Connecting Rods - Crawlers to Truck Frame

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Engineering Data

Connecting Rods - Crawlers to Truck Frame

Engineering Data

Torque Nut Removal Procedure

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THE PROPER REMOVAL OF TORQUE NUTS REQUIRES FOLLOWING STRICT PROCEDURES. LONGER ANCHOR BOLTS AND RODS REQUIRE GREATER CARE. If some jackbolts are completely unloaded prematurely, the remaining jackbolts will carry the entire load of the fastener. This may cause the jackbolts to become extremely hard to turn or even deformed.

NOTE: It is a good practice to spray the entire fastener and jackbolts with a penetrating type lubricant prior to attempting removal. This step will be critical if rust exists on the components.

1. Turn the first jackbolt counter-clockwise until it feels loose, but no more than 1/2 turn. 2. Repeat the loosening with the rest of the jackbolts. Use the reverse of the star pattern used to tighten the jackbolts. This will minimize loading on the last few jackbolts. 3. Repeat the entire loosening pattern, turning each jackbolt no more than 1/2 turn at a time, until the torque nut can be spun off the rod or bolt by hand.

After removal of the torque nut:

• Remove all jackbolts from the torque nut. Clean, inspect and lubricate the toque nut, hardened washer and the jackbolts for later reassembly.

NOTE: On smaller torque nut fasteners it may be possible to utilize impact tools to speed removal after performing step 2 above. However, DO NOT USE IMPACT TOOLS FOR THE INITIAL LOOSENING PROCEDURE. Longer anchor bolts may require several repetitions of the initial loosening process prior to switching to impact tools for assistance.

Thread Lubrication

For the main studs of torque nut fasteners any standard anti-seize compound may be used. A thin, brush-on type application, or aerosol spray lubricant is acceptable.

Jackbolts are pre-lubricated from the factory with either moly or graphite lubricants depending on the intended use. Ensure lube is present on these surfaces and apply additional lube (PN: MP390331) as needed. Similar lubricants may be used on the jackbolt tips and hardened washer during installation.

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Engineering Data

Torque Nut Helpful Hints

Prior to Tightening:

1. Threads: Check all threads of the main stud to verify that the torque nut will spin on freely prior to installation. If a restriction is found, use a lapping compound on the main threads or chase the threads in either the torque nut or the main stud using a good die or tap. THE

UNRESTRICTED MOVEMENT OF THE torque nut ON THE MAIN STUD IS CRITICAL

IN THE INSTALLATION PROCESS.

2. Spacers: The torque nut should be positioned at the end of the main stud when installation is complete in order to minimize exposed threads which could be damaged. This will also serve to minimize any difficulty in reaching the jackbolts and avoid the need for thinwall, or deepwell sockets. A spacer or stacked washers can be used beneath the hardened washer to accomplish this. The spacer will also allow a step-over of a damaged area on stud from repeated installations. 3. Gaps: Back off the torque nut to provide a gap of 1/16 to 1/8 inch between the torque nut and the hardened washer prior to beginning the torque application process. This will allow additional jackbolt extension which provides easy access for jackbolt tip lubrication prior to removal. When closing a gap between flanges, or where long fasteners are used, there may be insufficient jackbolt stroke to allow this step. 4. Sockets: Use only six-point quality sockets in good condition. Worn sockets will eventually round out the corners of the jackbolts possibly causing damage or injury.

While Tightening:

5. Do not tighten a jackbolt completely prior to moving on to the next jackbolt. As the torque nut is tightened, the first jackbolt that was tightened in that sequence will have a tendency to loosen. It will be faster to make multiple passes by moving quickly between jackbolts. 6. Overshoot the Target Torque as indicated PRIOR to the final tightening. This will quicken the tightening sequence by stabilizing previously tightened jackbolts sooner. BE CERTAIN

NOT TO “STABILIZE” THE JACKBOLTS AT THIS HIGHER TORQUE VALUE!

While Removing:

7. Removing the jackbolts too quickly during disassembly may increase the removal torque of the remaining jackbolts. If a jackbolt should become jammed, re-tighten several jackbolts to either side to even the tension on the torque nut. 8. If a jackbolt tip “mushrooms” its tip must be cut off with a cutoff wheel or abrasive disc, then the jackbolt removed.

Engineering Data

Locking Assemblies

To install a locking assembly:

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1. Clean and lightly oil all parts of the locking assembly, the shaft or pin and the housing bores. Be sure the bores to be connected are properly aligned. 2. Loosen all socket head capscrews on the locking assembly. 3. Install the locking assembly and the shaft or pin into the housing. Carefully note any measurements required to align the locking assembly.

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Engineering Data

4. Tighten the capscrews of the locking assembly evenly. Do not tighten each screw all at once. Instead, gradually tighten each one and proceed with the entire set, using a crisscross pattern, and repeat until all screws are tight. Refer to the proper section of the maintenance manual for the specific torque required.

Where pilot bushings are used:

1. Insert the locking assembly as stated above - except remove all socket head capscrews.

2. Insert 3 pilot bushings, equally spaced. Insert the longer capscrews supplied with the pilot bushings. 3. Tighten the capscrews using the same procedure required for the locking assembly capscrews. 4. Once the pilot bushing is has been properly tightened, remove the longer socket head capscrews and the pilot bushings. Replace the capscrews in the locking assembly with the socket head capscrews that came with the locking assembly. 5. Tighten all capscrews using the procedure above. Retain the pilot bushings and longer capscrews for future use.

Engineering Data

Locking Assembly Removal

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For series 1015 assemblies with a center collar:

1. Loosen all capscrews on the locking assembly by at least 2 turns in 1/4 turn increments. 2. Transfer all the capscrews to the push-off threads provided in the clamp collar and in the center collar.

3. Progressively tighten all screws in a diametrical pattern - except the screws adjacent to the slit in the clamp collar - these should be tightened one after the other.

For series 4000 assemblies with NO center collar:

1. Loosen all capscrews on the locking assembly by at least 2 turns in 1/4 turn increments. 2. The locking assembly incorporates a self-releasing taper, which should allow the assembly to be removed. However if the thrust rings jam, tap on the heads of 3 equally spaced capscrews to positively release the connection. 3. Insert pullout screws in the threads under the cadmium plated locking screws to remove the assembly.

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Pinion And Hub Installation

Removal From A Shaft

Engineering Data

A properly mounted pinion, brake drum or coupling will have an interference fit with the shaft causing it to release suddenly and violently when broken loose. Loosen the shaft nut just enough to allow the pinion, brake drum or coupling to free itself. The shaft nut will stop the pinion or coupling and avoid injury to personnel.

NOTE: When removing the pinion, brake drum or coupling from a motor shaft, always use a suitable puller to avoid causing damage to either the pinion, coupling, motor frame, bearings or shaft. Do not heat the pinion, brake drum or coupling before pulling and do not use wedges between them and the bearing cap. To prevent damage to the antifriction bearings, avoid the use of a sledge hammer on the puller.

Mounting A Pinion Or Hub On A Shaft

Successful operation of the gearing largely depends on the proper mounting of the pinion, brake drum or coupling on the shaft.

NOTE: Mounting pinions, brake drums or coupling by heating them in boiling water and driving them on the shaft with a blow from a heavy sledge hammer is not recommended. This results in uncontrolled advance of the pinion or coupling on the shaft. Too great an advance can cause breakage of the pinion, brake drum or coupling core, while insufficient advance can cause slippage and wear in spite of the presence of the key. In addition, hammer blows can injure the finished surface of the anti-friction bearings.

Pinions, brake drums or couplings must be mounted to a definite advance on the shaft, without hammer blows. This requires heating them to a higher temperature than is obtainable with boiling water, and is based on a difference in temperature between them and the shaft. The following is the recommended method for mounting pinions, brake drums or couplings:

1. Thoroughly clean the pinion, brake drum or coupling seating surface on the shaft and the bore of the pinion, brake drum or couplings. Use toluol or percholoethylene; do not use kerosene.

Solvents may be toxic or flammable. Adequate ventilation must be provided to minimize fire and health hazards. Use away from sparks, heat or flame to prevent fire or explosion. Follow the manufacturer’s instructions.

Engineering Data

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2. Remove any scoring from either part. Spot the cold pinion, brake drum or coupling on the shaft by hand to obtain at least a 75% fit. Check the fit with bluing. Remove the pinion, brake drum or coupling. 3. Break all sharp edges of the key and the keyway with a fine file, so there will be a radius of about 1/64 inch at each edge. Fit the key to the shaft, taking care to avoid upsetting the metal of the shaft adjacent to the key. If previously upset, file lightly, checking the fit with bluing until a 75% fit results. Try the pinion, brake drum or coupling on the shaft to make certain it does not bind on the key. 4. Mount the pinion, brake drum or coupling cold by placing it on the shaft and snapping it into position by hand. Measure the “cold” position of the pinion, brake drum or coupling using a micrometer depth gauge. Mark the places where the depth gauge was resting so measurements can be made from the same position after the pinion, brake drum or coupling has been mounted. The following figure illustrates the method of using the depth gauge.

5. Remove the pinion, brake drum or coupling from the shaft and heat it in a suitable oven to the temperature specified. If the pinion, brake drum or coupling is heated in oil, the bore must be thoroughly cleaned before mounting. To avoid the cleaning, the use of an oven is recommended.

Use suitable protective equipment when handling hot items.

The pinion, brake drum or coupling temperature is indicated as a temperature difference between the shaft and pinion; this temperature difference is estimated only and can be adjusted to maintain the specified advance. Heat the pinion, brake drum or coupling in the oven until the temperature is uniform at the required number of degrees above the shaft temperature. For example, if the shaft temperature is 25oC (77oF) and the estimated difference is 125oC (225oF), heat the pinion, brake drum or coupling to 150oC (320oF) for mounting.

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Engineering Data

Pinion, brake drum or coupling temperature must never exceed 190oC (374oF).

Some accurate method must be provided for quickly measuring the temperatures of the pinion, brake drum or coupling and shaft before mounting them. This is best done with a hand pyrometer (refer to the figure). When a hand pyrometer is not available, a centigrade thermometer can be used by placing putty over the bulb to hold it against the pinion or coupling. Heat the pinion, brake drum or coupling a few degrees above the desired temperature before removing it from the oven. Wait until it has cooled to the temperature desired, remove the thermometer and quickly mount the pinion, brake drum or coupling as described below.

6. After making sure the bore is clean, quickly mount the hot pinion, brake drum or coupling on the shaft. When it is nearly engaged with the taper fit (but not actually in contact), snap it forcible into place with a quick push. It is important that the hot pinion, brake drum or coupling be instantly snapped into position before it has cooled appreciably; otherwise it will immediately “freeze” to the shaft and cannot be adjusted further. 7. Check the “hot” or shrunk-on position of the pinion, brake drum or coupling on the shaft, using the micrometer depth gauge. The actual advance is the difference between depth gauge readings at the hot and cold positions. To control the stresses in the pinion, brake drum or coupling, the advance must be within the limits specified in the table below. If the advance is not within the limits given, the pinion, brake drum or coupling should be pulled and remounted. 8. Assemble the lockwasher and nut, tighten firmly and lock. Where a lockwasher is not used, retaining compound must be used to keep the nut tight during operation.

When a lockwasher is used, the nut must be firmly tightened against it, then the tab on the lockwasher must be bent against the flat of the nut. This is required to keep the nut tight during operation.

Engineering Data

Hub Adapter Pre-heat Advance Requirements

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Motor Coupling Pre-heat Advance Requirements

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Engineering Data

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Maintenance Welding

These recommendations for repair welding apply to the major structural members of the machine. The high cyclic loading characteristics of the machine are considered in the design and material selected for the construction of the machine. However, due to unusual operational conditions that may be encountered and to the great number of cyclic loadings that may be applied to the machine, fatigue cracks or other abnormalities may occur. Early detection of these conditions through regular machine inspection helps to avoid problems or emergency breakdowns.

Maintenance welding is applied to the repair of cracked or broken structural components. Reconditioning of broken parts by the application of heating, cutting and welding processes requires attention to a number of details, careful adherence to the repair procedure and observance of federal, state and local safety regulations.

WELDING AND THERMAL-CUTTING OF METALS INVOLVE THE GENERATION OF TEMPERATURES UP TO THOUSANDS OF DEGREES AT WHICH METALS MELT AND VAPORIZE. When proper precautions are taken to protect personnel and property against the heat, evolved gases and fumes, electric shock and radiation, no harm will result either to personnel or property. In gas heating and cutting, the handling and storage of compressed gases present other hazards that also must be protected against to provide a safe working environment.

Safety precautions should conform to the latest edition of ANSI standard Z49.1, Safety in Welding and Cutting, published by the American Welding Society.

Reconditioning of failed members requires attention to a number of details and careful application of the repair procedure. Only in certain cases is it necessary to strengthen members by added reinforcement.

REINFORCING STRUCTURAL MEMBERS SHOULD BE MADE ONLY UPON RECOMMENDATION BY THE MANUFACTURER. IMPROPERLY APPLIED REINFORCEMENTS CAN HAVE AN ADVERSE EFFECT ON THE PERFORMANCE AND LIFE OF THE STRUCTURE.

A broken member is best repaired by making a complete penetration weld, preferably by welding from both sides, using the correct welding electrode and observing all precautions such as preheat, back-gouging, etc. The complete penetration groove weld should be ground flush with the base metal on both sides to remove all surface irregularities. An alternate procedure incorporates backup bars to ensure sound, complete penetration welds in the repair area. Be sure to follow all applicable safety measures and federal, state and local regulations.

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Engineering Data

A complete penetration weld repair conditioned by grinding instead of adding reinforcement is favored to maintain the original pattern of stress flow designed into the structural members. Addition of reinforcement which is not part of the design can reduce fatigue strength because of the change in geometry from the original structure.

Effective repair welding of cracked, broken or bent structural members of the machine involves knowledge of the types of steel used, proper welding electrodes and recognized good welding practice. The chemical composition, mechanical properties and thickness of the steel determine the welding electrode to be used and the preheat temperature required.

Welding Electrodes

With the exception of the boom, weld repairs on the various structures of the machine can be made with two basic classifications of shielded metal arc electrodes: E7018 and E8018-C1. Both are low hydrogen electrodes which deposit weld metal having excellent properties at strength levels with 70,000 to 80,000 PSI, and impact properties from -20o to -75oF. These are all-position electrodes which produce high quality welds for repairing the structural components of heavy machinery.

NOTE: Although these electrodes are of superior quality, care must be exercised in their application. Low hydrogen electrodes are highly susceptible to moisture pickup after removal from sealed containers. To maintain low hydrogen, crack-resistant properties, they must be stored in electrode ovens at 250oF up to the time of use. Small portable rod ovens at the welder’s side are ideal. Use of dry low hydrogen electrodes cannot be over-emphasized.

Cracks caused by hydrogen are extremely fine and occur invisibly below the surface in the base metal heat affected zone, as shown. Therefore, they are not detectable at the time of welding.