocket. Clean and lubricate the chain using multi-purpose grease.

6. Make sure the master drive unit is aligned for straight travel. Install the steering chain on the master drive unit sprocket. Install the pin of the chain anchor in the first hole before the axle centerline.

7. Install the new motor, sprocket, and feedback potentiometer assembly. Tighten the capscrews and nuts to 31 N-m (23 Ib \ ft) torque.

8. Adjust the feedback potentiometer. Refer to ADJUSTMENTS.

TYPICAL OPERATING VOLTAGES The following table lists typical operating voltages for a correctly adjusted steering system. Measured voltages should be within 10% of the values listed in the table. Voltages are measured between the designated test point and TP3 (ground). See Figure 6-8.

Figure 6-7 -Typical Operating Voltages

Sheet 6: Steering System

Figure 6-8 -Test Point and Connector Reference TROUBLESHOOTING

Sheet 7: Steering System--Wire Guidance II STEERING SYSTEM - WIRE GUIDANCE II INTRODUCTION GENERAL This section has the description, adjustments, repair and troubleshooting for the optional WIRE GUIDANCE system.

This system electrically controls a motor to turn the Master Drive Unit (MDU) for steering.

See Section 6 STEERING SYSTEM for trucks equipped with the standard EPS STEERING SYSTEM (trucks without wire guidance).

Trucks equipped with wire guidance have a means of automatically controlling the steering system and a means of manually controlling the steering system. Refer to OPERATION MODES. The system of automatically steering the lift truck is referred to as "wire guidance" or "guidance" in this section. The system of manually steering the lift truck is referred to as "manual steering" in this section.

NOTE: This lift truck can be operated with the operator facing the steer tire or the operator facing the load forks.

Throughout this manual the terms right, left, front and rear relate to the viewpoint of an operator standing in the truck facing the steer tire. See Figure 7-2.

NOTE: All mechanical parts of the steering must be in good condition and correctly adjusted for correct guidance operation.

NOTE: The load wheels MUST BE THE SAME SIZE, in good condition and the bearings must be lubricated and correctly adjusted for correct guidance operation.

DESCRIPTION The wire guidance system is a system to automatically steer the lift truck. The system senses a magnetic field from an electric signal carried by a guide wire buried in the floor. A wire driver generates the signal carried by the guide wire. The wire driver is part of the location installation and operates on AC power.

The lift truck has the following guidance parts: sensors at each end of the lift truck, an Electronic Control Module (ECM), gearmotor, tach generator, tach steer module, Master Drive Unit (MDU) potentiometer, guidance light, guidance switch, guidance alarm, and steering indicator gauge. The guidance light, switch, alarm and steering indicator gauge are located on the instrument panel for operator control of the system. See Figure 7-1.

There are two sensors. One sensor is at each end of the lift truck. When the lift truck is following the guide wire, each sensor is directly over the guide wire. The sensors sense the signal from the guide wire and send signals to the ECM. The ECM controls the gearmotor rotation, which turns the MDU for steering. The MDU potentiometer sends MDU position information to the ECM. The slow down and automatic shutoff feature of the ECM will decrease the lift truck speed or stop the lift truck if the guidance system cannot sense the signal from the guide wire. The shutoff circuit will also stop the lift truck if certain steering components malfunction. The guidance switch at the instrument panel provides operator control of the guidance system. A light near the guidance switch and an alarm indicate guidance system operation. A steering indicator gauge shows the position of the steer tire. A tach generator, gear driven by the steering wheel and a tach steer module provides the steering input signal to the ECM when the lift truck is in manual steering.

Figure 7-1 -Wire Guidance

Sheet 7: Steering System--Wire Guidance II 1. STEERING WHEEL 2. TACH STEER MODULE 3. TACH GENERATOR 4. MULTIPLE CONDUCTOR CABLE 5. GUIDANCE SWITCH 6. GUIDANCE LIGHT 7. ALARM 8. TRACTION CIRCUIT 9. ECM 10. BATTERY 11. STEERING GEARMOTOR 12. MDU POTENTIOMETER 13. MDU AND CHAIN 14. SENSOR (STEER TIRE) 15. SENSOR (LOAD WHEEL) Each sensor is fastened to a bracket located near the floor. The steer tire sensor bracket is on the frame at the drive unit end of the lift truck. The bracket for the load wheel sensor is between the load wheels. The ECM is located in the motor compartment above the gearmotor. The alarm, switch, light and steering indicator gauge are fastened on the instrument panel. There are control cables that provide the electrical connections between the operators compartment and the drive unit compartment.

OPERATION MODES Lift trucks equipped with the optional wire guidance system steering control are also capable of manual steering.

Manual steering is available when the wire guidance switch is in the "OFF" position. The operator uses a steering wheel mounted in the operator compartment to control the steering when the truck is in the manual steering mode.

Wire Guidance NOTE: The guidance system must have a signal from the wire driver of the correct amplitude and frequency. The standard frequency is 6,240 to 6,260 Hz with a wire current of 76 to 80 ma. The frequency and the wire current can each be different for each installation. Make sure the frequency and wire current from the wire driver is correct for the sensors on the lift truck. See the labels on the sensors. The Yale wire driver has the frequency and wire current on a label inside the door. See the manufacturer for other wire drivers.

NOTE: A lift truck equipped with "wire guidance" has 1 FRONT SENSOR ASSEMBLY and 1 REAR SENSOR ASSEMBLY Each SENSOR ASSEMBLY supplies 2 signals a RIGHT SIGNAL and a LEFT SIGNAL. A total of 4 SIGNALS are sent by the 2 SENSORS ASSEMBLIES during "wire guidance" operation. The ECM uses the SIGNALS to monitor lift truck position in relation to the GUIDE WIRE and to automatically steer the lift truck. See Figure 7-2.

The wire guidance system controls the electric power steering system to steer the lift truck along the guide wire. The operator activates the guidance system by pushing the guidance switch to the ON position. The guidance system can be activated or deactivated at anytime, by pushing the switch ON or OFF. The operator must steer the lift truck close enough to the wire and at the correct angle for the system to sense the signal. See Figure 7-2. If the lift truck is in a position so that the system senses the signal and the guidance system has been activated, the system will automatically find the guide wire.

Manual steering is possible when the guidance system is first activated if the system cannot sense a signal. The alarm and flashing light will both operate during this condition. Steering will become automatic when the system is activated and the sensors can sense a signal. The alarm will stop operating and the flashing light will be continuously illuminated after the lift truck is following the guide wire. The alarm and flashing light will again operate if the guide wire signal is lost. The system will then slow the lift truck in two stages to try to sense the signal again. If the guide wire signal cannot be sensed, the system will deenergize the traction circuit and apply the brake.

Sheet 7: Steering System--Wire Guidance II

Figure 7-2 -Operation of the Guidance System 1.

2.

3.

4.

GUIDE WIRE LOAD WHEEL GUIDANCE SENSOR STEER TIRE

When the wire guidance switch is ON and the lift truck is following the guide wire, the steering is controlled by the steer tire sensor signals and load wheel sensor signals. The left and right signals from each sensor are near equal when a sensor is centered over the guide wire. If a sensor is not centered over the guide wire, then the signal from the portion of the sensor which is closest to the guide wire is stronger than the signal from the opposite side of the sensor. The left and right sensor signals become unequal or unbalanced as the center of the sensor moves away from the guide wire. During normal guidance operation, the centerline of the lift truck is centered over the guide wire.

The wire guidance system receives signals from the system sensors and from the MDU potentiometer. The ECM uses the input signals to keep the lift truck following the path of the wire.

The wire guidance system is deactivated and the operator must manually steer the lift truck when the guidance switch is in the OFF position.

Manual Steering When the wire guidance switch is OFF the steering is controlled by the operator rotating the steering wheel. The steering wheel is located in the operator compartment and is connected to a tach generator. The output from the tach generator goes to the tach steer module. The tach steer module sends a signal to the ECM to move the MDU. See Section 6 -STEERING SYSTEM for additional information on how manual steering works. Refer to INTRODUCTION, DESCRIPTION.

HOW TO OPERATE THE WIRE GUIDANCE SYSTEM The operation of the wire guidance system is controlled by the guidance switch. Pushing the switch to the ON position, as the lift truck comes to the guide wire, energizes the guidance system to find the wire. This is the "search mode" of guidance. The guidance light is a flashing light, the alarm makes a noise and the lift truck is automatically limited to "slow speed".

For the system to find the guide wire, the lift truck must be driven at a slow speed to the guide wire. The guidance system can find the guide wire at an angle of 30° or less when traveling in the steer tire direction. When traveling in the load wheel direction, it is necessary to align the lift truck on the guide wire. The lift truck must be aligned within approximately 44 mm (1.75 in) of the guide wire. See Figure 7-2. Both sensors are used when traveling in the load wheel direction. Only the steer tire sensor is used when traveling in the steer tire direction.

When the guidance system first senses the magnetic signal from the guide wire, it automatically steers the lift truck to follow the wire. This is the "acquisition mode". The manual steering will not operate. If the guidance system finds the guide wire, the guidance light will not be a flashing light, but will remain ON. The alarm stops making a noise.

This is the "automatic mode".

If the lift truck is moving too fast or is at too sharp an angle, the guidance system cannot align the lift truck on the guide wire. If this happens, the alarm continues to make noise and the light continues to be a flashing light. The system will return to the "search mode" and it will be necessary to again manually steer the lift truck toward the guide wire.

As the guidance system finds the guide wire, the alarm continues to make noise and the light continues to be a

Sheet 7: Steering System--Wire Guidance II flashing light. The guidance system automatically steers the lift truck to align it over the guide wire ("acquisition mode "). The automatic shut-off circuit is not activated and manual steering will not operate. The automatic shut-off circuit is activated after the lift truck is aligned and the alarm stops making noise. This is the "automatic mode". At this time, the light will not be a flashing light, but will remain ON. If the guidance system finds the guide wire but later loses the signal from the wire, the light is a flashing light and the alarm makes noise. These conditions occur when the center of the lift truck is approximately 32 mm (1.25 in) off the guide wire. If this happens, the system will first slow the lift truck to a maximum speed of approximately 6.4 km/h (4 mph). If the system still cannot find the signal, it will then slow the lift truck to a maximum speed of approximately 3.6 km/h (2.25 mph). These conditions occur when the center of the lift truck is approximately 38 mm (1 .5 in) off the guide wire. If the system cannot find the wire to return to the "automatic mode", automatic shut-off occurs. These conditions occur when the center of the lift truck is approximately 44 mm (1.75 in) off the guide wire. The traction circuit is deenergized and the brake is applied.

If automatic shut-off occurs, it is necessary to reset the system. Turn the key switch to the OFF position, then energize the electrical system of the lift truck for continued operation.

When a direction change is made in guidance, the light is a flashing light and the alarm comes on for approximately 1-3 seconds. During this time the automatic shut-off function is deactivated. This permits the lift truck to make the necessary steering corrections and then automatically steer the lift truck in the opposite direction. The guidance system will also adjust for steer tire sensor or steer tire and load wheel sensor operation depending on the direction the lift truck is now traveling.

NOTE: If the guidance switch is in the ON position when the key is turned to the ON position, the guidance system will automatically operate on guidance. The lift truck will operate on guidance until the guidance switch is pushed to the OFF position for manual steering or until automatic shut-off occurs. There will NOT be automatic steering unless the lift truck is on the guide wire.

CHECKS AND ADJUSTMENTS GENERAL WARNING: Disconnect the battery by separating the connector before opening the compartment cover or inspecting / repairing the electrical system. If a tool causes a short-circuit, the high current flow from the battery can cause an injury or parts damage.

WARNING: The capacitor in the SCR controller can hold an electrical charge after the battery is disconnected.

To prevent electrical shock and injury, discharge the capacitor before inspecting or repairing any component in the rear compartment. Wear safety glasses. Make certain the battery has been disconnected. Use a screwdriver or jumper wire between the two terminals to discharge capacitor C1.

Table 7-2 shows the functions of the different components of the ECM. Figure 7-4 shows the location of these components. Table 7-1 shows the function and the normal voltage for the different ECM terminals. Table 7-3 shows display code descriptions.

NOTE: Do not do any adjustments if the system operates correctly.

WARNING: Do not operate a lift truck that needs adjustment or repairs. Report the need for adjustment or repairs immediately. If adjustment or repair is necessary, put a "DO NOT OPERATE" tag in the operator's area.

Remove the key from the key switch.

NOTE: If a check or an adjustment takes longer than 10 seconds, it can be necessary to move the steering wheel slightly. The ECM will remove power from the steering gearmotor if there are no steering changes in a 10 second period. Some checks or adjustments require power to the gearmotor.

NOTE: The checks, adjustments and test procedures in this section are for testing and adjusting the separate components. The procedures are not in a specific sequence and this sequence is NOT a troubleshooting sequence.

WARNING: Many of the checks and adjustments are done with the battery connected. Never have any metal on your fingers, arms or neck. During some checks or adjustments, the operator must move the lift truck. The person doing the adjustments must make the adjustments with the system energized. Make sure the operator does not move the lift truck to cause an injury.

CAUTION: The steering chain MUST be correctly adjusted for the guidance system to operate correctly AND to make the checks and adjustments correctly. Check and if necessary, adjust the steering chain. Refer to ADJUSTING THE STEERING CHAIN CLEARANCE.

Sheet 7: Steering System--Wire Guidance II To read the displays on the ECM circuit board or do the manual checks, you must have access to the ECM. For access, open the motor compartment doors and remove the ECM cover. See Figure 7-3.

Figure 7-3 -ECM and Logic Board 1.

2.

3.

4.

5.

ECM COVER NUTS AND WASHERS LOGIC BOARD SET ELECTRICAL PLUGS SPACERS AND WASHERS

The wire guidance system uses the ECM test circuit to check for correct operation and adjustment of each part of the system. The test circuit automatically makes some checks during operation. Other checks can be done manually. These last checks are usually necessary as part of the adjustment procedures and are found in MANUAL CHECKS and in ADJUSTMENTS of this section. Switch S1 on the ECM circuit board, is used to change the manual check mode. Push the Mode button to change between checks. The two displays on the ECM circuit board indicate the results of the checks. See Figure 7-3 and Table 7-1 for the locations and functions of the parts of the circuit board. The ECM check circuit has 13 manual checks 01 through 11, 13 and 14.

To do some of the tests correctly, the center of the sensors must be directly over the guide wire. The guidance system must have a signal from the wire driver of the correct amplitude and frequency. The standard frequency is 6,240 to 6,260 Hz with a wire current of 76 to 80 ma. The frequency and the wire current can each be different for each installation. Make sure the frequency and wire current from the wire driver is correct for the sensors on the lift truck. See the labels on the sensors. The Yale wire driver has the frequency and wire current on a label inside the door. See the manufacturer for other wire drivers. The manual tests must be done on a straight section of the guide wire. For other checks the steer tire must be set for straight travel. Do not move the steering after the steer tire has been set until told to do so in the procedure.

Figure 7-4 -ECM Logic Board 1. ECM CIRCUIT BOARD 2. LEFT DISPLAY 3. MODE BUTTON 4. RIGHT DISPLAY 5. UP AND DOWN BUTTONS 6. LED 1 7. STEER BALANCE ADJUSTMENT RT 1 8. LED 2 9. MDU POTENTIOMETER ADJUST RT 2 10. STEER SENSOR ADJUST RT 4 11. LOAD SENSOR ADJUST RT 5

Sheet 7: Steering System--Wire Guidance II 12. SWITCHES 1 AND 2 13. MEDIUM SPEED ADJUST RT 6 14. SLOW SPEED ADJUST RT 7 15. TEST POINTS TP1 -TP15 Table 7-1 -Guidance ECM Component Functions

Table 7-2 -Guidance ECM Terminals

CHECKS GENERAL CAUTION: The steering chain MUST be correctly adjusted for the guidance system to operate correctly AND to make the checks and adjustments correctly. Check and if necessary, adjust the steering chain. Refer to ADJUSTMENTS, ADJUSTING THE STEERING CHAIN CLEARANCE.

Checking for Short-Circuits to the Frame It is important for the correct operation of the guidance system that all system components have electrical insulation.

There must be electrical insulation between the frame of the lift truck and each component. If a connector, cable, wire or component is making a connection to the frame, a malfunction can occur. The position of a motor cable can make a magnetic field that can change the sensor signal. Electrical static can also cause a malfunction. Make sure all cables are installed in the same position if they were moved for checking or replacement. Make sure all shields are correctly installed and connected. Make sure all insulation and isolators are correctly installed. Repair all short-circuits as soon as they are found. Keep the battery and battery compartment clean and painted. Keep all carbon dust and dirt removed from the inside of all the motors. Use dry compressed air.

CHECKS TO THE LIFT TRUCK

Sheet 7: Steering System--Wire Guidance II 1. Move the lift truck away from the guide wire. The area should also be away from any electrical or magnetic fields. Connect the negative lead from a digital voltmeter (FLUKE MODEL 8060A MULTIMETER or equivalent) to TP15 on ECM board. Put the positive lead on terminals TP8, TP9, TP10 and TP11. Turn the key switch on. Operate the truck in the forward and reverse directions. The highest reading should be 1 volt. If the reading at any of the terminals is over 1 volt, there is a wire connection to the frame, probably in the traction circuit. See Figure 7-4 for TP locations.

2. Do the same tests with the voltmeter as in Step 1. Operate the hydraulic system and then the STEERING SYSTEM. If the reading at any of the test points is over 1 volt, there is a wire connection to the frame, probably in the hydraulic or steering circuits.

3. Move the lift truck to an area that does NOT have a guide wire. Turn the steering wheel for a full right or left turn.

Activate the guidance system. Accelerate the lift truck with the steering handle or steering wheel still positioned for a full right or left turn. If the guidance system attempts to steer the lift truck out of the turn, there is a traction circuit connection to the frame. The connection makes the guidance system operate as if it were on an energized guide wire. This operating condition is usually from a high resistance connection. A dirty battery or motor can cause this condition.

4. To check for wire connections to the frame, disconnect the battery so that the connector is completely free and use an ohmmeter to check the circuits. Check for 50,000 ohms or more between each terminal of the part of the battery connector on the lift truck and a clean connection on the frame. Make sure there are no electrical connections to the frame of the lift truck. Wires or terminals without insulation can cause these connections.

Isolators for circuit boards that are missing, broken or not installed correctly can also cause these connections.

5. Check for voltage between each terminal of the connector on the battery and a clean metal connection on the frame of the lift truck. It is normal to measure some voltage between the battery and the frame even if the resistance checks are correct. If a voltage is measured, use an ammeter to determine if the current level is acceptable. Current in excess of 100 milliamperes can cause a problem.

There can be a voltage on the frame if the battery is dirty or if the battery has a defect. Clean the battery and battery compartment as necessary. There can also be a voltage on the frame if there is carbon dust in the motors. Use dry compressed air to remove the carbon dust from all motors.

AUTOMATIC CHECKS The following paragraphs have a description of the automatic checks that are done by the test circuit of the ECM. See Table 7-3. There is also a description of the numbers on both of the ECM displays during normal operation.

LEDs 1 and 2 will flash for any of the displays shown in Table 7-3.

The logic system of the ECM makes internal checks for correct operation. The checks are automatic and occur during manual or automatic steering.

NOTE: When the lift truck is aligned on an energized guide wire with the guidance system activated, the guidance system will automatically steer the lift truck.

If the center of the lift truck moves off the guide wire by approximately 32 mm (1.25 in), the guidance system will show a display of "5d 01 ". LEDs 1 and 2 will flash. The guidance system will limit the lift truck to a maximum travel speed of "medium speed".

The maximum "medium speed" is: OS030EB.....................................6.1 + \ - 0.5 km/hr (3.8 + \ - 0.3 mph) If the center of the lift truck moves off the guide wire by approximately 38 mm (1 .5 in), the guidance system will show a display of "5d 02". LEDs 1 and 2 will flash and the guidance system will limit the lift truck to a maximum travel speed of "slow speed".

Table 7-3 -Display Code Descriptions

Sheet 7: Steering System--Wire Guidance II

The maximum "slow speed" is 3.8 + \ - 0.5 km/hr (2.25 + \ _ 0.3 mph).

If the center of the lift truck moves off the guide wire by approximately 44 mm (1.75 in), the guidance system will show a display of "A5 11 ". LEDs 1 and 2 will flash and automatic shut-off occurs. The traction system is disabled and the brake is applied. All of the other "Stop Conditions" shown in Table 7-3 will either prevent lift truck movement in the guidance mode or stop the lift truck as just described.

A display of "dd 05" indicates that there is a fault in the "manual" circuit of the guidance switch. A display of "dd 06" shows that both forward and reverse directions have been simultaneously selected. The lift truck will not operate. A display of "dd 07" indicates an internal fault. The lift truck can be operational. Replacement of the logic board is required when "dd 07" is displayed. The "Watchdog" check is an automatic check that checks for faults that can reset the ECM during automatic steering. The "dd 40" display indicates a "Watchdog" fault has occurred to indicate a possible problem as a guide to the service person. These faults usually occur only once. The lift truck is operational, but there could be a problem. This display can be caused by a poor connection that is a good connection most of the time.

A display of "A5 00" shows that the operator platform is above the height where travel is permitted. The traction circuit is disabled. Lowering the platform below the limit will enable the traction circuit.

A display of "A5 01 "shows that the MDU potentiometer signal is out of the correct range. This fault can be caused by the following: (1) a poor connection to any of the potentiometer wires, (2) incorrect adjustment, (3) a defective potentiometer or (4) the MDU turned beyond the normal range.

A display of "A5 02" shows that there is no change in the signal from the MDU potentiometer when there should be.

This fault can be caused by a defective steering gearmotor, a mechanically jammed MDU or a defect in the MDU potentiometer or circuit.

A display of "A5 03" shows that the signal from the MDU potentiometer is the reverse of the correct signal.

This fault is caused by reversed leads to either the MDU potentiometer or steering gearmotor.

A display of "A5 04" shows that the steer signal from the tach generator is out of the correct range. This fault can be caused by the following: a. A poor connection at the tach generator or tach steer module. b. Incorrect adjustment. c.

A defective tach generator or tach steer module.

A display of "A5 05" shows that the signal from the guidance switch is out of the correct range during the "acquire" or "automatic" mode. This fault can be caused by a poor connection of the switch wires.

A display of "A5 06" shows that both the forward and reverse directions have been selected when the guidance switch is in the "automatic" mode. This fault is caused by a fault in the direction control switches, switch wiring or switch adjustments.

A display of "A5 10" shows that one of the four sensor signals is below the normal range during operation. This fault can be caused by a poor connection or a defective sensor.

Sheet 7: Steering System--Wire Guidance II A display of "A5 11 "shows that the lift truck is off the guide wire as previously described.

A display of "A5 12" shows that the left-to-right signal ratio of the sensors is out of the correct range. This fault can be caused by a poor connection or a defective sensor.

A display of "A5 13" shows that the average left/right signal from a sensor set has dropped below the necessary level for correct guidance operation. This fault can be caused by a defective sensor or a weak signal from the guide wire.

A display of "A5 14" shows that one of the four sensor signals is missing. This fault can be caused by an open connection or a defective sensor.

A display of "A5 30" shows that there is an error in the program memory of the Erasable Programmable Read Only Memory (EPROM) chip. This fault can be caused by a defective EPROM or other logic device.

A display of "A5 31" shows that there is an error in the Electrically Erasable Programmable Read Only Memory (EEPROM) chip. This fault can be caused by a defective EEPROM or other logic device.

WARNING: An error code "A5 31" can also be caused by turning the power off while switch S1 is in the "open" (down) position. Then, energizing the system when switch S1 is in the "closed" (up) position. Turn the power off for at least five seconds and then turn the power back on. If the error code still exists, the logic board must be replaced.

A display of "dd dd" shows that switch S1 on the logic card is in the "open" (down) position for the check functions.

Switch S1 is set to the "closed" (up) position for normal operation.

A display of "dd 05" shows that the signal from the guidance switch is out of the correct range during the "manual" mode. This fault can be caused by a poor connection of switch wires.

A display of "dd 06" shows that both forward and reverse signals are present at the same time. This fault is normally caused by a malfunctioning forward or reverse switch.

A display of "dd 07" shows an internal fault. Replace the logic board.

A display of "dd 40" shows that Watchdog reset has occurred as described earlier.

MANUAL CHECKS There are manual checks 01 through 11,13 and 14. Access the manual checks by setting switch S1 on the logic board to the "open" (down) or manual position. See Figure 7-4. The lift truck electrical system must be energized to make the checks. I n the manual mode the display will show "dd dd". The two digits on the left display indicate the step number. The two digits on the right display indicate the variable value being read or adjusted.

There are no decimal points, so when reading voltages, 4.1 volts will be indicated as "41" on the right display. Press the Mode button to advance to the next check. You must advance through the steps in numerical order to get to the check you want. Traction or steering power is not enabled in some checks. Setting switch S1 to the "closed" (up) position at any time will return the system to normal operation.

Check 01 -Operator Controls This check checks the operation of the operator guidance controls. Push the Mode button on the logic board so that the left display shows "01 ". The alarm will make a noise and the guidance indicator will flash. The right display will show "22" (2.2 volts) or less when the guidance button is in the Manual position. The right display will show "27" to "40" (2.7 to 4.O volts) when the guidance button is in the Automatic position. If any of these voltages are not correct, there is a fault in the guidance switch or associated wiring. Steering and traction operations are disabled during this check.

Check 02 -Steering Input Voltage The amplified voltage from the steering input is shown on the right display during this check. Push the Mode button on the logic board so that the left display shows "02".

The right display will show "24"to "26" with the steering wheel stationary. The right display will show a value less than "24" to greater than "01 " (< 2.4 to > 0.1 volts) while the steering wheel is being continuously rotated CW. The right display will show a value greater than "26" to less than "49" (> 2.6 to < 4.9 volts) while the steering wheel is being continuously rotated CCW. Voltages below 0.1 volts or above 4.9 volts will cause shut-off. Steering and traction operations are disabled during this check.

Check 03 -MDU Potentiometer Coarse Amplifier The amplified voltage from the MDU potentiometer is shown on the right display during this check. Push the Mode

Sheet 7: Steering System--Wire Guidance II button on the logic board so that the left display shows "03". The right display will show "25" (2.5 volts) with the steer tire positioned for straight travel. The right display value decreases as the steer tire is positioned further to the right.

The right display value increases as the steer tire is positioned further to the left. The right display will show between 01 and 03 (0.1 to 0.3 volts) at a full right turn. The right display will show between 47 and 49 (4.7 to 4.9 volts) at a full left turn. Voltages above 4.9 volts or below 0.1 volts will cause shut-off. Steering and traction operations are not disabled during this check.

Check 04 -MDU Centering This check checks the MDU centering. Push the Mode button on the logic board so that the left display shows "04".

The system will energize the steering motor to move the MDU to the position that the system considers "center" (steer tire positioned for straight travel). The right display will show "25" (2.5 volts) indicating the MDU is "centered".

The MDU can be adjusted to physical center (straight travel) by adjusting RT2.

Check 05 -Direction Inputs This check checks each direction signal and the zero speed (plugging) signal. Push the Mode button on the logic board so that the left display shows "05". The right display will show one of the displays as indicated in Table 7-4.

The left digit of the right display will show the presence or absence of the plugging signal. The right digit of the right display shows the direction status. The traction and STEERING SYSTEMS are both operational during this check.

Table 7-4 -Direction/Plugging Inputs

EXAMPLES: 1. The lift truck was driven load end first and plugged to a stop. The plugging signal was present (left digit"1 ") and the last direction selected (during plugging) was steered end first (right digit "1 "). The display therefore shows "11 ". If the lift truck had been allowed to accelerate after plugging to a stop, the plugging signal would have been dropped. The display would show "01 ".

2. The lift truck was driven load end first and coasted to a stop (no plugging). The right display will show "02".

Checks 06 Through 09 -Sensor Levels Checks 06 through 09 display the values from the sensor input voltages. See Figure 7-5. With the lift truck centered on the guide wire and with Check 10 -Steered End Sensor Balance and Check 11 - Load End Sensor Balance adjusted, checks 06 through 09 should show near equal values on the right-hand display. Steering and traction operations are disabled during these checks. See Table 7-4 for sensor details. See Table 7-1 for sensor values.

Push the Mode button on the logic board so that the left display shows "06". Check that Check 06 displays the value for the right side of the steered end sensor assembly (right front sensor signal).

Push the Mode button on the logic board so that the left display shows "07". Check that Check 07 displays the value for the left side of the steered end sensor assembly (left front sensor signal).

Push the Mode button on the logic board so that the left display shows "08". Check that Check 08 displays the value for the right side of the load end sensor assembly (right rear sensor signal).

Push the Mode button on the logic board so that the left display shows "09". Check that Check 09 displays the value for the left side of the load end sensor assembly (left rear sensor signal).

Figure 7-5 -Direction Orientation

Sheet 7: Steering System--Wire Guidance II

Check 10 -Steered End Sensor Balance This check checks the balance between the right and left signals of the steered end sensor. The lift truck MUST be in the position so that the SENSOR at the steered end is centered within 0.2 inch of the energized guide wire and the load end sensor is centered within 0.5 inch of the energized guide wire. Set switch S1 to the "closed" (up) position to allow manual lift truck operation. After the lift truck is centered, set switch S1 to the "open" (down) position and push the Mode button on the logic board so that the left display shows "10". If the right-hand display does not show "00", the sensor assembly is not balanced. The balance can be set by adjusting RT4 for a display of "00". Steering and traction operations are disabled during these checks.

Check 11 -Load End Sensor Balance This check checks the balance between the right and left signals of the load end sensor. The lift truck MUST be in the position so that the SENSOR at the load end is centered within 0.2 inch of the energized guide wire and the steered end sensor is centered within 0.5 inch of the energized guide wire. Set switch S1 to the "closed" (up) position to allow manual lift truck operation. After the lift truck is centered, set switch S1 to the "open" (down) position and push the Mode button on the logic board so that the left display shows " 11 ". If the right-hand display does not show "00", the sensor assembly is not balanced. The balance can be set by adjusting RT5 for a display of "00". Steering and traction operations are disabled during these checks.

Check 13 -Medium Travel Speed This check puts the lift truck in the medium travel speed mode to set the medium travel speed. RT6 is adjusted to set the medium travel speed. The traction and STEERING SYSTEMS are both operational during this check. Refer to ADJUSTMENTS, ADJUSTING THE TRAVEL SPEEDS for additional information.

Check 14 -Slow Travel Speed This check puts the lift truck in the slow travel speed mode to set the slow travel speed. RT7 is adjusted to set the slow travel speed. The traction and STEERING SYSTEMs are both operational during this check. Refer to ADJUSTMENTS, ADJUSTING THE TRAVEL SPEEDS for additional information.

NOTE: The EV-100 LX traction motor controller is also used to control travel speed and traction cutout at 5385 mm (212 in) and at 6909 mm (272 in). The EV-100 LX traction motor controller has different FUNCTION VALUE SETTINGS for different lift truck models, different mast heights and different travel options. See Section 3 -EV-100 LX MOTOR CONTROLLER, FUNCTION 13 (SPEED LIMIT 3) for additional information.

Checking the Operation of the Shutoff Circuit 1. Move the lift truck to a section of guide wire that has a straight section.

2. Energize the guidance system of the lift truck. Make sure the guide wire is correctly energized.

3. Align the centerline of the lift truck on the guide wire. Operate the lift truck along the straight section of the guide wire in the steer tire direction. Stop the lift truck and disconnect wire 5P2 from terminal 2 of the power terminal strip on the ECM. Install tape on the wire to prevent a short-circuit. See Figure 7-6.

4. Operate the lift truck at a slow speed on guidance in the steer tire direction.

5. Check that the lift truck slowly moves off the guide wire. If the lift truck moves off the guide wire by approximately 32 mm (1.25 in), the guidance system will show a display of "5d 01 ". LEDs 1 and 2 will flash and the guidance system will slow the lift truck to a maximum speed of approximately 6 km/h (4 mph). If the lift truck moves off the guide wire by approximately 38 mm (1 .5 in), the guidance system will show a display of "5d 02". LEDs 1 and 2 will flash and the guidance system will slow the lift truck to a maximum speed of approximately 4 km/h (2 mph).

Sheet 7: Steering System--Wire Guidance II If the lift truck moves off the guide wire by approximately 44 mm (1.75 in), the guidance system will show a display of "A5 11 ". LEDs 1 and 2 will flash and automatic shut-off occurs. The traction system is disabled and the brake is applied.

6. Reconnect wire 5P2 to terminal 2 of the power terminal strip on the ECM.

Checking the Steering at Mast Heights 1. Raise the operator compartment to a fork height of: 3810 mm (150 in) to 5385 mm (212 in) 3810 mm (150 in) to 6910 mm (272 in) 2. Set the steering for a right or left turn of more than 7°.

3. Check that the traction system (forward and reverse travel) is disabled on all lift trucks.

4. Set the steering for less than a 7°turn (straight travel).

5. Check that the traction system will operate and that the brake is released.

6. Raise the operator compartment to a fork height above: 5385 mm (212 in) 6910 mm (272 in) 7. Set the steering for less than a 7°turn (straight travel).

8. Check that the traction system (forward and reverse travel) will not operate.

NOTE: OS030EB model trucks with optional "TRAVEL ABOVE 5385 mm (212 in) WITH 7°RESTRICTED STEER TO MFH" will have traction above 5385 mm (212 in) fork height.

Figure 7-6 -Transistor Resistance Check Points 1.

2.

3.

4.

5.

6.

7.

TRANSISTOR BLOCK M1 TRANSISTOR BLOCK M2 POWER TERMINALS PLUG PIN SOCKETS C2/E1 E2 C1

Checking the ECM Power Transistors 1. Disconnect the battery so that the connector is completely free. Open the motor compartment door and remove the cover on the ECM. 2. Remove the electrical plug at the right side of the logic card.

3. Use a Fluke Model 8060A Multimeter. Set the multimeter to do the diode test as described in the Fluke instruction manual.

Sheet 7: Steering System--Wire Guidance II 4. Connect the meter to each of the locations shown in Table 7-5. Check for the resistance values listed. If any of the 12 readings for EACH transistor block (M1 AND M2) are not within the values shown, replace the transistor block that has the incorrect reading.

NOTE: The specifications values shown in Table 7-5 were taken using a Fluke Model 8060A Multimeter. Other meters and other transistor manufacturers will give different readings because of internal differences in the meters and transistors. When using other meters, compare the resistance values of the transistors being tested to the resistance values of a new transistor of the same manufacturer. Allow a 10% variation for correct readings. The readings must be within the values shown in Table 7-5.

Table 7-5 -Transistor Resistance Values

Checking the Steering Contactor The steering contactor is fastened to the Electrical Panel Assembly in the motor compartment.

NOTE: Before checking the steering contactor, verify that battery volts is present at wire 3P2. If battery volts is not present, check the steering contactor fuse (35 amp) and the power cables.

1. Disconnect the battery so that the connector is completely free and open the motor compartment doors.

2. Check that wires 10 and 13 are connected to the control terminals of the contactor. Check that cables 3P2 and 4P2 are connected to the power terminals. Check that all connections and wires are in good condition.

3. If all connections are good, remove the wires from the control terminals. Use an ohmmeter to check for continuity between the control terminals. If there is continuity, the contactor coil is good. If not, replace the contactor. See Section 3 - ELECTRICAL SYSTEM, CONTACTORS for additional information.

ADJUSTMENTS GENERAL CAUTION: The steering chain MUST be correctly adjusted for the guidance system to operate correctly AND to make the checks and adjustments correctly. Check and if necessary, adjust the steering chain. Refer to ADJUSTING THE STEERING CHAIN CLEARANCE. NOTE: Make sure the battery has a corrected specific gravity of at least 1.250. Do not make any adjustments if the system operates correctly.

WARNING: Do not operate a lift truck that needs adjustment or repairs. Report the need for adjustment or repairs immediately. If adjustment or repair is necessary, put a "DO NOT OPERATE" tag in the operator's area.

Remove the key from the key switch.

NOTE: The adjustment procedures in this section are for adjusting the separate components. The procedures are not in a specific sequence and this sequence is NOT a troubleshooting sequence.

WARNING: Many of the adjustments are done with the battery connected. Never have any metal on your fingers, arms or neck. During some adjustments, the operator must move the truck. The person doing the adjustments must make the adjustments with the system energized. Make sure the operator does not move the

Sheet 7: Steering System--Wire Guidance II truck to cause an injury.

Some of the following adjustments are done using the ECM check circuit. For access to the ECM circuit board, open the motor compartment doors and remove the cover from the ECM. See Figure 7-3.

ADJUSTING RT1 TO THE OPERATIONAL MIDPOINT This procedure adjusts the ECM to the steer signal input from the tach steer module. See Figure 7-4 for the location of RT1.

CAUTION: Do not move the steering wheel unless told to while performing this adjustment procedure.

1. Set switch S1 on the ECM circuit board to the "open" (down) position. With the key switch ON, the displays will show "dd dd".

2. Push the Mode button on the ECM for a left display of "02".

3. Adjust RT1 for a right-hand display of "25".

4. Check that the right-hand display changes to less than "25" with the steer wheel being continuously rotated for a right turn.

Figure 7-7 -Steering Handle Assembly 1.

2.

3.

4.

5.

6.

7.

8.

STEERING WHEEL TACH STEER ASSEMBLY TACH STEER BRACKET SPACER TIMING BELT STEERING SHAFT STEERING KNOB ASSEMBLY SPROCKET

5. Check the right-hand display changes to greater than "25" with the steer wheel being continuously rotated for a left turn.

6. If any of the readings are not correct, check the tach generator, tach steer module and wiring for normal signals to the ECM. See Figure 7-7.

7. Return switch S1 to the "closed" (up) position for normal operation.

8. Adjust the RT1 potentiometer to its operational midpoint. a. Turn the RT1 potentiometer clockwise until the steer motor starts to pulse (initial turn on). Make note of the position of the screwdriver slot on the RT1 potentiometer.

Mark one side of the screwdriver slot and the face of the RT1 potentiometer if necessary. b. Turn the RT1 potentiometer counterclockwise, counting the number of times the RT1 potentiometer is turned, until the steer motor again starts to pulse (initial turn on). Make note of the number of revolutions the RT1 potentiometer was turned from Step (a.) to Step (b.).

Sheet 7: Steering System--Wire Guidance II c.

Divide the value calculated in Step (b.) by 2. Record this value.

d. Adjust RT1 to its operational midpoint by turning the rt1 potentiometer clockwise from the Step (b.) position, a number of turns equal to the value calculated in Step (c.).

Figure 7-8 -Adjusting the Steering Chain Clearance 1.

2.

3.

4.

5.

6.

REDUCER SPROCKET STEERING CHAIN MDU SPROCKET ADJUSTING NUT ADJUSTING BOLT RIGID MATERIAL

ADJUSTING THE STEERING CHAIN CLEARANCE 1. Disconnect the battery so that the connector is completely free and open the motor compartment doors.

2. Operate the steering to find the point where the steering chain has the least deflection. Rotate the steer wheel to the right (CW) to turn the MDU to the full right turn (CW) position. Slowly rotate the steer wheel to the left (CCW) to turn the MDU to the left (CCW) position and watch the steering chain. The point of least deflection is the point where the steering chain is straight or nearly straight between the sprockets.

3. Install a thin piece of rigid material on the chain between the sprockets. The material must have a straight edge.

Make sure the chain is tight on the opposite side of the sprockets. Measure the clearance between the bottom of the straightedge of the rigid material and the chain. See Figure 7-8. The middle of the chain must have a clearance of 1.3 to 3.3 mm (0.05 to 0.13 in).

4. Tighten the adjustment nut at the MDU sprocket for a maximum clearance of 1.3 to 3.3 mm (0.05 to 0.13 in) between the chain and straight edge. Do NOT tighten the adjusting nut for a clearance of less than 1.3 mm (0.05 in).

5. Close and fasten the motor compartment doors.

CENTERING THE STEER TIRE 1. Move the lift truck to a safe level area. Turn the key switch off and remove the key.

WARNING: Disconnect the battery by separating the connector before opening the compartment cover or inspecting/repairing the electrical system. If a tool causes a short-circuit, the high current flow from the battery can cause an injury or parts damage.

2. Disconnect the battery and separate the connectors.

3. Open drive unit compartment doors.

Sheet 7: Steering System--Wire Guidance II 4. Verify that the steer chain is properly adjusted. Refer to ADJUSTING THE STEERING CHAIN CLEARANCE. 5. Do not move the steering wheel. Do not use the steering wheel to position the steer tire for straight travel. Use a large screwdriver at the armature shaft of the steering gearmotor to move the steer tire to the straight travel position.

The steer tire is set for straight travel when the distance from the front edge of the steer tire wheel to the frame plate is equal to the distance from the rear edge of the steer tire wheel to the frame plate.

6. The MDU potentiometer must now be centered. Do not reconnect the battery at this time. Refer to CENTERING THE MDU POTENTIOMETER to complete this procedure.

CENTERING THE MDU POTENTIOMETER This procedure adjusts the ECM to the MDU pot signal. See Figure 7-11 for the location of MDU potentiometer.

NOTE: This procedure is ONLY NECESSARY after the MDU potentiometer has been replaced, or if the MDU potentiometer adjustment has been disturbed. The potentiometer must be positioned at mid-range with the steer tire positioned for straight travel.

Adjustment can be checked and the mid-range position of the potentiometer can be verified by checking for 2.3 to 2.7 volts at the pot wiper (wire 17) with the steer tire positioned for straight travel and the system energized. Use TP15 for the negative test point. Refer to ADJUSTMENTS, CENTERING THE STEER TIRE for the procedure to center the steer tire.

Proceed to ADJUSTING RT2 FOR STRAIGHT TRAVEL if the potentiometer DOES NOT need adjustment.

Perform the following Steps (1.) to (10.) if the potentiometer DOES require adjustment.

1. Verify that the steer chain is properly adjusted. Refer to ADJUSTING THE STEERING CHAIN CLEARANCE. 2. Position the steer tire for straight travel. Refer to ADJUSTMENTS, CENTERING THE STEER TIRE. 3. Disconnect the electrical plug for the MDU potentiometer. Loosen the nut (5) that fastens the potentiometer to the bracket (4).

4. Adjust the MDU potentiometer for mid-range. Compare the resistance measured between wires 16 and 17 with the resistance measured between wires 17 and 18. The potentiometer is at the mid-range position when the resistance readings are equal within 50 ohms. Rotate the potentiometer body for the correct resistance readings.

5. Tighten the nut that fastens the potentiometer to the bracket without moving the potentiometer body. Maintain the clearance between the bottom of the coupling and the gearmotor housing. See Figure 7-11. Reconnect the electrical plug for the MDU potentiometer.

6. Reconnect the battery and energize the electrical system of the lift truck.

7. Set switch S1 on the ECM circuit board to the "open" (down) position. With the key switch ON, the displays will show "dd dd".

8. Push the Mode button on the ECM for a left display of "03".

9. Use RT2 to adjust the right-hand display to "25" with the steer tire set for straight travel. This will set RT2 to approximately the mid-range position. Return switch S1 to the "closed" (up) position for normal operation.

10. Adjust RT2 for straight travel. Refer to ADJUSTING RT2 FOR STRAIGHT TRAVEI. The board will be used Hyster or Yale, small or large chassis, Guidance or non-W/G, 24V or 36V, and Traction performance or standard. The board receives the prox switch inputs, as well as a steering input, and outputs signals necessary to invoke speed limits or inhibit traction.

Steering input: Steering input for wire guided trucks is the feedback pot wiper, into a high-impedance comparator input into the TRAM. This can be adjusted for +/-10°, using two pots on the TRAM. Proximity inputs: The proximity switches on a standard truck are at 24", 60",150", and 212"/272" heights, and the Traction

Sheet 7: Steering System--Wire Guidance II Performance option has an additional 120" proximity.

There is an input pin to the TRAM which is wired high (in the truck's harness) to indicate when Traction Performance option (120" proximity) is present.

Faults: Since the proximity switches will turn off sequentially (all switches use the same target), the TRAM can monitor for "unacceptable" input patterns. If an unacceptable pattern for - 0.4 seconds, the TRAM will fault. Depending on the fault input pattern, the TRAM will either inhibit travel or be in "limp home" mode, allowing 1.2 mph. If a fault occurs long enough to latch, then the fault input condition must be corrected and the keyswitch recycled to clear the fault. If the truck is in a fault state which inhibits travel, the truck can usually move into a "limp-home" mode by lowering the platform to the next proximity switch level.

Speed limits, large chassis: The TRAM uses the three speed limits of the GE EV100LX card, selectively pulling PA4, PA5, or PA6 down to ground.

Speed limits, small chassis: The throttle wires pass through the TRAM, normally through a 5k adjustment pot (for 1.2 mph). A FET can be actuated to shunt around the pot (full speed), and another FET can switch another pot in parallel to the first, effectively achieving 2.2 mph.

Traction Enable/Inhibit: The board receives the traction enable (and brake disengaging) signal from the steering controller. This passes through a high current FET on the TRAM, then supplies the high side of the forward/reverse contactors (GE controller) or the traction enable line (Curtis PMC controller).

Indicators: There are 3 status LED's: A green LED indicates that power is on, and the TRAM is functioning.

A yellow LED to indicate when steering is within 10°of center. This indicator will work with either Atlas binary input or the TRAM's internal comparator.

A red LED to indicate a latched fault status.

There are five LED's corresponding to the 5 proximity switch inputs. These will be lighted if the corresponding proximity switch input is present. If a fault condition occurs, the technician can easily check these indicators to verify proximity switch function.

TRAM ADJUSTMENTS TRAM Steer Adjustment Verification 1. Set steer tire straight ahead.

2. Check that Yellow LED on TRAM is on. If it is off, proceed to "TRAM Steer Adjustment" below.

3. Turn steer tire to 4° Left, as measured between the steer tire edge and the front "bumper" of the frame. For RTC trucks, this may be accomplished by turning the steering input knob, then inserting a spacer block between the handle return spring and its stop rod.

4. Check that Yellow LED is still ON. If it is OFF, proceed to "TRAM Steer Adjustment" below.

5. Turn steer tire to 10°Left. Check that Yellow LED is off. If it is on, proceed to "TRAM Steer Adjustment" below.

6. Turn steer tire to 4°Right.

7. Check that Yellow LED is on. If it is off, proceed to "TRAM Steer Adjustment" below.

8. Turn steer tire to 10° Right. Check that Yellow LED is off, adjustment is not necessary. If it is on, proceed to "TRAM Steer Adjustment" below.

TRAM Steer Adjustment 1. Start with steer tire pointed straight ahead. If yellow LED is off, adjust TRAM Pot RV1 counterclockwise until LED turns on. If you reach the end of travel for RV1 (clicking noise) and LED is still off, turn RV2 counterclockwise

Sheet 7: Steering System--Wire Guidance II until LED turns on.

2. Turn steer tire 10°Left (see step 3 above). If LED is off, turn RV2 counterclockwise until LED turns on.

3. Turn RV2 clockwise until LED turns off, then turn 1 additional turn clockwise.

4. Turn steer tire 10°Right. If LED is off, turn RV1 counterclockwise until LED turns on.

5. Turn RV1 clockwise until LED turns off, then turn 1 additional turn clockwise.

ADJUSTING RT2 FOR STRAIGHT TRAVEL This procedure adjusts the ECM to the MDU signal for lift truck straight travel. See Figure 7-4 for the location of RT2.

CAUTION: Make sure the steering input signal is balanced and the MDU potentiometer is centered according to the previous procedures. Refer to ADJUSTING RT1 TO THE OPERATIONAL MIDPOINT and CENTERING THE MDU POTENTIOMETER. CAUTION: Make sure the steering wheel is not moved while performing this adjustment procedure.

NOTE: Before starting this procedure, find a section of floor that is smooth and level for approximately 30.5 m (100 ft). Install a pointer at the center of the rear (load wheel end) of the lift truck.

1. Turn the key switch on. Set switch S1 on the ECM circuit board to the "open" (down) position. Push the Mode button on the ECM for a left display of "04". The system will energize the steering motor to move the MDU to the position that the system considers "center". The right display will show "25" (2.5 volts) indicating the MDU is "centered". To check and adjust the MDU to the physical center (straight travel), do Step 2.

2. Have the operator drive the lift truck in the reverse direction (load wheel end first). Adjust potentiometer RT2 for straight travel as described in sub Steps (a.) through (d.). Clockwise adjustment of RT2 makes the lift truck turn to the left. Counterclockwise adjustment makes the lift truck turn to the right. See Figure 7-5 for left and right orientation. Potentiometer RT2 is correctly adjusted when the lift truck will travel in a straight line within 152 mm (6 in) in 9.1 m (30 ft). To check that the lift truck is moving in a straight line, do the following procedure: NOTE: The ECM will remove power from the steering gearmotor if there are no steering changes within a 10 second period. If sub Steps (a.) through (d) take longer than 10 seconds, it will be necessary to cycle the keyswitch off and then on to supply power to the gearmotor and re-select mode 4 before adjusting RT2. See Step 1. a. Make a mark on the floor under the point of the pointer. b. Have the operator drive the lift truck in the reverse direction for 4.6 m (15 ft). Make a mark on the floor under the point of the pointer. c.

Have the operator drive the lift truck in the reverse direction for another 4.6 m (15 ft). Make another mark on the floor under the point of the pointer.

d. Draw a straight line between the first and last marks. The center mark must be within 76 mm (3 in) of the line. If the center mark is within this specification, RT2 is correctly adjusted. If the mark is NOT within the specification, adjust RT2 as described in this procedure until the mark is within the specifications.

NOTE: If the lift truck cannot be adjusted for straight travel after performing Steps (a.) through (d.), the MDU potentiometer may be out of range. Adjust the MDU potentiometer to mid-range. Refer to CENTERING THE MDU POTENTIOMETER. 3. After the MDU is set for straight travel (Step 2), push the Mode button for a left-hand display of "03". The right-hand display should show "25" (2.5 volts) with the MDU positioned for straight travel.

4. Check for the correct range of operation by rotating the steering wheel for a full right turn and then a full left turn.

The right display value should decrease as the MDU turns to the right. The right display will show between 01 and 03 at a full right turn. The right display value should increase as the MDU turns to the left. The right display will show between 47 and 49 at a full left turn. The MDU will move 85 to 95°in each direction from the center position.

5. Set switch S1 on the circuit board to the "closed" (up) position for normal operation.

ADJUSTING THE TRAVEL SPEEDS

Sheet 7: Steering System--Wire Guidance II NOTE: The EV-100 LX traction motor controller is also used to control travel speed above 3810 mm (150 in) and traction cutout at 5385 mm (212 in) and at 6909 mm (272 in). The EV-100 LX traction motor controller has different FUNCTION VALUE SETTINGS for different lift truck models, different mast heights and different travel options. See Section 3 -EV-100 LX MOTOR CONTROLLER, FUNCTION 11 (SPEED LIMIT 1) and FUNCTION 13 (SPEED LIMIT 3) for additional information.

WARNING: Travel speed affects stability. Do Not adjust MEDIUM SPEED or SLOW SPEED beyond specifications.

Medium Speed NOTE: The medium travel speed adjustment RT6 is located on the ECM. The "medium speed" is adjusted to 6.1 t 0.5 km/hr (3.8 t 0.3 mph) NOTE: The numbers in the"( )" of the following procedure are the item numbers in Figure 7-9.

1. Make sure the battery has a corrected specific gravity of at least 1.250. Make sure that the lift truck has been operated at full speed for approximately 10 minutes before checking the speed.

2. Find a section of floor that is smooth and level for approximately 30.5 m (100 ft).

3. Set switch S1 on the ECM circuit board to the "open" (down) position. Push the Mode button for a left-hand display of"13". This will set the control card to adjust the maximum "medium travel speed" for the lift truck.

Figure 7-9 -Checking Lift Truck Travel Speeds 1.

2.

3.

4.

5.

6.

7.

8.

BEGIN ACCELERATION ACCELERATION AREA STARTTIMING LINE TIMED DISTANCE RT7 ('%) M (33 FT.) LINE (%) TIMED DISTANCE RT6(*) M (56 FT.) LINE(*) STOPPING AREA

4. Move the lift truck to the beginning of the approximate 30.5 m (100 ft) distance (1). Put a line on the floor for the starting point (3). Put a line on the floor at the 17 m (56 ft) (7) distance. Draw the lines in the center of the 30.5 m (100 ft) distance. The area at each end is for acceleration and a distance to stop the lift truck.

5. Have personnel at the start line and at the 17 m (56 ft) line (7) to check the times.

Operate the lift truck at full speed and check the total time it takes for the lift truck to travel the distance. The lift truck must travel at full speed for the total time of the distance.

6. If the time is less than 10 seconds the "medium" travel potentiometer RT6 is set for a speed faster than the specified speed. The potentiometer must be adjusted CCW. If the time is more than 10 seconds the potentiometer must be adjusted CW for a faster travel speed. Adjust the potentiometer in small amounts and repeat Steps 4, 5 and 6 until the speed is correct.

Slow Speed NOTE: The numbers in the"( )" of the following procedure are the item numbers in Figure 7-9.

NOTE: The slow travel speed adjustment RT7 is located on the ECM. The "slow speed" for all lift trucks is adjusted to 3.8 +/- 0.5 km/hr (2.25 t 0.3 mph).

Sheet 7: Steering System--Wire Guidance II 1. Make sure the battery has a corrected specific gravity of at least 1.250. Make sure that the lift truck has been operated at full speed for approximately 10 minutes before checking the speed.

2. Find a section of floor that is smooth and level for approximately 30.5 m (100 ft).

3. Set switch S1 on the ECM circuit board to the "open" (down) position. Push the Mode button for a left-hand display of "14". This will set the maximum "slow travel speed" for the lift truck. The correct maximum travel speed for the "slow speed" is 3.8 plus or minus 0.5 km/hr (2.25 plus or minus 0.3 mph).

4. Move the lift truck to the beginning of the approximate 30.5 m (100ft) distance (1). Put lines on the floor for the starting point (3) and 10 m (33 ft) (5) distances in the center of the 30.5 m (100 ft) distance. The area at each end is for acceleration and a distance to stop the lift truck.

5. Have other personnel at the start line (3) and the 10 m (33 ft) line (5) to check the times. Operate the lift truck at full speed and check the total time it takes for the lift truck to travel the 10 m (33 ft) distance (4). The lift truck must travel at full speed for the total time of the 10 m (33 ft) distance.

6. If the time is less than 10 seconds, the "slow" travel potentiometer RT7 is set for a speed faster than the specified speed. The potentiometer must be adjusted CCW. If the time is more than 10 seconds the potentiometer must be adjusted clockwise for a faster travel speed. Adjust the potentiometer in small amounts and repeat Steps 4, 5 and 6 until the speed is correct.

ADJUSTING SENSORS TO LIFT TRUCK CENTERLINE CAUTION: Make sure that all of the previous adjustment procedures have been completed correctly. The following adjustments will NOT be correct if the previous adjustments are not correct. THE FOLLOWING ADJUSTMENTS MUST BE DONE IN THE SEQUENCE LISTED. CAUTION: Use a section of guide wire at least 30.5 m (100 ft) long. This section must be straight within 3.2 mm (0.125 in) in 3.05 m (10 ft). The guide wire frequency and current must match the sensors. The standard frequency and current is 6.250 kHz at 78 ma.

7. Measure the lift truck width to locate the centerline at each sensor location. Install vertical pointers at the centerline. Nylon tie wraps work well for the pointers. The points of the pointers must just clear the floor and be visible during travel.

8. If necessary, adjust each sensor so that the center of the sensor is on the centerline and has a floor clearance of 65.09 to 68.26 mm (2.5625 to 2.6875 in).

9. Move the lift truck so that both pointers are centered over the guide wire. The steered end sensor must be centered within 2.5 mm (0.1 in) of the guide wire. The load end sensor must be centered within 76 mm (3 in) of the guide wire.

NOTE: Verify steered end sensor adjustment by measuring the voltage between the green and white wires of the sensor. Adjust the sensor left to right and look for the voltage closest to "0". The truck and guide wire must be energized and sensor plugs "C" and "D" must be connected. See Figure 7-10.

Figure 7-10 -Adjusting Sensors to Centerline 10. Set switch S1 on the ECM circuit board to the "open" (down) position. Push the Mode button for a left-hand display of "10". Connect a digital voltmeter between test points TP1 0 and TP1 1. Adjust RT4 on the circuit board for a voltage reading of "0.00" between TP10 and TP1 1.

11. If necessary, move the lift truck so that the load end pointer is centered over the guide wire. The load end sensor

Sheet 7: Steering System--Wire Guidance II must be centered within 2.5 mm (0.1 in) of the guide wire. The steered end sensor must be centered within 76 mm (3 in) of the guide wire.

NOTE: Verify load end sensor adjustment by measuring the voltage between the green and white wires of the sensor. Adjust the sensor left to right and look for the voltage closest to "0". The truck and guide wire must be energized and sensor plugs "C" and "D" must be connected. See Figure 7-10.

12. Push the Mode button for a left-hand display of "11 ". Connect a digital voltmeter between test points TP8 and TP9. Adjust RT5 on the circuit board for a voltage reading of "0.00" between TP8 and TP9.

13. Set switch S1 to the "closed" (up) position to return the lift truck to normal operation.

14. Push the guidance button on the instrument panel to the ON position for guidance operation. Operate the lift truck 9.1 metres (30 ft) in the direction of the MDU. Coast to a stop. Do not plug or use the brake to stop the truck. Check that the steered end pointer stays within 13 mm (0.5 in) of the guide wire. Check that the load end pointer is approximately the same distance from the guide wire and on the same side as the steered end pointer.

If the load end sensor is not following in the correct position, the steered end pointer AND sensor must be moved. Move the steered end pointer and sensor so that they are on the same side and are the same distance from the guide wire. Make sure to maintain the correct floor clearance (Step 2) and keep the centers of the sensor and pointer on the same centerline. Repeat this step until the pointers track correctly.

NOTE: If the pointers are 5 mm (0.2 in) or more to one side of the guide wire, recheck the sensor balance adjustment (Step 10.). Also recheck the MDU potentiometer RT2 adjustment. Refer to ADJUSTING RT2 FOR STRAIGHT TRAVEL. 15. Operate the lift truck 9.1 m (30 ft) in the direction of the load wheels. Coast to a stop. Do not plug or use the brake to stop the truck. Check that the load end pointer stays within 13 mm (0.5 in) of the guide wire. If the pointers are 5 mm (0.2 in) or more to one side of the guidewire, the steered end pointer AND sensor must be moved. Measure the distance that the load end pointer is off the guide wire. Move the steered end pointer and sensor that same distance towards the opposite side of the guide wire.

EXAMPLE: If the load end pointer is 13 mm (0.5 in) to the right side of the guide wire, move the steered end sensor and pointer toward the left side of the guide wire. The steered end sensor and pointer are moved from the original position to the left 13 mm (0.5 in).

16. Do Steps 8 and 9 until both pointers stay on the guide wire without any adjustment.

REPAIR WARNING: Disconnect the battery by separating the connector before opening the compartment cover or inspecting/repairing the electrical system. If a tool causes a short-circuit, the high current flow from the battery can cause an injury or parts damage.

WARNING: The capacitor in the SCR controller can hold an electrical charge after the battery is disconnected.

To prevent electrical shock and injury, discharge the capacitor before inspecting or repairing any component in the rear compartment. Wear safety glasses. Make certain the battery has been disconnected. Use a screwdriver or jumper wire between the two terminals to discharge capacitor C1.

WARNING: Do not operate a lift truck that needs adjustment or repairs. Report the need for adjustment or repairs immediately. If adjustment or repair is necessary, put a "DO NOT OPERATE" tag in the operator's area.

Remove the key from the key switch.

General There are repair procedures for the following parts: the steering wheel assembly, the sensors at each end of the unit, the Electronic Control Module (ECM) assembly, and the gearmotor unit. There are also repair procedures for the guidance components at the instrument panel.

See Section 4 -DRIVE UNIT for removal and repair procedures for the MDU.

STEERING GEARMOTOR Replacing the Gearmotor Assembly and Steering Chain

Sheet 7: Steering System--Wire Guidance II NOTE: Item numbers in ( ) are the item numbers shown in Figure 7-11.

1. Set the steering for straight travel. Refer to ADJUSTMENTS, CENTERING THE STEER TIRE. 2. Disconnect the battery connector. Open the drive unit compartment doors. Disconnect the flasher-light. Remove the drive unit compartment cover.

3. Disconnect the electrical plug for the MDU potentiometer (3). Remove the nuts and bolts that fasten the MDU potentiometer bracket (4) to the frame plate (2).

4. Hold the gearmotor assembly (1) and remove the capscrews, nuts and washers that fasten the gearmotor assembly to the frame plate.

5. Carefully tip the top of the assembly away from the plate to rotate the MDU potentiometer bracket away from the frame. Do NOT bend the bracket. Remove the steering chain (5) from the sprocket and remove the gearmotor assembly.

6. See Figure 7-12 to repair the gear box of the gearmotor assembly. Clean and lubricate the gears and bearings using Yale multi-purpose grease P/N 1500318-02.

7. If necessary, remove the steering chain from the MDU sprocket (6) by pulling the chain anchor (7) pins out of the holes in the sprocket.

8. If the steering chain was removed, clean and lubricate the chain using Yale multi-purpose grease P/N 1500318-02.

9. Make sure the steer tire is positioned for straight travel. Refer to ADJUSTMENTS, CENTERING THE STEER TIRE. If removed, install the steering chain on the MDU sprocket. Install the pin of the chain anchor in the first hole before the axle centerline (8) as shown in Figure 7-11.

10. Make sure the setscrew (6) for the MDU potentiometer is aligned as shown in Figure 7-11. Install the sprocket of the replacement gearmotor assembly in the steering chain.

Figure 7-11 -Steering Gearmotor and MDU Assembly 1.

2.

3.

4.

5.

6.

7.

8.

9.

GEARMOTOR ASSEMBLY FRAME PLATE MDU POTENTIOMETER POTENTIOMETER BRACKET STEERING CHAIN MDU SPROCKET CHAIN ANCHOR FIRST HOLE BEFORE CENTERLINE GEARMOTOR SETSCREW MUST BE AS SHOWN (FACING YOU WITH STEERING SET FOR STRAIGHT TRAVEL) 10. COUPLING 11. COUPLING SETSCREW CAUTION: If the gearmotor assembly has the MDU potentiometer installed, make sure to align the MDU bracket to the frame during installation. Do NOT bend the bracket.

Sheet 7: Steering System--Wire Guidance II 11. Hold the assembly and install the capscrews, washers and nuts that fasten the assembly to the frame panel.

Tighten the capscrews and nuts to 31 Nm (23 Ib \ ft) torque.

12. Adjust the steer chain. Refer to ADJUSTMENTS, ADJUSTING THE STEERING CHAIN CLEARANCE. 13. If the MDU potentiometer is not installed, install the potentiometer. Make sure to install the potentiometer so that there is a clearance as shown in Figure 7-11. Center the MDU potentiometer. Refer to ADJUSTMENTS, CENTERING THE MDU POTENTIOMETER. 14. Adjust RT2 for straight travel. Refer to ADJUSTMENTS, ADJUSTING RT2 FOR STRAIGHT TRAVEL. 15. Replace the drive unit compartment cover. Reconnect the flasher-light. Close and fasten the drive unit compartment doors. Reconnect the battery.

Figure 7-12 -Gear Box Assembly 1. MOTOR ADAPTER 2. GASKET 3. KEY 4. REDUCER HOUSING 5. WORM GEAR SET 6. BEARING CONE 7. BEARING CUP 8. LOAD RING 9. OIL SEAL 10. SHAFT 11. COVER 12. SNAP RING 13. COVER RING 14. SPACER 15. BALL BEARING 16. PLUG

Sheet 7: Steering System--Wire Guidance II Figure 7-13 -Steering Wheel Assembly 1. STEER KNOB ASSEMBLY 2. STEERING WHEEL 3. SHOULDER BOLT 4. SHAFT STEER 5. SPROCKET 6. TIMING BELT 7. LOCKNUT BEARING 8. LOCKWASHER-BEARING 9. BEARING CUP 10. BEARING CONE 11. TACH STEER BRACKET 12. SCREW 13. LOCKWASHER 14. TACH STEER ASSEMBLY 15. CAPSCREW 16. WASHER 17. WASHER 18. NUT 19. PLATE-TACH MOUNTING 20. SCREW 21. LOCKWASHER 22. FLAT WASHER 23. SPACER

STEERING WHEEL ASSEMBLY Removal and Disassembly NOTE: Complete disassembly is usually not necessary. Remove only the parts necessary to replace the defective part.

NOTE: The numbers in the"( )" of the following procedure are the item numbers in Figure 7-13.

1. Disconnect the battery connector.

2. Remove the console cover from the cowl.

3. Remove the steering knob assembly (1) from the steering wheel (2).

4. Remove the screw (3) and steering wheel (2) from the steering shaft (4).

5. Loosen the sprocket setscrews and remove two sprockets (5) and timing belt (6) from steering the assembly.

6. Remove the bearing locknut (7) and lockwasher (8) from the steering shaft (4).

7. Remove the steering shaft (4), two bearing cups (9) and bearing cones (10) from the steering bracket (11).

8. Tag and disconnect the wires to the tach steering assembly (14).

9. Remove the four capscrews (12), lockwashers (13) and the tach steering assembly (14) from the steering bracket (11).

10. Remove the two capscrews (15), washers (16), washers (17), nuts (18) and the tach mounting plate (19) from the steering bracket (11).

11. Remove the four capscrews (20), lockwashers (21), washers (22), spacers (23) and the steering bracket (11) from the support weldment.

Assembly and Installation NOTE: The numbers in the"( )" of the following procedure are the item numbers in Figure 7-13.

Sheet 7: Steering System--Wire Guidance II 1. Install the steering bracket (11) onto the support weldment with four capscrews (20), lockwashers (21), washers (22) and spacers (23).

2. Install the tach mounting plate (19) onto the steering bracket (11) with two capscrews (15), washers (16), washers (17) and nuts (18).

3. Install the tach steering assembly (14) onto the steering bracket (11) with four capscrews (12) and lockwashers (13).

4. Connect the wiring to the tach steering assembly (14).

NOTE: Reversing the tach generator wires will cause reverse steering.

WARNING: No steering or reverse steering can occur if the Tach Generator connections are not proper! The ECM CANNOT detect these faults and traction will be allowed.

5. Install the two bearing cups (9), cones (10) and the steering shaft (4) through the steering bracket (11).

6. Install the lockwashers (8) and bearing locknut (7) on to the steering shaft (4).

7. Install the two sprockets (5) and tighten the setscrews.

8. Install the timing belt (6).

9. Install the steering wheel (2) onto the steering shaft (4) with the screw (3).

10. Install the steering knob assembly (1) onto the steering wheel (2).

11. Install the console cover onto the cowl.

12. Connect the battery connector.

Figure 7-14 -Guidance Button, Indicators and Alarm 1.

2.

3.

4.

5.

6.

7.

8.

INSTRUMENT PANEL BATTERY INDICATOR/ HOURMETER STEERING INDICATOR BATTERY DISCONNECT SWITCH SLACK CHAIN WIRE GUIDANCE KEY SWITCH

REPLACE GUIDANCE SWITCH, INDICATOR, AND ALARM NOTE: Removal of each part is usually not necessary. Remove only the parts necessary to replace the defective part. The guidance switch and indicator are located in the instrument panel. The alarm is fastened to the front (upright side) of the operator platform.

Sheet 7: Steering System--Wire Guidance II NOTE: The numbers in the"( )" of the following procedure are the item numbers in Figure 7-14.

1. Disconnect the battery so that the connector is completely free.

2. Remove the screw that fasten steering wheel to the shaft of the steering mechanism. Remove the steering handle.

3. Remove the screws at the top of the instrument panel. Tilt the instrument panel to the open position for access to the parts.

4. To replace the switch or indicator, put tags on the wires for correct connection during installation. Pull the wire terminals off the switch or indicator terminals.

5. Push the switch assembly or indicator assembly out of the instrument panel. Push the replacement switch or indicator assembly into the instrument panel. Make sure the words on the switch are not upside down.

6. To replace the alarm, put tags on the alarm wires for correct connection during installation. Remove the bezel nut that fastens the alarm and remove the alarm. Install the replacement alarm and connect the wires as tagged during removal.

7. Close the instrument panel and tighten the screws. Install the steering handle on the shaft of the steering mechanism. Tighten the screw.

REPLACE THE MDU POTENTIOMETER 1. Set the steering for straight travel. Refer to ADJUSTMENTS, CENTERING THE STEER TIRE. 2. Disconnect the battery so that the connector is completely free.

3. Open the motor compartment door. Disconnect the electrical plug for the MDU potentiometer.

4. Loosen the setscrew that fastens the shaft of the potentiometer. See Figure 7-11. Loosen the upper coupling setscrew (11). Remove the nut that fastens the potentiometer to the bracket (4). Remove the potentiometer (3).

5. Center the MDU potentiometer. Refer to ADJUSTMENTS, CENTERING THE MDU POTENTIOMETER. 6. Adjust RT2 for straight travel. Refer to ADJUSTMENTS, ADJUSTING RT2 FOR STRAIGHT TRAVEL. 7. Close the motor compartment doors and connect the battery.

REPLACE THE ECM Replace the Complete Module NOTE: Complete disassembly is usually not necessary. Remove only the parts necessary to replace the defective part.

See Figure 7-15 and Figure 7-16.

1. Disconnect the battery so that the connector is completely free.

2. To replace the complete module, install tags on the wires at the terminal strip for correct connections during installation. Disconnect the wires from the terminal strip. Disconnect the plugs of the wiring cables.

3. Hold the module and remove the capscrews and washers that fasten the module to the frame plate. Access to the capscrews is from the traction motor compartment.

NOTE: Keep the frame area clean to prevent voids between the power base and the frame panel. Use a piece of plastic to cover the silicon grease on the power base or remove the grease.

4. Install silicon grease on the power base of the replacement module and the frame. Install the module on the frame panel using the four capscrews and the washers.

5. Install the wires on the terminal strip as marked during removal. Connect the wiring cable plugs.

6. Adjust the ECM. Refer to CHECKS AND ADJUSTMENTS, ADJUSTMENTS.

Sheet 7: Steering System--Wire Guidance II Replace the Logic Board Set NOTE: The logic board for the guidance ECM is actually a two-piece set. The set MUST be replaced as a single unit.

NOTE: The logic board does not normally get defects. The logic board can be damaged from a malfunction of the power base. If the power base has a defect, replace the complete module. If physical damage causes a defect in the logic board, replace the logic board set as described in the following procedure.

Figure 7-15 -ECM and Logic Board 1.

2.

3.

4.

5.

ECM COVER NUTS AND WASHERS LOGIC BOARD SET ELECTRICAL PLUGS SPACERS AND WASHERS

CAUTION: The electronic components can be damaged by electrostatic discharge. Use a special floor pad to help prevent an electrostatic charge. ALWAYS remove the electrostatic charge on your body before touching electronic components. Connect a static strap to your wrist and a good earth ground. Follow the directions on the package of the component.

NOTE: The numbers in the"( )" of the following procedure are the item numbers in Figure 7-15.

1. Disconnect the battery so that the connector is completely free.

2. Remove the nuts that fasten the cover (1) on the ECM. Install tags on all the electrical plugs (4) for correct connection during installation.

3. Disconnect the electrical plugs (4). The plugs are at the edges of the two circuit boards of the set (3).

4. Remove the spacers and washers (5) that fasten the logic board set (3). Remove the logic board set.

5. Install the replacement logic board set. Make sure the LEDs are at the top. Install the washers and spacers (5) to fasten the logic board set.

6. Install the electrical plugs (4) on the edges of the logic board set as marked during removal.

7. Adjust the ECM. Refer to CHECKS AND ADJUSTMENTS, ADJUSTMENTS. 8. Install the ECM cover (1) using the nuts and washers (2).

Replace the ECM Power Transistors NOTE: Make sure that the transistor block is defective before replacing the block. Refer to CHECKS AND ADJUSTMENTS, CHECKING THE ECM POWER TRANSISTORS. NOTE: The numbers in the"( )" of the following procedure are the item numbers in Figure 7-16.

1. Disconnect the battery so that the connector is completely free. Open the motor compartment doors.

2. Remove the nuts that fasten the cover on the ECM. 3. Disconnect the electrical plugs from each edge of the logic board set.

4. Remove the spacers and washers that fasten the logic board set. Remove the logic board set.

Sheet 7: Steering System--Wire Guidance II 5. Use a knife to carefully remove the protective coating on the terminals for the control leads of the transistor block (1) or (2) to be replaced.

6. Put tags on the control wires and power leads for correct connection during installation. Remove the power leads from the power terminals (3).

7. Use a soldering iron and pliers that have a long nose to remove the wires from the terminals of the transistor block. Use the pliers to pull each wire off each terminal as the soldering iron melts the solder. Do not hold the soldering iron on a terminal too long. The wire can get too hot and melt the insulation.

8. Remove the two screws and lockwashers (8) that fasten the block (1) or (2) to the heat sink plate. Remove the block.

9. Put a thin coating of silicon grease on the metal plate on the bottom of the replacement transistor block.

10. Install the replacement block (1) or (2) on the heat sink. Make sure the block is in the correct position to correctly connect the control wires. Tighten the screws (8).

11. Connect the control wires to the control terminals (9) of the transistor block as marked during removal. Use solder and a soldering iron to connect the wires to the terminals. Use pliers that have a long nose to hold the terminal under the connection to help keep heat out of the transistor. Do not hold the soldering iron on a terminal too long. The terminal can get too hot and damage the transistors or melt the wire insulation. Make sure to use enough heat to make a good solder joint.

12. Connect the power leads to the power terminal (3) as marked during removal.

13. Install the logic board set, plugs and ECM cover. Close the motor compartment doors.

Figure 7-16 -ECM Power Panel 1.

2.

3.

4.

5.

6.

7.

8.

9.

TRANSISTOR BLOCK M1 TRANSISTOR BLOCK M2 POWER TERMINALS PLUG PIN SOCKETS C2/E1 E2 C1 MOUNT SCREW AND WASHER CONTROL TERMINALS

REPLACE THE STEERING CONTACTOR NOTE: The steering contactor is fastened to the Electrical Panel Assembly in the motor compartment.

1. Disconnect the battery so that the connector is completely free and open the motor compartment doors.

2. Put tags on the steering contactor leads for correct connection during installation.

3. Remove the capscrews, nuts and washers that fasten the contactor to the Electrical Panel Assembly. Remove the contactor.

4. Install the replacement contactor in the same position as the old contactor. Reinstall the capscrews, nuts and washers that fasten the contactor to the Electrical Panel Assembly.

Sheet 7: Steering System--Wire Guidance II 5. Install the contactor leads as tagged during removal.

Figure 7-17 -Sensor Arrangement 1. LOAD WHEEL SENSOR 2. SENSOR BRACKET 3. SENSOR CABLE 4. TO ECM CONNECTOR 5. STEER WHEEL SENSOR 6. CAPSCREW 7. WASHER 8. NUT 9. FLOOR 10. KEY 11. PLUG "D" 12. PLUG "C"

REPLACE THE SENSORS NOTE: The replacement sensors must be for the frequency of the guide wire signal at the installation. See the decal on the sensor. The standard sensor frequency is 6,250 Hz. The Yale wire driver has the frequency and wire current on a label inside the door. See the manufacturer of other wire drivers for the installation frequency.

NOTE: Each sensor must have a cable of the correct length. New sensors have either a long (load wheel) or short (steer wheel) cable. Make sure to choose the sensor with the correct cable length during replacement.

CAUTION: The electronic components can be damaged by electrostatic discharge. Use a special floor pad to help prevent an electrostatic charge. ALWAYS remove the electrostatic charge on your body before touching electronic components. Connect a static strap to your wrist and a good earth ground. Follow the directions on the package of the component.

WARNING: To replace the load wheel sensor, the operator platform must be raised to provide access. The lowering of the operator platform or forks can cause an injury. Use blocks and chains on the mast and operator platform so that they cannot move. Make sure the moving parts are attached to a part that cannot move. See SAFETY PROCEDURES WHEN WORKING NEAR THE MAST, for specific instructions.

See Figure 7-17 and Figure 7-18.

1. Raise the operator platform for access to the load wheel sensor area between the load wheels. Use blocks and chains on the mast and operator platform so that they cannot move. Make sure the moving parts are attached to a part that cannot move. It can be necessary to remove the battery for access to the cable ties and wires from the load wheel sensor.

2. Disconnect the battery so that the connector is completely free and remove the cover for access to the electrical compartment. Discharge the INTERNAL CAPACITOR of the traction motor controller using the proper procedure.

CAUTION: The position of motor and other power cables can change the operation of the guidance system. DO NOT change the position of power cables during the replacement of sensors.

3. Remove all the cable ties and clamps that fasten the sensor cable. Make a note of the location of each cable tie

Sheet 7: Steering System--Wire Guidance II and position of the sensor cable for the installation.

4. Remove the cover on the ECM. Remove plug connector "C" for the load wheel sensor. Remove plug connector "D" for the steer wheel sensor. Fasten a string or small gauge wire to the connector plug. The string or wire must be longer then the length of the sensor cable. Carefully pull the cable toward the sensor. Remove the string or wire from the connector plug.

CAUTION: Check the orientation of the old sensor position for the replacement installation. The replacement sensor MUST be installed so that the same side of the sensor is toward the mount surface. The replacement sensor MUST ALSO have the cable toward the same side as the old sensor. The guidance system will NOT operate correctly if the sensor is not installed correctly.

5. Remove the two nuts, washers and capscrews that fasten the sensor. Remove the sensor.

6. Install the correct replacement sensor as shown in Figure 7-17. The cable for the load wheel sensor is longer than the cable for the steer wheel sensor. Make sure to install the correct sensor. If necessary, loosen the capscrews and nuts at the end of the sensor bracket to align the center mark on the sensor board. Fasten the sensor so that the floor clearance is 66.5 mm (2.63 in). If possible, the center mark on the sensor must align with the centerline of the lift truck. Tighten the sensor mount capscrews and nuts to 2.0 to 2.5 Nm (18 to 22 Ib \ ft in).

7. Fasten a string or wire used during removal to the connector plug of the replacement sensor. Carefully pull the string or wire to get the sensor cable to the ECM. Remove the string or wire. Install new cable ties at the same locations of the old cable ties. Install the cable clamp near the sensor.

8. Connect the sensor connector plug to the ECM. Connect connector plug "C" (load wheel sensor) to the "C" location. Connect connector plug "D" (steer wheel sensor) to the "D" location. See Figure 7-18. Connect the battery connector.

9. Adjust the ECM for the replacement sensor. Refer to ADJUSTMENTS, ADJUSTING SENSORS TO LIFT TRUCK CENTERLINE. 10. Remove the support or chain and lower the operator platform.

11. Install the ECM cover, close and fasten the electrical compartment door. Install the electrical compartment cover.

NOTE: Do not splice sensor leads. Splicing sensor leads can cause erratic guidance operation. Anytime a sensor lead is damaged, install a complete sensor assembly.

NOTE: When installing new sensors, install new terminal leads. Do not try to use the connector pins from the previous sensor assembly.

Figure 7-18 -Connector Plug Location 1.

2.

3.

4.

CONNECTOR PLUG "A" CONNECTOR PLUG "B" CONNECTOR PLUG "C" CONNECTOR PLUG "D"

TROUBLESHOOTING STEERING SYSTEM -WIRE GUIDANCE II

Sheet 7: Steering System--Wire Guidance II

Sheet 8: Hydraulic System HYDRAULIC SYSTEM INTRODUCTION This section describes the hydraulic system and contains the procedures for adjustment and repair. A guide for troubleshooting is included at the end of this section. Repair procedures for the mast and hydraulic cylinders are contained in Section 8. Section 2 contains the maintenance intervals for servicing the hydraulic oil and hydraulic filter.

DESCRIPTION The Hydraulic System includes the following major components: • • • • • • • •

Lift Pump and Motor Assembly Electro-Hydraulic Control Valve Accumulator Flow Regulator Filter Tank Main Lift Cylinder (2) Velocity Fuses (2)

Lift Pump and Motor The lift pump and motor assembly is located in the drive unit compartment. The motor that drives the lift pump will be a 24 volt or 36 volt motor depending on the truck battery voltage.

The lift pump only operates when the control handle is moved to select the lift function.

Mast Lift and Lower

Figure 8-1 -Control Handle Operation Rocker switches in the control handle allow the forks to be lifted or lowered. The OS030EB model has two switches, one for lift and the other for lower. The switches will automatically return to the neutral position when released

Manual Lowering The Manual Lowering Valve, located in the drive motor compartment is manually operated to lower the operator's plat form. Turn the manual lowering knob clockwise to open the valve. Turn the knob counterclockwise to close the valve. See NO TAG. WARNING: Make sure manual lowering valve is completely closed before lift truck operation. Unintentional mast lowering may occur if the valve is not closed.

WARNING: Before using the manual lowering feature, make sure there are no obstructions which would prevent the platform or forks from lowering.

Sheet 8: Hydraulic System Accumulator WARNING: The accumulator is pressurized. Never attempt to disassemble it or change the precharge. Personal injury can result.

A piston type accumulator is installed in the lift circuit to cushion the starting and stopping of the operator compartment. The accumulator is precharged with dry nitrogen to 2.07 MPa (300 psi). Maximum working pressure of the accumulator is 20.68 MPa (3000 psi). The accumulator is mounted to the manifold block. See Figure 8-2.

1. ACCUMULATOR 2. FLOW REGULATOR 3. MANIFOLD BLOCK Figure 8-2 -Flow Regulator and Accumulator Oil enters the accumulator when hydraulic system pressure is greater than accumulator pressure. As the hydraulic oil enters the accumulator, the nitrogen gas in the accumulator is compressed. Accumulator pressure rises until it is equal to hydraulic system pressure. When accumulator pressure is equal to hydraulic system pressure, no oil transfer occurs. Oil exits the accumulator into the hydraulic system when system pressure is less than accumulator pressure. The transfer of oil in and out of the accumulator during the increases and decreases of hydraulic system pressure reduces abrupt pressure changes in the hydraulic system and provides a cushioning effect to the operator's compartment and load.

Service parts are not available for the accumulator. If the accu-mulator is malfunctioning, it must be replaced as a assembly.

Flow Regulator A cartridge type flow regulator is incorporated in the mast man-ifold block to control lowering speed. See Figure 8-2.

The flow regulator allows full flow in one direction and controls flow in the opposite direction. The flow of hydraulic oil to the mast is unre-stricted and maximum lift speed is allowed. The flow of fluid from the mast back to the tank is controlled and lowering speed is regulated.

Sheet 8: Hydraulic System

Figure 8-3 -Hydraulic Schematic 1. FILTER 2. RELIEF VALVE 3. SOLENOID VALVE 4. PUMP MOTOR 5. PUMP 6. CHECK VALVE 7. FLOW REGULATOR 8. ACCUMULATOR 9. LOWERING CONTROL VALVE 10. LIFT CYLINDER The flow regulator cartridge is not a serviceable item. It must be replaced if it malfunctions. The flow regulator cartridge is marked with an arrow which indicates direction of free flow. See Figure 8-2. When replacing the flow regulator cartridge, be cer-tain that the arrow points toward the mast cylinders.

Flow regulators are supplied indifferent flow ratings depending on the mast. If replacement is necessary, be sure to install the correct part number.

The hydraulic filter is located inside the hydraulic oil tank. It is mounted on the bottom of the return line and incorporates an integral relief valve.

Table 8-1 -Hydraulic Filter Specifications

Tank A molded plastic tank is used as the hydraulic reservoir. Open the drive unit compartment and remove the drive unit

Sheet 8: Hydraulic System cover to access the hydraulic tank.

The molded outlet of the tank is located at the bottom. The top of the tank has an access plate bolted to it. There is a breather/fill-er and the tank inlet on the top of the access cover. Unscrew the breather/filler to expose the fill spout and strainer.

Figure 8-4 -Hydraulic Tank and Filter Assembly 1.

2.

3.

4.

5.

TANK FILTER BREATHER/FILLER OUTLET RETURN LINE

The breather, strainer and filter should be serviced in accor-dance with the recommended lubrication charts found is Sec-tion 2.

A sight glass is provided on the side of the tank to check fluid level. Be sure the operator platform is completely lowered when checking the hydraulic oil level.

Table 8-2 -Hydraulic System Capacities

Main Lift Cylinders The main lift cylinders are used to elevate the mast. See Sec-tion 8 -MAST for additional information.

Velocity Fuses The main lift cylinders are each equipped with a velocity fuse. The velocity fuses are designed to prevent uncontrolled lower-ing of the mast in the event of a hydraulic hose or line failure. If such a failure would occur the

Sheet 8: Hydraulic System velocity fuse would act as a flow regulator to allow the mast to lower at a controlled rate.

Figure 8-5 -Velocity Fuse WARNING: Never operate a mast with the velocity fuse disassembled or removed.

Velocity fuses are supplied in different flow ratings depending on the mast. If replacement is necessary, be sure to install the correct part number.

SPECIFICATIONS LIFT PUMP AND MOTOR Rated Flow (24V) Rated Flow (36V) Rated Maximum Pressure Operating Speed

32 litre/min (8.5 gpm)@ 2000 RPM 28 litre/min (7.4 gpm)@ 2000 RPM 21 MPa (3046 psi) 50 to 3500 RPM

Figure 8-6 -Lift Pump and Motor

Sheet 8: Hydraulic System 1.

2.

3.

4.

LIFT PUMP MOTOR LIFT PUMP PUMP INLET (SUCTION) PUMP OUTPUT (PRESSURE)

REPAIRS LIFT PUMP AND MOTOR Seals that are worn or damaged are the most common cause of pump repair. The pump bearings, gears and shafts also wear. Most service persons do not repair a pump that is worn. The cost of repairs can be greater than the cost of a new pump. The special back-up rings, seals and bushings in the hydraulic pump are replaceable. These parts come in the repair kit. The end covers also can be replaced. Replace the pump if other pump parts are damaged.

Removal WARNING: Disconnect the battery by separating the connector before opening the compartment cover or inspecting / repairing the electrical system. If a tool causes a short circuit, the high current flow from the battery can cause an injury or parts damage.

NOTE: If the motor must be removed, do all the steps of this procedure. To remove the pump, do Steps 1, 2, 6, and 7.

1. Disconnect the battery and open the front compartment doors. If the motor must be removed, put labels on the power cables and disconnect the power cables at the motor.

2. Position a drain pan under the lift pump. Loosen the hose clamp at the inlet and the hose fitting at the outlet of the pump. Oil can flow from the hoses when the hoses are disconnected. Have plugs ready to install in the hoses. Disconnect a hose and quickly install a plug in the hose. Disconnect the other hose us-ing the same procedure. If the motor must be removed, install plugs on the fittings at the pump to prevent dirt from entering the pump.

WARNING: The lift pump and motor is heavy. Be sure that all lifting devices (hoists, cables, chains, slings, etc.) are suitable and of adequate capacity to lift the lift pump and motor. The lift pump and motor can weigh approximately 253.6 kg (115 Ib).

3. Remove the M8 capscrews, washers, and spacers that fasten the bottom of the motor to the bracket.

4. Make a mark on the top of the motor housing for correct alignment of the motor during installation. Hold the motor as-sembly to keep it from falling and remove the other M8 capscrews, washers, and spacers that fasten the motor.

5. Use a sling around the pump motor and a crane to lift the motor and the pump. The crane and sling must have a lifting ca-pacity of approximately 45 kg (100 Ib). Do not damage the mo-tor terminals or pump fittings.

6. Remove the hydraulic fittings from the pump. Remove the two capscrews and lockwashers that fasten the pump to the motor. Slowly remove the pump from the motor.

NOTE: The recommended maintenance and repairs of the lift pump motor is covered in Section 3.

Seal Replacement WARNING: Be careful when removing or installing snap rings. These snap rings can come loose during removal or installation with enough force to cause an injury. Always use the correct snap ring pliers and wear eye and face protection during removal and installation.

CAUTION: If the pump is held in a vise for disassembly, use soft jaws in the vise. Make sure the vise does not hold the pump too tightly and cause distortion of the pump housing.

NOTE: Make notes of the locations of the parts and seals during disassembly. There are two types of special back-up rings. Make a note of the location of each type. See Figure 8-7.

1. Carefully remove the end covers. Make a note of the spe-cial back-up ring and seal arrangement. Do not disassemble the gear and bushing assembly.

Sheet 8: Hydraulic System 2. Carefully remove the bushing seals from the bushings and pump housing.

3. Inspect the pump gear assembly and the pump housing for wear and damage. Replace a damaged or worn hydraulic pump.

NOTE: Some pump housings will show gear marks. These marks are caused by the small clearances between the parts. Gear marks do not indicate a worn or damaged pump unless the pump does not operate according to the specifications.

4. If necessary, clean the internal parts of the hydraulic pump. Lubricate the parts with clean hydraulic oil as the pump is as-sembled.

5. Install the gear and bushing assembly in the pump hous-ing. Make sure each bushing is correctly aligned.

6. Install new bushing seals and special back-up rings. Install new housing seals. The correct arrangement is shown in Figure 8-7. Install the end covers and the special washers and capscrews. Tighten the capscrews to 46 Nm (34 Ibf ft).

7. Install a new oil seal on the shaft. Carefully press the oil seal into the end housing. Install a new snap ring.

Figure 8-7 -Lift Pump Disassembled 1. SCREW 2. BEADED TUBE 3. PRESSURE PLATE SEAL 4. SEAL 5. PRESSURE PLATE 6. SLEEVE BEARING 7. GEAR 8. SHEAR PIN 9. WASHER 10. RETAINING RING 11. BEARING 12. SPACER 13. OIL SEAL 14. RETAINING RING 15. DRIVE SHAFT 16. IDLER SHAFT ASSEMBLY Installation WARNING: The lift pump and motor is heavy. Be sure that all lifting devices (hoists, cables, chains, slings, etc.) are suitable and of adequate capacity to lift the lift pump and motor. The lift pump and motor can weigh approximately 253.6 kg (115 Ib).

1. Carefully install the lift pump on the motor with the four capscrews. Tighten the capscrews to 20 Nm (15 Ib \. ft.).

2. If the motor was removed, use the capscrews, washers, and spacers to install the pump and motor on the

Sheet 8: Hydraulic System brackets. Re-place damaged bushings. See the mount detail in Figure 8-8. Align the lift pump and motor with the mounting holes in the frame using a lifting device.

3. Clean the fittings and install them on the pump. The pump must have oil for first operation. Before connecting the hydrau-lic hoses, fill the pump with clean oil at the outlet fitting.

4. If necessary, clean the hydraulic hoses. Connect the hoses to the inlet and the outlet fittings on the pump.

5. Connect the power cables to the motor terminals accord-ing to the labels.

6. Check the hydraulic fluid level and connect the battery.

7. Operate the lift truck through all functions. Check for oil leaks. Check the hydraulic tank for the correct oil level.

Figure 8-8 -Lower Pump Mount 1.

2.

3.

4.

5.

PUMP MOTOR BRACKET BUSHING SPACER CAPSCREW AND WASHER

HYDRAULIC TANK Removal WARNING: Disconnect the battery by separating the connector before opening the compartment cover or inspecting / repairing the electrical system. If a tool causes a short circuit, the high current flow from the battery can cause an injury or parts damage.

1. Turn the key switch to the OFF position. Disconnect the battery.

2. Open the drive unit compartment and remove the drive unit cover.

3. Position a suitable drain pan in the drive unit compartment. See Table 8-2 for hydraulic tank capacity. Tag all the hydraulic lines to the hydraulic tank. Disconnect the suction tube to the lift pump and allow the hydraulic oil to drain out of the tank. Clean up any spilled oil. Disconnect the rest of the hydraulic lines to the tank. Plug the hydraulic lines to prevent dirt from entering the system.

4. Remove the capscrew holding the upper tank support bracket. Remove the support bracket. The hydraulic tank can now be removed by lifting the tank straight up.

Disassembly 1. Remove the breather/filler assembly from the top of the tank. Remove the strainer from the fill tube. See Figure 8-4.

2. Remove the three capscrews, lockwashers, nuts, flat washers and O-rings retaining the tank cover to the hydraulic tank. Remove the tank cover, gasket return line and filter from the tank.

3. Inspect all components for damage and replace any defec-tive item.

Installation 1. Locate the hydraulic tank in the lift truck.

2. Install the upper tank support bracket using the capscrew, washer and nut.

3. Install a new gasket on the hydraulic tank. Align the top cover assembly with the hydraulic tank and the gasket.

Install the three nuts and lockwashers to retain the top cover to the tank.

Sheet 8: Hydraulic System 4. Install the strainer in the tank cover.

5. Remove the plugs from the hydraulic lines. Connect all the hydraulic lines to the hydraulic tank.

6. Fill the hydraulic tank to the recommended level with the recommended hydraulic oil. See Section 2 -HYDRAULIC OILS. 7. Install the breather/filler assembly.

8. Remove the drain pan, close the drive unit compartment cover. Connect the battery.

9. Operate the lift truck through all functions. Check for oil leaks. Check the hydraulic tank for the correct oil level.

10. Close the drive unit compartment and install the drive unit cover on the lift truck.

TROUBLESHOOTING

Sheet 9: Mast MAST INTRODUCTION This section contains the removal, installation and adjustment procedures for the Triplex Hi-Vis mast assembly and operator's compartment used on the OS030EB and the SS030B lift trucks. This section includes the required maintenance and repair procedures. A troubleshooting chart is provided at the end of this section.

The mast is used to vertically raise and lower the operator's compartment and the load. The main lift cylinders are installed vertically in the mast. The main lift cylinders raise the vertical frames of the mast. These vertical frames are called mast weldments.

WARNING: The mast, operator's compartment and their components, are heavy. To help prevent damage or an injury, a lifting device must be used during all service procedures.

See Section 2 -GENERAL TRUCK AND LUBRICATION for the correct maintenance intervals and inspection procedures.

DESCRIPTION Triplex Mast The Triplex Hi-Vis Mast assembly has three main vertical frames called weldments. There is an outer mast weldment, a secondary mast weldment and an inner mast weldment. These weldments are assembled so they telescope. The outer mast weldment, attached to the lift truck frame, is stationary and does not move upward nor tilt forward or backward. The secondary mast weldment is located between the outer mast and inner mast weldments and moves within the outer mast. The inner mast weldment moves inside the secondary mast weldment. The operator's compartment moves inside the inner mast weldment.

The operator's compartment is raised with the two main lift cylinders. The mast is extended by two dual stage main lift cylinders attached to the secondary mast. These main lift cylinders control the movement of the secondary mast.

Two main lift chains transfer the force to the inner mast weldment.

Hoses connect the two hydraulic cylinders. When the telescopic weldments and the operator's compartment lift a load, forces are put on the mast assembly. To decrease friction caused by these forces, load rollers and wear strips are installed between the moving parts. The load rollers travel along the channels within the weldments.

OPERATION-TRIPLEX MAST The Triplex mast is designed so that all stages of the mast assembly operate proportionally. When the mast is raised three feet, the secondary mast and inner mast each has elevated one foot. The inner mast and the secondary mast lift at the same speed.

To extend the mast, oil from the main control valve flows to all cylinders at the same time. Platform lift chains connect to the crossmember of the inner mast weldment, are routed over two chain sheaves at the top of the inner mast weldment, and connect at the bottom of the operator's compartment. As the free main cylinders extends, the chains transfer the lifting motion to the operator's compartment causing the operator's compartment to move upward. The main lift cylinder raises the operator's compartment to the top of the inner mast weldment. The main cylinders must raise the operator's compartment, the load on the forks, and the weight of the secondary and inner mast weldments.

The two main cylinders control the movement of both the inner and secondary mast weldment as well as the operator's compartment. The base of each cylinder is located by a pin installed in the lower crossmember bracket of the outer mast weldment. The rods of each main cylinder are fastened to the top crossmember of the intermediate mast weldment with snap rings. As the cylinders extend, the secondary mast weldment is raised. A pair of lift chains connect near the top rear of the outer mast weldment, are routed over sheaves at the top of the intermediate mast weldment, and connect to the bottom of the inner mast weldment. As the secondary mast weldment is raised, the chains transfer the lifting motion to elevate the inner mast and operator's compartment.

During lowering, the main lift cylinders lower first because they support the greater amount of the total load. After the main lift cylinders have completely retracted, the free lift cylinder lowers. Each cylinder has a velocity fuse installed in its base to limit the lowering speed of the cylinder. Velocity fuses protect the operator and mast in the event of a hydraulic line failure. Hoses connect all of the cylinders to a single external lowering control valve that regulates the lowering speed under normal operating conditions. All oil from the lift cylinders flows through the lowering control valves to the hydraulic tank. The lowering control valve is located in the manifold attached to the bottom of the outer mast weldment.

Sheet 9: Mast SIMPLEX MAST The two-stage mast assembly has two weldments. They are the inner mast weldment and the outer mast weldment.

The inner mast weldment has a load roller on each bottom channel section. The load rollers travel along the channels within the outer mast weldment. The outer mast weldment has one load roller located at the top of the inside of each channel. The outside channels of the inner mast weldment travel on these load rollers during channel movement. The load rollers permit them to control the forces during movement of the mast. These forces are from the front, back and sides. Wear strips are used to control forces from front to back. The wear strips are installed at the top of the outer mast weldment. The wear strips are on the inside edge of the channels of the outer mast weldment. Shims and springs are used under the wear strips to keep the correct clearance between the weldments.

The two-stage mast assembly has two single-stage main cylinders that are installed vertically behind each channel of the outer mast weldment. The base of the main cylinders fit into pins that are located in the bottom crossmember of the outer mast weldment. Lock plates are used to position the main cylinders. These lock plates are bolted to the lower end of each outer mast channel. Removable supports for the main cylinders are bolted to the chain anchor weldments. The rods of each main cylinder are fastened to the top crossmember of the inner mast weldment with a snap ring. The inner mast weldment extends from the outer mast weldment as the cylinder rods extend. The weight of the weldment or operator platform causes the cylinder rods to retract.

Two hoist chains control the movement of the operator platform. The chains fasten to the chain anchor supports that are welded on each channel of the outer mast weldment. The chains go up and over the chain sheaves and then connect to the operator platform. The chain sheaves are installed at the inside of the channels near the top of the inner mast weldment. The chains transfer the force from the main cylinders to the operator platform.

OPERATION-SIMPLEX MAST As the rods in the main cylinders extend, they move the inner mast weldment out of the outer mast weldment. Since the chains are fastened to the inner mast weldment and the operator platform, the force from the cylinder rods transfer the lifting motion to the operator platform.

When the cylinder rods retract, the weight of the load, operator platform, and inner mast weldment pushes the fluid from the cylinders. The hydraulic fluid flows from the cylinders through the flow control valve located in the manifold to the hydraulic tank. Each main cylinder has a velocity fuse installed in its base. These velocity fuses control the lowering speed of a load if a hydraulic line should break.

Sheet 9: Mast

Figure 9-1 -Triplex Mast

Sheet 9: Mast

1.

2.

3.

4.

5.

6.

7.

Figure 9-2 -Operation of the Triplex Mast MAIN LIFT CYLINDER OUTER WELDMENT SECONDARY WELDMENT INNER WELDMENT MAIN LIFT CHAIN PLATFORM LIFT CHAIN OPERATOR'S COMPARTMENT

Operator's Compartment The operator's compartment contains the instrument panel and the controls necessary to operate the lift truck. The operator's compartment is equipped with an overhead guard and a tether line and belt for the safety of the operator.

The operator's compartment assembly moves within the vertical channels of the inner mast weldment. Load rollers keep the operator's compartment aligned between the inner channels of the inner mast weldment and decrease friction. Load forks are attached to the bottom of the operator's compartment. The operator is elevated with the load.

There is no load backrest extension.

SAFETY PROCEDURES WHEN WORKING NEAR THE MAST The following procedures must be used when inspecting or working near the mast. Additional precautions and procedures can be required when repairing or removing the mast.

WARNING: Mast parts are heavy and can move. Distances between parts are small. Serious injury or death can result if part of the body is hit by parts of the mast or the operator's compartment.

Never put any part of the body into or under the mast or operator's compartment unless all parts are completely lowered or a safety chain is installed. Also make sure that the power is off and the key is removed.

Put a "DO NOT OPERATE" tag in the operator compartment. Disconnect the battery and put a tag or lock on the battery connector.

Be careful of the forks. When the mast is raised, the forks can be at a height to cause an injury.

Do NOT climb on the mast or lift truck at any time. Use a ladder or personnel lift to ascend to or descend from the raised operator compartment, or to work on the mast. Do NOT use blocks to support the mast weldments nor to

Sheet 9: Mast restrain their movement. Mast repairs require disassembly and removal of parts and can require removal of the mast or operator's compartment.

Follow the repair procedures in this section.

WHEN WORKING NEAR THE MAST ALWAYS: Lower the mast and operator's compartment assembly completely. Make sure that all parts of the mast that move are fully lowered.

OR If parts of the mast must be in a raised position, install a safety chain to restrain the moving parts of the mast.

Connect moving parts to a part that does not move. Follow these procedures: a. Raise the operator's compartment to the top of the inner weldment (free lift cylinder is completely extended). Use a 3/8-inch minimum safety chain with a hook to fasten the top crossmember of the inner weldment to a crossmember on the operator's compartment. Put the hook on the steer tire side of the mast. Make sure the hook is completely engaged with a link in the chain. Make sure the safety chain is not slack and does not touch lift chains or chain sheaves, tubes, hoses, fittings or other parts on the mast. b. Raise the mast to align the bottom crossmember of the secondary weldment with a crossmember on the outer weldment. c.

Use a 3/8-inch minimum safety chain with a hook to fasten the crossmembers together so that the movable secondary member cannot lower. Put the hook on the load wheel side of the mast. Make sure the hook is completely engaged with a link in the chain. Make sure the safety chain does not touch lift chains or chain sheaves, tubes, hoses, fittings or other parts on the mast.

d. Slowly lower the mast until there is tension in both safety chains. return the lift/lower control to the neutral position. Move the key to the OFF position and remove the key from the key switch. Disconnect the battery and put a tag or lock on the battery connector. Install a "DO NOT REMOVE" tag on the safety chains.

Sheet 9: Mast

CHECKS Check Mast Operation WARNING: Pressurized hydraulic oil can be injected into the body by pressure. Do not try to locate hydraulic leaks by putting hands on pressurized hydraulic components.

1. Check for leaks in the hydraulic system (see below). Check the condition of the hydraulic hoses and tubes.

2. Slowly raise and lower the mast several times without a load. The mast components must raise and lower smoothly in the correct sequence.

NOTE: Some parts of the mast move at different speeds during raising and lowering.

3. The weldments and the operator's compartment assembly must lower completely.

4. Check that the controls for the operator's compartment operate the functions installed on the lift truck. Seethe symbols by each of the controls and refer to the OPERATING MANUAL for your lift truck. Make sure all of the hydraulic lines are connected correctly and do not leak.

Check for Leaks in Hydraulic System WARNING: Pressurized hydraulic oil can be injected into the body by pressure. Do not try to locate hydraulic leaks by putting hands on pressurized hydraulic components. Check for the location of high-pressure leaks by holding a piece of cardboard in front of the suspected area.

1. Slowly raise and lower the mast several times without a load. Put a capacity (see the Nameplate) load on the forks and raise and lower the load several times. Lower the load. Check for any external hydraulic oil leaks.

Repair as necessary.

2. On all models, raise the operator's compartment and the capacity load one metre (3 ft). Verify that there are no external hydraulic oil leaks. If the operator's compartment lowers slowly with the lift control in a NEUTRAL position there are leaks inside the hydraulic system. The maximum speed that the operator's compartment is allowed to lower is 50 mm (2 in) in ten minutes when the hydraulic oil is 30°C (90° F). If the oil temperature is 70°C (160°F), the maximum speed that the operator's compartment can lower is 150 mm (6 in) per ten minutes.

3. Check the lift cylinders for internal leaks. Remove the load from the forks. Install agate valve in the supply line between the control valve and the mast. Put a capacity load on the forks again. Raise the operator's compartment one metre (3 ft). Close the gate valve. If the operator's compartment or inner mast lowers slowly,

Sheet 9: Mast the seals in the lift cylinders have leaks.

Determine if cylinder is leaking by using gate valves in the supply lines to both cylinders to isolate the affected cylinder.

4. If the operator's compartment or inner mast does not lower, open the gate valve and check for movement again.

If the operator's compartment lowers when the gate valves are open, check for leaks in the hydraulic lines and fittings. If no leaks are found, the electro mechanical control valve can have a defect. Remove the load from the forks.

Remove Air from Hydraulic System NOTE: When you are removing air from the hydraulic system, make sure that all of the hydraulic fittings are tight and do not leak. Make sure that the level of oil in the hydraulic tank is correct.

Operate all of the mast functions to remove air from the hydraulic system. Fully extend and retract each cylinder rod.

When the cylinder rod reaches the end of its stroke, hold the control handle for approximately two seconds. Repeat the procedure as many times as necessary for each cylinder until the operation of both cylinders is smooth.

Check Lift Chains Cleaning and Inspection CAUTION: Do NOT use steam to clean the lift chains, sheaves or load rollers. The sheaves and bearings are sealed and permanently lubricated. Do not use compressed air on the bearings. The air can force the lubricant out of the bearings.

WARNING: Cleaning solvents can be flammable and toxic, and can cause skin irritation. Wear protection for eyes and skin. When using cleaning solvents, always follow the recommendations of the manufacturer.

1. Clean the lift chains using solvent. Inspect the lift chains for wear or damage. A lift chain becomes longer when it is worn. If a lift chain is 3% longer than a new lift chain, the lift chain must be replaced. Use a chain scale to measure the chains. If a chain scale is not available, check the lift chains with the measurements given in Figure 9-3.

WARNING: Never replace a partial section of a lift chain. Replace the complete chain. Never replace just one chain of a chain pair. Replace both chains.

2. Inspect the chain anchors and pins. Replace any parts that are worn or damaged.

3. Inspect the chain sheaves. Replace any parts that are worn or damaged.

Sheet 9: Mast

Figure 9-3 -Inspect the Lift Chains 1.

2.

3.

4.

5.

6.

7.

WORN PIN CRACKS EDGE WEAR HOLE WEAR LOOSE LEAVES DAMAGED PIN CORROSION

ADJUSTMENTS

Sheet 9: Mast The most important item to consider in maintaining the mast assembly is to keep the inner and secondary sections centered and level within the stationary channel of the outer mast. The mast weldments must be aligned parallel to each other during operation to ensure smooth operation and minimum wear.

The masts are designed with features that provide for normal wear and adjustments to compensate for any wear.

Whenever making any adjustments, it is important to take proper measurements to insure that the mast components are centered and level.

Wear plugs, an integral part of the load roller assembly, wear strips, and adjustable chain anchor pins allow for alignment and adjustment of the mast. Always adjust the wear plugs and wear strips for one weldment before making adjustments on other weldments.

Load Rollers Load rollers are found on each mast section. Tapered load rollers are used on the operator's compartment assembly. Load rollers allow the mast sections and operator's compartment to move up and down inside one another smoothly. The mast load rollers are comprised of a grease-sealed ball bearing and an adjustable inner wear plug. The tapered load rollers used on the operator's compartment do not have wear plugs. A snap ring is used to retain the load roller to the mounting bracket. The mounting brackets are welded to the mast assembly or operator's compartment.

Adjustments are made to the load rollers to keep side play to a minimum and to keep the mast weldments centered within their respective channels. The mast load rollers are adjusted by the adjustment of the wear plugs. Refer to ADJUST WEAR PLUGS. The tapered load rollers used on the operator's compartment do not have wear plugs and are adjusted using shims. Refer to OPERATOR'S COMPARTMENT INSTALLATION. Since load rollers contain a grease-sealed bearing, no lubrication of the roller itself is necessary. However, on the mast load rollers, the wear plugs come into contact with the central portion of the mast channel. Therefore, it is necessary to periodically apply grease to this area. In many applications, dirt from the environment collects on the greased section of the masts and creates hardened accumulations of dirt and grease which interferes with free movement of the rollers. If this condition is allowed to exist, the rollers will slide instead of roll up and down in the mast creating flat spots on the roller shell.

Steam clean the mast assembly periodically to remove any dirt accumulation. Apply new grease to all friction areas.

Inspect the rollers for cracks, flat spots or frozen bearings.

Figure 9-4 -Load Roller and Wear Plug Assembly 1.

2.

3.

4.

5.

6.

7.

LOAD ROLLER WEAR PLUG STUB SHAFT ELEVATING UPRIGHT SETSCREW NUT SEALED BEARING

Sheet 9: Mast Adjust Wear Plugs NOTE: Move the lift truck to an area with a smooth level floor before making any adjustments to make sure the adjustments are accurate.

Wear plugs should be adjusted to provide minimum clearance between the wear plug and the mast weldment.

Loosen the jam nut on the back side of the wear plug and turn the socket head setscrew in or out as required. A mast wear plug adjustment tool is available to make the wear plug adjustment easier. This tool can be obtained by contacting your nearest dealer.

Always adjust the wear plugs and wear strips for one mast weldment before making adjustments on other weldments.

WARNING: If a mast section binds or does not move freely during any adjustments, NEVER loosen the wear plugs without first raising the mast assembly high enough to remove any slack in the chains. Failure to do this may allow for a sudden drop of the binding mast section and could cause serious injury.

After each section has been adjusted, test the operation of the mast assembly by raising and lowering the mast assembly without a load. This will aid in determining if the wear plugs have been adjusted equally and that the mast does not bind. After each section has been successfully tested without a load, another test should be done with a load.

Figure 9-5 -Wear Plugs-Adjustment 1. YALE SPECIAL TOOL--5062050-00 2. ADJUSTMENT HANDLE 3. WELDMENT Proceed until all mast sections have been successfully adjusted and tested.

Adjust the wear plugs as follows: 1. Loosen the jam nut on the wear plug using Yale Special Tool 5062050-00, available from your Yale lift truck dealer. See Figure 9-5. Raise and lower the mast weldments several times to find the point of minimum clearance of the weldment.

2. Adjust the wear plugs to attain zero clearance between the wear plug and the weldment channel at the tightest point. Adjust wear plugs on opposite sides to keep the weldment in the center.

3. Adjust the clearance to approximately 0.5 mm (0.02 in) by turning the adjustment handle 1/8 turn counterclockwise. Keep the clearance between the weldments equal on both sides. Keep the weldments parallel to each other.

4. Tighten each jam nut without moving the setscrew.

WARNING: If a mast section binds or does not move freely during any adjustments, NEVER loosen the wear plugs without first raising the mast assembly high enough to remove the slack out of the chains. Failure to do

Sheet 9: Mast this may allow for a sudden drop of the binding mast section and could cause serious injury.

5. Raise and lower the weldments without a load. Check that there is minimum clearance, as described in Step 3, with free movement. If the weldments do not move smoothly, repeat this procedure until the wear plugs are properly adjusted.

6. Repeat Steps 1 through 6 for each weldment.

Lubricate Chains Clean and inspect the chains before lubrication. Use SAE 30 engine oil as a lubricant for the chains. The recommendation for adding lubricant is to remove the chains from the lift truck and soak them in oil.

ADJUST CHAINS WARNING: Mast parts are heavy and can move. Distances between parts are small. Serious injury or death can result if part of the body is hit by parts of the mast or the operator's compartment. Never put any part of the body into or under the mast or operator's compartment unless all parts are completely lowered or a safety chain is installed. Also make sure that the power is off and the key is removed. Refer to SAFETY PROCEDURES WHEN WORKING NEAR THE MAST. Adjustments must be made to both main lift chains. Each lift chain is adjusted at the chain anchor. Chains are adjusted for the following reasons: 1. Adjustments should be made to the chains to keep the chains at the proper tension. The chain tension must be the same for each chain of the chain set. Chains that have the same tension will move the same amount using the same pressure.

2. Each lift chain should support an equal load, to prevent too much load and wear on one chain of a pair.

3. The chain lengths must be equal for each chain set and the length must be correct for the mast height.

4. Mast weldments must move in the correct sequence.

5. The chains must be able to travel freely over chain sheaves through the raising and lowering cycle.

Adjust Platform Lift Chains WARNING: Mast parts are heavy and can move. Distances between parts are small. Serious injury or death can result if part of the body is hit by parts of the mast or the operator's compartment. Never put any part of the body into or under the mast or operator's compartment unless all parts are completely lowered or a safety chain is installed. Also make sure that the power is off and the key is removed. Refer to SAFETY PROCEDURES WHEN WORKING NEAR THE MAST. 1. Raise the operator's compartment assembly for access to the chain anchors near the top of the free lift cylinder.

Install safety chains. Refer to SAFETY PROCEDURES WHEN WORKING NEAR THE MAST, Page 9-4. Loosen both locknuts at the chain anchors to make any adjustments.

2. Check chain tension by pushing on both chains at the same time. If the tension is not the same, adjust the nuts on the chain anchors until the tension is the same and the distance (Step 1) is correct. When the tension is equal on both chains, the chain sheave assembly will be level.

3. Tighten the locknuts.

Sheet 9: Mast

Figure 9-6 -Chain Adjustment 1.

2.

3.

4.

5.

6.

7.

8.

9.

SECONDARY WELDMENT CHAIN SHEAVE LIFT CHAIN COTTER PIN ANCHOR PIN CHAIN ANCHOR LOCKNUT OUTER WELDMENT ADJUSTMENT NUT

NOTE: When the chain adjustments are complete, make sure that the cotter pin at the bottom of the chain anchor can be installed under the adjustment nut. If there is no room to install the cotter pin, the chains are too short. Install the correct chains. Make sure that the locknuts on the chain anchors are tight against the mount plate. If there are not enough threads on the chain anchor for correct adjustment, new chains are too long or old chains are too worn.

Links can be removed from old chains if the chains are less than 3% longer than the correct new chain. Replace old chains that are too long or new chains that are not the correct length.

4. Check the mast operation. Refer to CHECKS -CHECK MAST OPERATION.

Adjust Main Lift Chains WARNING: Mast parts are heavy and can move. Distances between parts are small. Serious injury or death can result if part of the body is hit by parts of the mast or the operator's compartment. Never put any part of the body into or under the mast or operator's compartment unless all parts are completely lowered or a safety chain is installed. Also make sure that the power is off and the key is removed. Refer to SAFETY PROCEDURES WHEN WORKING NEAR THE MAST. NOTE: The free lift chains must be adjusted before adjusting the main lift chains.

1. Check the main lift chains for equal tension by pushing on both chains at the same time. If the tension is not the same, adjustment is required. The adjustment nuts are at the chain anchors near the top of the outer weldment.

2. To adjust the tension, loosen both locknuts at the chain anchor. Adjust the nuts at the chain anchor until the tension is the same on both sides. Tighten the locknuts.

NOTE: When the chain adjustments are complete, make sure that the cotter pin at the bottom of the chain anchor can be installed under the adjustment nut. If there is no room to install the cotter pin, the chains are too short. Install the correct chains. Make sure that the locknuts on the chain anchors are tight against the mount plate. If there are not enough threads on the chain anchor for correct adjustment, new chains are too long or old chains are too worn.

Links can be removed from old chains if the chains are less than 3% longer than the correct new chain. Replace old chains that are too long or new chains that are not the correct length.

3. Check the mast operation. Refer to CHECKS -CHECK MAST OPERATION.

Sheet 9: Mast Adjust Wear Strips The wear strips and shims are fastened to the lower guide blocks of weldments that move. The wear strips and shims are adjusted for the following reasons: •

For minimum clearance to prevent too much side movement of the weldments.

•

To keep the weldments parallel.

NOTE: The wear plugs and lift chains must be adjusted before the wear strips are checked, replaced, or adjusted.

Check and adjust the wear strips as follows: WARNING: Mast parts are heavy and can move. Distances between parts are small. Serious injury or death can result if part of the body is hit by parts of the mast or the operator's compartment. Never put any part of the body into or under the mast or operator's compartment unless all parts are completely lowered or a safety chain is installed.

Also make sure that the power is off and the key is removed. Refer to SAFETY PROCEDURES WHEN WORKING NEAR THE MAST. 1. Move the lift truck to an area with a smooth level floor before making adjustments to insure adjustments are accurate. Raise the operator's compartment to gain access to the wear strips. Install safety chains as described in SAFETY PROCEDURES WHEN WORKING NEAR THE MAST, Page 9-4.

2. Remove the capscrews, washers, wear strips and shims. Replace all worn or damaged parts. One wear strip and one shim on each side are usually the correct adjustment. There must be the same number of shims under the wear strip on both sides of the weldment. Equal shims will keep the weldment parallel with equal clearance.

Figure 9-7 -Typical Wear Strip Assembly 1.

2.

3.

4.

5.

CAPSCREW WASHER WEAR STRIP SHIM WELDMENT CHANNEL

3. Use a prybar to move the weldment to install shims for minimum clearance. Install the shims and new wear strips as shown in Figure 9-7. Wear strips and shims on the inner weldment can be used on either side. There are right and left wear strips and shims on the secondary weldments. Remove the safety chains.

WARNING: If a mast section binds or hangs up during any adjustments, NEVER loosen the wear plugs without first raising the mast assembly high enough to remove the slack out of the chains. Failure to do this may allow for a sudden drop of the binding mast section and could cause serious injury.

Sheet 9: Mast 4. Check that the mast operates correctly as described in CHECK THE OPERATION OF THE MAST at the beginning of this section.

NOTE: Refer to Section 2 of this manual for the recommended maintenance and inspection intervals for the mast, hydraulic cylinders, forks and operator's compartment.

MAINTENANCE WARNING: Lower the lift mechanism completely. Never allow anyone under a raised operator's compartment or forks. Do not put any part of your body in or through the mechanism unless all parts of the mast are completely lowered, the key switch is in the OFF position, and the battery is disconnected.

WARNING: Mast parts are heavy and can move. Distances between parts are small. Serious injury or death can result if part of the body is hit by parts of the mast or the operator's compartment. Never put any part of the body into or under the mast or operator's compartment unless all parts are completely lowered or a safety chain is installed. Also make sure that the power is OFF and the key is removed. Refer to SAFETY PROCEDURES WHEN WORKING NEAR THE MAST. WARNING: Some parts can be damaged by welding and cause an injury. Get authorization and instructions from your Yale lift truck dealer before welding on the mast or operator's compartment.

WARNING: Be careful when removing or installing snap rings. These snap rings are large and can come loose during removal or installation with enough force to cause an injury. Always use the correct snap ring pliers and wear eye and face protection during removal or installation.

OPERATOR'S COMPARTMENT WARNING: Lift chains, hoses and cables can roll over the sheaves to fall and cause an injury if the ends are not fastened. Keep control of the ends of the lift chains, hoses and cables as they are removed. Use wire to temporarily secure the ends of the lift chains, hoses or cables.

Removal 1. Park the lift truck with a minimum of ten feet of clearance in front of the truck. Be sure the steer tire is positioned for straight travel.

2. Raise the operator's compartment until the floor of the operator's compartment is even with the top of the drive unit compartment.

3. Use safety chains to secure the crossmember of the operator's compartment to a crossmember on the outer stationary weldment.

4. Turn the key to the OFF position, disconnect the battery and separate the connectors.

WARNING: Mast parts are heavy and can move. Distances between parts are small. Serious injury or death can result if part of the body is hit by parts of the mast or the operator's compartment. Never put any part of the body into or under the mast or operator's compartment unless all parts are completely lowered or a safety chain is installed. Also make sure that the power is off and the key is removed. Refer to SAFETY PROCEDURES WHEN WORKING NEAR THE MAST. 5. Disconnect the spring holding tension on the wire take-up assembly and remove the spring from the truck.

Sheet 9: Mast

Figure 9-8 -Wire Take-up Tension Spring 6. Locate the clamp at the bottom of the mast-side of the operator's compartment that secures the wire take-up assembly to the floor of the operator's compartment. Remove the bolt that secures the clamp to the operator's compartment and remove the clamp from the truck.

7. Position blocks under the operator's compartment and at both ends of each fork in order to support the weight of the operator's compartment and forks when lowered.

8. Remove the safety chains preventing the mast and operator's compartment from moving.

9. Connect the battery. Lower the operator's compartment on to the blocks positioned in Step 7. Make sure the operator's compartment and forks are securely supported at both ends and level and stable.

10. Support the operator's compartment from above to prevent the operator's compartment from tipping after it is removed from the truck. As an alternative, place a load on the top of the forks, evenly spaced between the blocks, to prevent the operator's compartment from tipping.

11. Disconnect the battery and separate the connectors.

12. Open the drive unit compartment.

WARNING: The capacitor in the SCR controller can hold an electrical charge after the battery is disconnected.

To prevent electrical shock and injury, discharge the capacitor before inspecting or repairing any component in the drive unit compartment. Wear safety glasses. Make certain the battery has been disconnected. Use a jumper wire between the two terminals to discharge capacitor C1. Block the drive wheels.

13. Discharge the capacitor.

WARNING: Lift chains, hoses and cables can roll over the sheaves, fall and cause an injury if the ends are not fastened. Keep control of the ends of the lift chains, hoses and cables as they are removed. Use wire to temporarily connect the ends of the lift chains, hoses or cables.

14. Close the drive unit compartment and connect the battery.

WARNING: The operator's compartment may be unstable when removed and can fall and cause an injury.

Support the operator's compartment from above with an overhead hoist or be sure that the operator's compartment is securely supported from below and cannot tip over.

15. Using caution to avoid pinching any hoses or cables, slowly raise the mast with the lift/lower control until the inner mast section is clear of the load rollers of the operator's compartment.

WARNING: Mast parts are heavy and can move. Distances between parts are small. Serious injury or death can result if part of the body is hit by parts of the mast or the operator's compartment. Never put any part of the body into or under the mast or operator's compartment unless all parts are completely lowered or a safety chain is installed. Also make sure that the power is OFF and the key is removed. Refer to SAFETY PROCEDURES WHENWORKING NEAR THE MAST. 16. Using caution to avoid stretching or snagging any hoses, wires or cables, slowly move the truck forward with the traction control in the operator's compartment until the bottom of the mast is clear of the operator's compartment load rollers.

Sheet 9: Mast 17. Disconnect the battery and separate the connectors.

18. Remove the dash cover in the operator's compartment.

19. Disconnect the two connectors of the wire take-up harness in the operator's compartment.

20. Remove the two screws securing the wire take-up strain relief fitting to the operator's compartment.

WARNING: Care must be taken to adequately support the operator's compartment at all times to prevent tipping.

Installation The operator's compartment is installed similar to the way it was removed. The mast on the lift truck must be secured in the raised position with chains high enough to allow the lift truck to be maneuvered into position above the load rollers of the operator's compartment. Follow the procedure below: 1. Align the operator's compartment and the lift truck into the proper position for installation. The mast inner weldment should be positioned above the load rollers of the operator's compartment.

2. Disconnect the battery and separate the connectors.

3. Insert the wire take-up harness and strain relief through the opening in the center of the mast side of the operator's compartment. Secure the strain relief with the two screws. Connect the wire harness in the operator's compartment by plugging in the two connectors.

4. Open the drive unit compartment.

WARNING: The capacitor in the SCR controller can hold an electrical charge after the battery is disconnected.

To prevent electrical shock and injury, discharge the capacitor before inspecting or repairing any component in the drive unit compartment. Wear safety glasses. Make certain the battery has been disconnected.

Use a jumper wire between the two terminals to discharge capacitor C1. Block the drive wheels.

5. Discharge the capacitor.

6. Slowly lower the mast inner weldment onto the load rollers of the operator's compartment using the manual lowering valve on the hydraulic pump. Gradually turn the valve clockwise and wait until the mast is completely lowered. Use caution to avoid pinching any hoses or cables. Close the manual lowering valve by rotating the valve counterclockwise to the stop.

WARNING: Be careful when removing or installing snap rings. These snap rings are large and can come loose during removal or installation with enough force to cause an injury. Always use the correct snap ring pliers and wear eye and face protection during removal or installation.

7. Check the adjustment of the tapered load rollers of the operator's compartment. Check for zero clearance at the tightest point of travel within the mast channel. Adjustment to the tapered load rollers is made using shims behind each load roller as required. Use caution when removing the snap ring retaining the load roller to the bracket. The operator's compartment must be centered and parallel with the mast inner weldment within 1.5 mm (0.060 in.).

WARNING: Mast parts are heavy and can move. Distances between parts are small. Serious injury or death can result if part of the body is hit by parts of the mast or the operator's compartment. Never put any part of the body into or under the mast or operator's compartment unless all parts are completely lowered or a safety chain is installed. Also make sure that the power is OFF and the key is removed. Refer to SAFETY PROCEDURES WHEN WORKING NEAR THE MAST. 8. Remove the safety chains preventing the mast and operator's compartment from moving.

9. Close the drive unit compartment and connect the battery.

10. Raise the operator's compartment using the lift/lower control until the floor of the operator's compartment is even with the top of the drive unit compartment.

WARNING: Mast parts are heavy and can move. Distances between parts are small. Serious injury or death can result if part of the body is hit by parts of the mast or the operator's compartment. Never put any part of the body into or under the mast or operator's compartment unless all parts are completely lowered or a safety chain is

Sheet 9: Mast installed. Also make sure that the power is OFF and the key is removed. Refer to SAFETY PROCEDURES WHEN WORKING NEAR THE MAST. 11. Install the clamp at the bottom of the mast-side of the operator's compartment that secures the wire take-up assembly to the floor of the operator's compartment.

12. Install the spring that holds tension on the wire take-up assembly.

13. Check the mast operation. Refer to CHECKS -CHECK MAST OPERATION.

FORKS Each fork is connected to the operator's compartment by a pin near the edge of the operator's compartment. The pin fits through a tube welded to the top of the fork and holes in the operator's compartment assembly. It is necessary to raise the operator's compartment to access the forks pins.

WARNING: Forks are heavy and can cause an injury. Do not try to remove forks without using a lifting device.

Removal WARNING: Mast parts are heavy and can move. Distances between parts are small. Serious injury or death can result if part of the body is hit by parts of the mast or the operator's compartment. Never put any part of the body into or under the mast or operator's compartment unless all parts are completely lowered or a safety chain is installed. Also make sure that the power is off and the key is removed. Refer to SAFETY PROCEDURES WHEN WORKING NEAR THE MAST.

Figure 9-9 -Fork Assembly 1.

2.

3.

4.

5.

6.

7.

FORK PIN SNAP RING SHIM SPACER WASHER WASHER

1. Raise the mast to gain access to the fork pins.

2. Support the fork using a hoist and sling and/or jack.

WARNING: Be careful when removing or installing snap rings. These snap rings are large and can come loose during removal or installation with enough force to cause an injury. Always use the correct snap ring pliers and wear eye and face protection during removal or installation.

3. Remove the snap ring from the end of the fork pin.

4. Remove the fork pin and washers. Guide the fork out of the fork retainer and carefully lower it to the floor.

NOTE: If shims are used, mark them for installation during fork installation.

Installation

Sheet 9: Mast WARNING: Forks are heavy and can cause an injury. Do not try to install forks without using a lifting device.

1. Raise the mast to gain access to the fork pins.

WARNING: Mast parts are heavy and can move. Distances between parts are small. Serious injury or death can result if part of the body is hit by parts of the mast or the operator's compartment. Never put any part of the body into or under the mast or operator's compartment unless all parts are completely lowered or a safety chain is installed. Also make sure that the power is off and the key is removed. Refer to SAFETY PROCEDURES WHEN WORKING NEAR THE MAST. 2. Support the fork using a hoist and sling and/or jack.

3. Raise the fork into the fork retainer and align the fork tube with the fork pin support holes under the operator's compartment.

NOTE: If shims are used, install them in the original positions.

4. Install the fork pins and washers.

WARNING: Be careful when removing or installing snap rings. These snap rings are large and can come loose during removal or installation with enough force to cause an injury. Always use the correct snap ring pliers and wear eye and face protection during removal or installation.

5. Install the snap ring on the fork pins.

PALLET CLAMP WARNING: Mast parts are heavy and can move. Distances between parts are small. Serious injury or death can result if part of the body is hit by parts of the mast or the operator's compartment. Never put any part of the body into or under the mast or operator's compartment unless all parts are completely lowered or a safety chain is installed. Also make sure that the power is off and the key is removed. Refer to SAFETY PROCEDURES WHEN WORKING NEAR THE MAST. The pallet clamp is designed to automatically engage as the center of a pallet slides into the clamp. To release the clamp, depress the pallet clamp pedal. Refer to Figure 9-10. If the clamp is not working properly, adjust the actuating rods beneath the operator's compartment. The clamp should be adjusted so the gap is 12.7 mm (1 /2 in.) in the initial position and 76 mm (3in.) maximum opening. Refer to PALLET CLAMP, Page 2-4 for instructions on checking the operation of the pallet clamp.

Figure 9-10 -Pallet Clamp

TRIPLEX MAST ASSEMBLY Removal 1. Remove the operator's compartment. Refer to OPERATOR'S COMPARTMENT -REMOVAL. 2. Operate the lift/lower control handle to raise the inner weldment high enough to access the four capscrews and

Sheet 9: Mast washers that fasten the bottom of the mast to the truck frame. DO NOT remove the capscrews at this time.

WARNING: Mast parts are heavy and can move. Distances between parts are small. Serious injury or death can result if part of the body is hit by parts of the mast or the operator's compartment. Never put any part of the body into or under the mast or operator's compartment unless all parts are completely lowered or a safety chain is installed. Also make sure that the power is off and the key is removed. Refer to SAFETY PROCEDURES WHEN WORKING NEAR THE MAST. 3. Install safety chains to keep the mast components from moving.

4. Remove the four capscrews and washers that fasten the bottom of the mast outer weldment to the truck frame.

Do NOT disconnect any hydraulic fittings.

5. Disconnect the spring holding tension on the wire take-up assembly and remove the spring from the truck.

6. Remove the safety chains installed in Step 3. Carefully operate the lift/lower control handle to fully lower the operator's compartment and inner weldment. Make sure that all hydraulic pressure is removed from the system.

7. Remove the bolt from above the wire take-up assembly sheave. Slip the wire take-up assembly off of the sheave and support the wire from above at the stationary mast with a bungee cord.

8. Disconnect the hydraulic hose to the mast at the fitting attached to the outside of the drive unit compartment.

Cap the hose and the fitting to avoid excessive hydraulic fluid loss. Secure the disconnected hose to the mast so the hose will be out of the way when the mast is removed.

9. Disconnect the battery and separate the connectors.

10. Open the drive unit compartment.

WARNING: The capacitor in the SCR controller can hold an electrical charge after the battery is disconnected.

To prevent electrical shock and injury, discharge the capacitor before inspecting or repairing any component in the drive unit compartment. Wear safety glasses. Make certain the battery has been disconnected. Use a jumper wire between the two terminals to discharge capacitor C1. Block the drive wheels.

11. Discharge the capacitor.

12. Disconnect the three connectors of the wire take-up harness and proximity sensor harness in the drive unit compartment.

13. Locate the clamp at the bottom of the mast-side of the operator's compartment that secures the wire take-up assembly to the floor of the operator's compartment. Remove the bolt that secures the clamp to the operator's compartment and remove the clamp from the truck.

14. Mark the trunnion caps so they can be reassembled in the same position and on the same trunnion from which they are removed. Use chains to connect a crane or other lifting device to the top of the mast assembly. Operate the crane until it gives support to the weight of the mast assembly. Move the crane to a position so that the mast assembly will be lifted vertically. Make sure the chains will not damage the sheaves or other parts of the mast assembly. Make sure the chains and crane have the capacity to lift approximately 2000 kg (4500 Ibs). Use safety chains to fasten all the mast weldments together so that they cannot move. Install a chain or sling to the operator's compartment to keep the mast assembly from tipping during removal. Remove the four capscrews that fasten the trunnion caps.

15. Use the crane or overhead hoist to raise the mast assembly high enough to clear the trunnions.

16. Move the mast assembly away from the truck. Place the mast securely on a level floor and support the mast to prevent accidental movement.

Cleaning and Inspection WARNING: Cleaning solvents can be flammable and toxic, and can cause skin irritation. Wear protection for eyes and skin. When using cleaning solvents, always follow the recommendations of the manufacturer.

1. Clean the mast weldments with steam or solvent.

2. Inspect the sliding and rolling surfaces of the channels for damage (dents) and wear (grooves). Inspect all welds for cracks.

Sheet 9: Mast

Figure 9-11 -Triplex Mast Assembly 1.

2.

3.

4.

INNER WELDMENT SECONDARY WELDMENT OUTER WELDMENT MAIN LIFT CYLINDER A. LOCK PLATE B. RETAINER 5. CHAIN ANCHOR 6. CHAIN SHEAVE ASSEMBLY (RH) A. CHAIN SHEAVE B. BALL BEARING C. SNAP RING 7. MAIN LIFT CHAIN 8. LOAD ROLLER 9. FLOW REGULATOR HOUSING 10. FLOW REGULATOR

Sheet 9: Mast 11. HYDRAULIC ACCUMULATOR 12. HYDRAULIC HOSE (MAIN LIFT)

Installation WARNING: Mast parts are heavy and can move. Distances between parts are small. Serious injury or death can result if part of the body is hit by parts of the mast or the operator's compartment. Never put any part of the body into or under the mast or operator's compartment unless all parts are completely lowered or a safety chain is installed. Also make sure that the power is off and the key is removed. Refer to SAFETY PROCEDURES WHEN WORKING NEAR THE MAST. 1. Use chains to connect a crane or other lifting device to the top of the mast assembly. Operate the crane until it gives support to the weight of the mast assembly. Move the crane to a position so that the mast assembly will be suspended vertically. Make sure the chains will not damage the sheaves or other parts of the mast assembly.

Make sure the chains and crane have the capacity to lift approximately 2000 kg (4500 Ibs). Use safety chains to fasten all the mast weldments together so that they cannot move. Install a chain or sling to the operator's compartment to keep the mast assembly from tipping during installation.

2. Use the crane or overhead hoist to raise the mast assembly high enough to clear the trunnion support on the truck. Carefully move the mast assembly in position above the trunnion supports.

3. Carefully lower the mast onto the trunnion supports. Be sure the bottom of the mast outer weldment is against the truck frame at the bottom.

4. Assemble the trunnion caps onto the trunnion supports taking care to install them exactly the same way as they were removed. Tighten the trunnion cap bolts to a torque value of 203 Nm (150 Ib \ ft).

5. Disconnect the battery and separate the connectors.

6. Open the drive unit compartment.

WARNING: The capacitor in the SCR controller can hold an electrical charge after the battery is disconnected.

To prevent electrical shock and injury, discharge the capacitor before inspecting or repairing any component in the drive unit compartment. Wear safety glasses. Make certain the battery has been disconnected. Use a jumper wire between the two terminals to discharge capacitor C1. Block the drive wheels.

7. Discharge the capacitor.

8. Carefully route the three connectors from the wire take-up harness and proximity sensor harness through the opening in the drive unit compartment and connect them to the proper mating connectors.

9. Connect the hydraulic line to the mast at the fitting attached to the outside of the drive unit compartment.

10. Remove the safety chains installed in Step 1.

11. Close the drive unit compartment and connect the battery.

12. Operate the lift/lower control handle to raise the operator's compartment and inner weldment high enough to expose the mast mounting bolt holes at the bottom of the outer mast weldment.

WARNING: Mast parts are heavy and can move. Distances between parts are small. Serious injury or death can result if part of the body is hit by parts of the mast or the operator's compartment. Never put any part of the body into or under the mast or operator's compartment unless all parts are completely lowered or a safety chain is installed. Also make sure that the power is off and the key is removed. Refer to SAFETY PROCEDURES WHEN WORKING NEAR THE MAST. 13. Install the four capscrews and washers that secure the bottom of the mast outer weldment to the truck frame.

Tighten to a torque value of 203 Nm (150 Ib \ ft).

14. Install the clamp at the bottom of the mast-side of the operator's compartment that secures the wire take-up assembly to the floor of the operator's compartment.

15. Install the spring that holds tension on the wire take-up assembly.

16. Remove the safety chains.

Sheet 9: Mast 17. Check the mast operation. Refer to CHECKS -CHECK MAST OPERATION.

Inner and Secondary Mast Assemblies-Removal and Installation 1. The load rollers and wear plugs must be removed to remove the inner or secondary weldments. Refer to LOAD ROLLERS AND WEAR PLUGS, REMOVAL AND INSTALLATION. 2. The lift chains, hoses and electrical cable must also be removed to remove the inner or secondary weldments.

To remove the lift chains, hoses and sheaves, refer to TRIPLEX LIFT CHAINS, REMOVAL AND INSTALLATION, and TRIPLEX CHAIN SHEAVES, DISASSEMBLY AND AS-SEMBLY 3. Use safety chains to fasten the secondary weldment to the outer weldment. Use a crane or lifting device to support the inner weldment while sliding it out of the secondary weldment.

4. Remove the safety chains that fasten the secondary weldment to the outer weldment. Use a crane or lifting device to support the secondary weldment while sliding it out of the outer weldment.

5. Install the load rollers and wear plugs during assembly of the mast weldments.

Replace Hoses 1. To replace any hydraulic hose, fully lower the operator's compartment. Make sure that the system does not have hydraulic pressure by holding the lift/lower control for approximately five seconds to release the pressure. Make sure the hydraulic pump does NOT operate. Move the key to the OFF position. Disconnect the battery and put a tag or lock on the battery connector.

NOTE: Access can be difficult for some fittings. If necessary, operate the system to move mast weldments or the operator's compartment. Make sure to follow the SAFETY PROCEDURES WHEN WORKING NEAR THE MAST, Page 9-4, after moving components BEFORE starting work. Also make sure the system does not have pressure as described in Step 1.

2. Disconnect hoses, drain any excess oil into a container and install caps to prevent dirt from entering the hydraulic system.

3. Replace the hose. Operate the system to remove all the air from the oil and to check for leaks.

4. Check the mast operation. Refer to CHECKS -CHECK MAST OPERATION, page 9-5.

MAIN CYLINDERS Removal NOTE: It is necessary to remove the mast assembly from the truck to remove the main cylinders.

1. Remove the mast assembly. Refer to TRIPLEX MAST ASSEMBLY, REMOVAL. 2. Secure the mast in a horizontal position.

WARNING: The mast weldments can move and cause an injury even if the mast assembly has been removed from the lift truck. Make sure the mast assembly is level to prevent the components from moving without being moved. Use safety chains to prevent movement after components are in the correct position.

3. Remove the safety chains that fasten the mast weldments together and use a prybar to carefully and slowly move the secondary weldment approximately 75 mm (3 in) out of the outer weldment.

4. Install a sling and crane to support the cylinder. Remove the capscrews, washers and lock plate at the base of one main cylinder.

WARNING: Be careful when removing or installing snap rings. These snap rings are large and can come loose during removal or installation with enough force to cause an injury. Always use the correct snap ring pliers and wear eye and face protection during removal or installation.

5. Remove the snap ring, back-up washer, rubber bushing and shims (if applicable) that fasten the cylinder rod to the secondary weldment. If shims are used, make a note of the shim arrangement. Normally, the shim arrangement for the replacement cylinder will be similar.

Sheet 9: Mast 6. Remove the hose or tube between the main cylinder and the manifold. If necessary, use a prybar to carefully move the operator's compartment and mast weldments for access. Install a cap on the regulator fitting to prevent leakage.

7. Remove the main cylinder retainer, capscrews and washers.

8. Push the cylinder toward the top of the mast assembly to move the cylinder off the locating dowel pin. Continue to push the cylinder so that the rod moves into the cylinder to allow removal from the secondary weldment.

9. Repeat Steps 4 through 8 to remove the other main cylinder.

Installation 1. Install the cylinder onto the locating dowel pin.

2. Install the cylinder retainer, capscrews, and washers.

3. Install the hydraulic hose to the cylinder.

WARNING: Be careful when removing or installing snap rings. These snap rings are large and can come loose during removal or installation with enough force to cause an injury. Always use the correct snap ring pliers and wear eye and face protection during removal or installation.

4. Install the snap ring, back-up washer, rubber bushing, and shims (if applicable), that fasten the cylinder rod to the secondary weldment. If shims are used, be sure to install them in the same way as they were removed.

5. Install the capscrews, washers and lock plate at the base of one main cylinder.

DISASSEMBLY OF A LIFT CYLINDER CAUTION: Carefully disassemble the lift cylinders so that the piston rods and sliding surfaces are not damaged.

NOTE: The lift cylinders are disassembled from the rod end of the cylinder shell.

1. Loosen the retainer with a spanner. Remove the retainer from the shell.

2. Pull the rod and piston assembly from the shell. Drain the hydraulic oil into a container.

3. Remove the retainer from the piston rod. Remove and discard the O-rings, seals, and wear rings.

WARNING: Be careful when removing or installing snap rings. These snap rings are large and can come loose during removal or installation with enough force to cause an injury. Always use the correct snap ring pliers and wear eye and face protection during removal or installation.

4. Remove the snap ring, washer, and check valve from the base of the piston.

5. Clean all the parts. Check the sliding surfaces for damage. Install new parts if the damaged parts cannot be repaired.

ASSEMBLY OF A LIFT CYLINDER 1. Lubricate all internal parts of the lift cylinder with clean hydraulic oil or packing lubricant (Yale Part No. 504234269). Use new O-rings, seals, and wear rings.

WARNING: Be careful when removing or installing snap rings. These snap rings can come loose during removal or installation with enough force to cause an injury. Always use the correct snap ring pliers and wear eye and face protection during removal and installation.

Sheet 9: Mast

Figure 9-12 -Lift Cylinder 1. ROD WIPER 2. SEAL 3. GLAND 4. RING 5. TUBE WELDMENT 6. SPACER 7. VELOCITY FUSE 8. SNAP RING (2) 9. WEAR RING 10. FLOATING PISTON 11. BACK-UP RING 12. SHIM 13. WASHER 14. CHECK VALVE 15. RING 16. PISTON ROD 2. Install the check valve and O-ring in the base of the piston. Make sure the arrow on the check valve is towards the base of the piston. Install the washer and snap ring for the check valve.

CAUTION: A difficult and important step in assembling lift cylinders is the correct installation of the seals. Most lift cylinder maintenance is caused by seal leaks. Do not damage any parts during assembly.

NOTE: The main lift cylinder packing kits are furnished with sleeves to aid in assembly of the seal onto the piston and to install the piston assembly into the shell. Use the sleeves, along with the furnished instruction sheet, to insure proper assembly.

3. Install the wear ring, piston seal and back-up ring onto the piston assembly. If a spacer is used, install it.

4. Carefully push the piston and rod assembly into the shell.

5. Install the rod seal ring and wiper into the retainer. Install the O-ring and back-up ring on the outside of the retainer.

6. Carefully install the gland on the piston rod. Engage the threads and tighten the retainer in the shell until it is tight. Use a correct spanner. Do not hit the gland with a hammer and driver.

7. Install the velocity fuse. Make sure the special washer and the spring are installed correctly. A wrong installation

Sheet 9: Mast can cause the load to lower too fast.

LOAD ROLLERS AND WEAR PLUGS-REMOVAL AND INSTALLATION 1. Remove the operator's compartment and mast assembly. Refer to OPERATOR'S COMPARTMENT, REMOVAL and TRIPLEX MAST ASSEMBLY, REMOVAL. Remove the main lift cylinders. Refer to MAIN CYLINDERS-REMOVAL AND INSTALLATION. The mast assembly must be horizontal.

Figure 9-13 -Triplex Load Rollers 1.

2.

3.

4.

5.

6.

7.

8.

OUTER WELDMENT SECONDARY WELDMENT INNER WELDMENT LOAD ROLLER SNAP RING WEAR PLUG SET SCREW JAM NUT

WARNING: The mast weldments can move and cause an injury even if the mast assembly has been removed from the lift truck. Make sure the mast assembly is level to prevent the components from moving without being moved. Use safety chains to prevent movement after components are in the correct position.

2. Remove the safety chains that fasten the mast weldments together and use a prybar to carefully and slowly

Sheet 9: Mast move the correct mast weldment for access to the load rollers. The inner weldment load rollers are at the bottom. The load rollers for the outer weldment are at the top. The load rollers for the secondary weldment are at the top and the bottom of the weldment. Use safety chains to fasten the inner weldment to the outer weldment so that they do not separate completely.

NOTE: If the inner weldment and the secondary weldment will be disassembled from the outer weldment, do not install the load rollers at this time.

WARNING: Be careful when removing or installing snap rings. These snap rings are large and can come loose during removal or installation with enough force to cause an injury. Always use the correct snap ring pliers and wear eye and face protection during removal or installation.

3. Always install safety chains to prevent the weldments from moving BEFORE starting to replace any load roller.

Remove the snap rings that fasten the load rollers.

NOTE: Replace wear plugs at this time to save the cost of removal and disassembly of the mast assembly for wear plug replacement.

4. Use a prybar to remove the load roller from the mast weldment. See Figure 9-14.

Figure 9-14 -Removing Load Roller 1. LOAD ROLLER WITH SNAP RING REMOVED 2. PRYBAR 5. Use a cloth to clean each load roller. Inspect the load rollers for cracks, flat spots or bearings that do not turn freely. Replace any roller that shows wear or is damaged.

6. Adjust the wear plugs after all load rollers and wear plugs are replaced. See CHECKS AND ADJUSTMENTS. The wear plugs are adjusted after the mast assembly is installed on the lift truck.

TROUBLESHOOTING-MAST

Sheet 9: Mast