Kawasaki WHEEL LOADER 90ZIV-2 CUMMINS M11-C Engine SHOP MANUAL AAA-S90C3V01-012 (1)

AAA-S90C3V01-012 (93213-00081)

WHEEL LOADER SHOP MANUAL

90 Z

Powered by CUMMINS M11-C Engine.

SERIAL NUMBERS 90C3-5501 and up.

Troubleshooting Measurement for Performance Check

FOREWORD To ensure good machine performance, reduce failures or problems, and prolong the service life of each component, it is necessary to operate the machine as is directed in the Operator and Maintenance Manual.

To effectively diagnose and repair the machine, it is important to follow the guidelines laid out in this Shop Manual.

Troubleshooting Measurement for Performance Check Note: ① For General Information and Functions and structure, refer to the 90ZⅣ -2 Shop Manual AAA-S90C3V00-012 (93213-00071). ② For Disassembly and reassembly and Service standard, refer to the 90ZⅣ -2 Shop Manual AAA-S90C3V14-012 (93213-00091) ③ For the engine, refer to the engine Shop Manual provided by the engine manufacturer.

The purpose of this manual is to provide information on the product and the correct maintenance and repair methods.

Please read this manual to ensure correct troubleshooting and good repair service.

This manual will be periodically reviewed and revised for more satisfactory content. If you have any opinions or requests, please inform us.

（1）

Safety Precautions The most important point in providing repair service is safety. To ensure safety, observe the general cautions described below.

・ This manual is intended for properly trained and equipped service technicians. ・ Any work on the machine must be performed by the trained personnel only. ・ Carefully read this manual to thoroughly understand the operation method before you operate or repair the machine. ・ Be sure to wear appropriate clothes and protectors, such as safety boots, hard hat and goggles. ・ Place the machine on a level and solid ground, and place chocks against the wheels to prevent movement. ・ Remove the cable from the battery before starting the service work, and attach a "DO NOT OPERATE!" tag to the steering wheel. ・ Be sure to release the internal pressure before you remove a pipe, such as the hydraulic oil, air, or engine coolant pipe. ・ Be sure to apply the articulation stopper before starting work. ・ While supporting the bottom of the chassis using a jack, be sure to support the chassis using the blocks. ・ When the boom or bucket is raised or when a unit is lifted by a crane, be sure to place a stand or adequate cribbing under the unit to prevent unexpected dropping. ・ Do not start to work in an enclosed area if adequate ventilation is not provided. ・ To remove a heavy unit (20kg (40 lbs) or more), be sure to use a crane or other lifting tool. ・ Just after stopping operation, be careful not to directly touch a hot component. You may get burned. ・ Contact tire manufacturer's local dealer for tire servicing and changing. ・ Always store the tools in good condition, and use them properly. ・ Keep the work area clean. Clean up spills immediately. ・ Avoid the use of flammable solvents and cleaners. ・ When working outdoors keep work areas, ladders, steps, decks and work platforms clear of snow, ice, and mud. ・ Use safe work platforms to reach higher areas of the machine.

（2）

Safety Symbols An accident may occur if you disregard safety rules.

In this manual, several expressions are used according to levels of danger for inspection and repair work as shown below. Read the work procedures and cautions described in this manual, and take preventive measures against possible problems before starting service work.

DANGER This danger symbol identifies special warnings or procedures which, if not strictly observed, will result in death or serious injury.

WARNING This warning symbol identifies special warnings or procedures which, if not strictly observed, could result in death or serious injury.

CAUTION This caution symbol identifies special instructions or procedures which, if not strictly observed, may result in minor or moderate injury.

IMPORTANT This important symbol identifies special instructions or procedures which, if not correctly followed, may result in serious machine damage.

We cannot predict all possible accidents or incidents that may occur during service work. Therefore, an accident that is not specifically mentioned in this manual may occur. To protect yourself from all accidents, be careful when doing service work.

（3）

Symbols For safe and effective service work, the following symbols are used for notes and useful information in this manual.

Symbol

Item Reference

Description Shows the condition or procedure that will be useful or efficient in doing service work.

Shows the weight of a part or unit. The weight

Weight

should be considered in selecting wire rope or cable for slinging work or determining the working posture.

Shows the tightening torque of a section that Tightening should be carefully tightened during assembly torque work.

Coating

l

Oil or water supply

Drainage

Shows the type of coating or adhesive and the coating section.

Shows the oil or water supply port and the refill amount.

Shows the oil or water drain port and the drain amount.

IMPORTANT If the specified conditions are not satisfied or the specified procedure is not observed, there is a strong possibility that the product will be damaged or the performance of the product will be reduced.

The message shows the preventive measures.

（4）

Troubleshooting ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-1 Measurement for performance check ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 03-1

Troubleshooting 01 Cautions Regarding Troubleshooting ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-3 How to Use Quick Troubleshooting Table ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-4 Safety Precautions ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-5 Quick Troubleshooting Table Torque Converter and Transmission Group 1.

Machine does not move in any shift lever position ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-6

2.

Machine does not move at a certain shift lever position ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-7 (or: Machine moves only in a certain shift lever position)

3.

Machine moves at the neutral position ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-8 (Example: Machine moves forward at the neutral position)

4.

Large shock at starting or changing speeds / direction ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-9

5.

Large time lag at starting or changing speed / direction ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-10

6.

Low power ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-11 (Defective torque converter or transmission)

7.

Torque converter oil is overheating ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-12

8.

Machine moves reverse when starting to climb up on a slope using inching brake ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-13

9.

Automatic speed change is not possible ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-14

10.

QUAD switch does not work ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-15

Hydraulic Group 1.

Boom and/or bucket do not move ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-16

2.

Boom and/or bucket have low power, or move too slowly ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-17

3.

Excessive cylinder drift ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-19

4.

Boom and/or bucket are spongy ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-21 (Holding bucket against the ground is not possible)

5.

Bucket positioner (kick-out) does not work ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-22

6.

Steering is not possible or hard to steer ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-23

7.

Machine sways, or a shock during steering ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-24

8.

Abnormal noise in hydraulic system ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-25

9.

Others ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-26

01-1

Brake Group 1.

Brake does not work well (In the worst case, the brake does not work at all) ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-27

2.

Brake is dragging when released ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-28

3.

Brake oil level lowers too much ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-29

4.

Stepping on the brake pedal sounds the buzzer ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-30

5.

Air pressure does not rise, or too slow in rising ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-31 (Pressure indicated on the pressure gauge is too low)

6.

Parking brake does not work ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-32 (or: Releasing the brake is not possible)

Electrical Group 1.

Engine hard to start or will not start ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-33

2.

Engine will not stop even if the starter switch is turned to "OFF" (or: Starting the engine is not possible) ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-34

3.

Instrument panel does not indicate properly ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-35

4.

Breaker of the transmission controller is turned off ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 01-36

01-2

Cautions Regarding Troubleshooting ・ Important points

The

following

questions

will

be

helpful

in

The important points for troubleshooting is to

determining of the cause. Answer the questions to

carefully read the operation manual and shop

prevent an incorrect diagnosis.

manual to get enough information on the operation,

1. Did the problem occur suddenly?

circuits, structure, and function of each component.

2. When did the operator notice the problem?

If you have enough knowledge of each component

3. Is there any past problem that may be the cause

and system, you can easily determine the cause of

of this problem?

the problem.

4. When the problem occurred, what kind of work

There may be various causes for each problem,

was the operator doing?

therefore experience will be needed to determine

5. Has the machine had the same kind of problem

which is the actual cause of the problem.

before?

It is necessary to know the normal operation of

6. Has the machine been repaired or inspected

each component. In addition, it is also important to

recently?

know the abnormal condition when a problem

7. Does the machine have any other problem?

occurs. This chapter shows various examples of past problems, and describes possible causes and

・ Troubleshooting

remedies for each problem.

・ Check before determination of cause A

・ Before starting troubleshooting

problem

may

be

caused

by

poor

daily

maintenance, such as lack of grease, low or

To prevent incorrect diagnosis, talk with the

improper oil or a clogged filter. Be sure to check

persons concerned, particularly with the operator,

the machine for oil level, appearance, unpleasant

to get enough information on the problem.

odor, etc. to prevent time loss due to other

If

unnecessary tests.

possible, check the machine by repeating the

・ Inspection procedure

symptom.

If the problem cannot be repeated, do not provide

As a rule, check the easy-to-be-repaired system

any repair service.

first (excluding the cases where the cause can be

For instance, assume that the operator complains

easily determined based on the past experiences).

that the boom power is low, and the rim-pull is also

This machine is controlled by electrical, hydraulic,

low. In this case, there are two possible causes;

and mechanical systems.

low hydraulic power and low rim-pull.

The

be-repaired system is the electrical system. Check

remedies against both causes are much different

the electrical system first. If no problem is detected

from each other.

in the electrical system, check the hydraulic

If you hastily determine the wrong cause without

system, and then the mechanical system.

checking the actual condition of the problem, it will take too much time and expense to solve the problem. As a result, you will not be trusted by the user.

01-3

The most easy-to-

How to Use Quick Troubleshooting Table To immediately determine the cause of the problem without

disassembling

parts,

use

the

quick

troubleshooting table. From the problem explained by the user and the check points written in the table, you can immediately determine the cause of the problem.

・ How to use quick troubleshooting table

(4) Generally, the possible cause that has many

(1) According to the problem explained by the user,

check marks will be the actual cause. If two or

open the quick troubleshooting table to the page

more possible causes have several check marks,

where the corresponding problem is described.

check each possible cause to prevent an

(2) Check

the

machine

according

to

the

incorrect diagnosis.

"Symptoms/check point" field in the table. Start

In this case, start from the most easily checked

from the most easily checked point.

item.

(3) Operate the machine, and write the check marks "

" in the corresponding circles " ○ " if the

problem occurs.

01-4

Safety Precautions WARNING

WARNING

Unexpected operation of the machine may cause an accident resulting in injury or death.

Therefore, to provide repair service during engine running, be sure to observe the following items: ・Park the machine on level ground. ・Apply the parking brake. ・Brace the tires with chocks to prevent accidental movement. ・Determine the signals between the service technicians. ・Prohibit any person from entering into dangerous areas. ・ Near articulation area of the machine ・ Under the machine ・ Around the engine ・ In front of or behind the machine

Do not enter the articulation area of the machine if the engine is operating. An accident resulting in injury or death may occur.

To enter the articulation area, be sure to stop the engine, and remove the starter key. In addition, hang a "DO NOT START THE ENGINE!" tag on the steering wheel.

WARNING Unexpected operation of the machine may cause an accident resulting in injury or death.

To crawl under the machine, be sure to stop the engine, and brace the tires with the chocks to prevent them from rotation. Give signals to the person in the cab during the work.

WARNING CAUTION

Standing under the boom or bucket during service work is dangerous. An accident resulting in injury or death may be caused.

To prevent such an accident: ・Lock the boom and bucket control levers in the cab. ・Remove the starter key. ・Hang a "DO NOT OPERATE!" tag on the steering wheel. ・Securely brace the boom / attachment in the raised position.

Do not touch the fan or V-belt of the engine or a high-temperature section if the engine is running.

An accident resulting in injury may occur.

Be sure to stop the engine before you open the side cover of the engine room.

Avoid high temperature components even when the engine is stopped.

CAUTION Be careful, injury may occur if high pressure oil sprays out. To prevent such an accident, before removing the plug from the pressure measurement port, be sure to: ・Release the residual pressure from the pipe. ・Open the cap of the hydraulic oil tank.

01-5

90Z Ⅳ -2

Machine does not move in any shift lever position

QUICK TROUBLESHOOTING TABLE 01

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ

Pump produces an abnormal(shrieking)noise

[opt.].)

Controller LED "I" indicator is on

will operate except horn circuit and hazard flasher

Filter of the torque converter is clogged

(If the 70A fusible link is off, no electrical circuits

Temperature of the torque converter oil is too high

on.

(5) Check the 70A fusible link.

Torque converter oil becomes milky and cloudy in color

(4) Check that the circuit protector of the controller is

Low clutch oil pressure at all the shift lever positions

(3) Check the fuse of the controller system.

Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

(2) Check the torque converter oil level.

Pump is extremely heated

(1) Check that the parking brake is released.

Even if the breaker of the controller is turned ON, the breaker will be immediately turned off

Check before starting work

The controller LED "X" indicator is OFF

1. Machine does not move in any shift lever position

Setting the T/M(transmission)cut-off switch to OFF allows normal operation

Torque Converter and Transmission Group

Ｓ ｏ ｌ ｕ ｔｉｏ ｎ

Air drawn into suction line of the torque converter pump

○ ○ ○

○ ○

Tightening hose band

Defective torque converter pump

○

○

Pump replacement

○ ○ ○

Damaged torque converter Sticking clutch pressure regulator valve

○

Malfunctioning trimmer solenoid valve

○

Disassembly&repair Disassembly&repair Disassembly&repair

○ ○

Malfunctioning inching switch

Switch replacement

○

Defective controller

Controller replacement

○

Short circuited clutch solenoid valve or wiring Restricted suction line-pinched, plugged, or internally defective

Repairing cable

○ ○

01-6

Replace hose

Machine does not move at a certain shift lever position

90Z Ⅳ -2

QUICK TROUBLESHOOTING TABLE 01

Clutch slipping

○

Machine may move even when shift lever is in "NEUTRAL"

Controller IN and OUT LED do not correspond with each other, controller failure light on dash is ON

Controller input LED will not light at a certain shift lever position

Breaker of the controller will be turned off at a certain shift lever position

Disassembly

○ &repair

Disassembly &repair

○

○

Coil of clutch solenoid valve is defective

○

Harness of clutch solenoid valve disconnected

○

○ ○

Clutch solenoid valve sticking in OFF position

○

○

○

Solenoid valve replacement

○

○

Repair cable Solenoid valve replacement Solenoid valve replacement

○

Shift lever replacement

○ ○

Shift lever switch sticking in ON (regardless of position) ○

○

○ ○

***

○

Solenoid valve replacement

○

Defective controller ** Refer to "operation error preventive function". *** If "F" or "R" switch is stuck in the "ON" position.

01-7

Shift lever

○ replacement ○

Damaged clutch solenoid valve diode

＊ Ｒｅｍａｒｋｓ

At a certain shift lever position, the controller input LED is turned on and will not go out

○

Clutch oil leaks internally

Clutch solenoid valve sticking in ON position

Ｓｏｌｕｔ ｉｏｎ Disassembly &repair

○ ○

Seized clutch

Shift lever switch sticking in OFF (regardless of position)

Clutch oil pressure is always high despite shift lever position and output LED

Check the possible cause referring to the Section 03 and 62.

Resistance of the solenoid valve coil is too high (more than 26 Ω )

24V power is not supplied to the solenoid valve (output LED OK)

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ

Clutch oil pressure is low at a certain position only. At all the other positions, the pressure is normal

Machine may move unexpectedly during testing causing injury or death. ・ Block the machine securely. ・ Always stay clear of the articulation area and wheels when the engine is running.

Torque converter oil looks and smells as if it was scorched (black)

WARNING

Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

lever position)

Machine moves at a certain shift lever position, but hesitates to move at any other positions

(OR : Machine moves only in a certain shift

Machine does not move at a certain shift lever position, but moves at all the other positions

2. Machine does not move at a certain shift lever position

Clutch can be engaged at a certain shift lever position, though the clutch will not be engaged at any other position**

Torque Converter and Transmission Group

Controller replacement

90Z Ⅳ -2

Machine moves at the neutral position

QUICK TROUBLESHOOTING TABLE 01

Seized clutch on forward side *

○

○

Malfunctioning forward solenoid valve (sticking at ON position)*

○

○

○

Ｓ ｏ ｌ ｕ ｔｉｏ ｎ T/M disassembly and repair

○

Solenoid valve replacement

○

Defective controller(malfunctioned after outputting "F")* Defective shift lever(switch stuck in "F" position)*

Controller output LED "F" will go out when shifted to reverse (output LED "R" will not turn on). Machine feels like its neutral.

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ

Controller input LED "F" indicator is on and will not go out

Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

(1) Check that the ground is level

Oil is black and smells scorched

Check before starting work

Controller output LED "F" indicator is on and will not go out

neutral position)

When the lever is shifted to the reverse position, the machine does not move reverse (as if the brake is applied)

3. Machine moves at the neutral position (Example: Machine moves forward at the

When the lever is shifted to the forward position, the machine moves forward

Torque Converter and Transmission Group

○ ○

Controller replacement

○

Shift lever replacement

＊ Ｒｅｍａｒｋｓ

* The same possible cause but involving the reverse clutch or circuit could occur with the opposite symptoms.

01-8

Large shock at starting or changing speeds / direction

90Z Ⅳ -2

QUICK TROUBLESHOOTING TABLE 01

Circuit protector for T/M controller trips frequently (at each gear change)

Resistance of the trimmer coil is normal (26 Ω )

Resistance of the trimmer coil is O Ω or infinite Ω

Foreign material is on the line filter

Temperature of the torque converter oil is too high

Controller output LED "DC" indicator does not light properly

Main oil pressure rises too quickly at all the shift lever positions

Large shock at a certain shift lever position only

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ

Large shock at all the shift lever positions

Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

4. Large shock at starting or changing speeds / direction

Pressing the trimmer solenoid valve with your finger will cause the main pressure to drop *

Torque Converter and Transmission Group

Ｓ ｏ ｌ ｕ ｔｉｏ ｎ

Malfunctioning control valve or regulator valve operation

○

○

Disassembly&repair

Malfunctioning control valve or trimmer plug

○

○

Disassembly&repair

Malfunctioning trimmer solenoid valve (defective coil etc.)

○

○

Defective trimmer circuit of controller

○

○

○

○

○

Trimmer solenoid valve wiring is disconnected, improperly ○ connected, or defective

○

○

T/M disassembly and repair Disassemble, clean, or replace

○

＊ Ｒｅｍａｒｋｓ

* In some cases, due to seizing or contamination, the solenoid valve spool may not move by pressing.

01-9

Solenoid valve replacement Controller replacement

○ ○

○

Trimmer solenoid valve is sticking (closed)

○

○

○

Damaged or worn clutch disk

○

Reconnect or repair wires

Large time lag at starting or changing speed / direction

90Z Ⅳ -2

QUICK TROUBLESHOOTING TABLE 01

Charge pump extremely heated

Abnormal noise from charge pump (shrieking)

Torque converter oil overheats

Time lag just after using the inching brake

Large time lag at a certain shift lever position only

Main oil pressure is too low at all the shift lever positions

Controller output LED "D" indicator does not light properly or stays ON

Main oil pressure rises too slowly at all the shift lever positions

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ

Large time lag at all the shift lever positions

Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

5. Large time lag at starting or changing speed / direction

Clutch oil pressure is too low or rises too slowly at a certain shift lever position only

Torque Converter and Transmission Group

○

Ｓ ｏ ｌ ｕ ｔｉｏ ｎ

Defective torque converter pump

○ ○

Malfunctioning control valve or regulator valve

○ ○

Disassembly&repair

Malfunctioning control valve, trimmer plug, plugged orifice ○ ○

Disassembly&repair

Disassembly&repair

Broken or non-resilient control valve spring

○ ○

○

Spring replacement

Malfunctioning trimmer solenoid valve spool (sticking open)

○ ○

○

Disassembly&repair

Defective trimmer circuit of controller

○ ○ ○ ○

Internally leaked clutch oil

T/M disassembly and repair

○ ○

Malfunctioning inching pressure switch Restricted suction line-pinched, internally defective

Controller replacement

○ ○

01-10

Switch replacement

○ ○ ○

Replace hose

90Z Ⅳ -2

Low power

QUICK TROUBLESHOOTING TABLE 01

Torque Converter and Transmission Group 6. Low power (Defective torque converter or

Air drawn into suction line of torque converter

○

Broken torque converter turbine and pump

○

Torque converter internal pressure too low

○

○

Pump produces an abnormal(shrieking)noise

○ ○

Iron and/or fiber material in line filter and strainer

Pump is extremely heated

Clutch oil pressure is too low at a certain shift lever position

○

Ｓ ｏ ｌ ｕ ｔｉｏ ｎ Tightening suction hose band T/M disassembly and repair

○

Regulator valve check

Seized clutch

○ ○

○ ○

Clutch slipping

○

○

Internally leaking clutch oil

○

Restricted suction line-pinched, internally defective

Silver powder (Aluminum) is on the line filter and strainer

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ

Torque converter oil is milky and cloudy in color

link of the engine governor operates at full stroke.

Temperature of the torque converter oil is too high

hydraulic line(like excessive pilot pressure).

(4) Step on the accelerator pedal, and check that the

Torque converter oil is discolored or emits nasty smell

(3) Check that no unusual load is applied to the

Output power is low at a certain shift lever position only

(2) Check the torque converter oil level.

Output power is low at all the shift lever positions

dragging.

Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

(1) Check the parking brake and foot brake for

Large time lag at a certain shift lever position only

Check before starting work

Machine moves even if the shift lever is set to the neutral position*

transmission)

○

＊ Ｒｅｍａｒｋｓ

* If the seized clutch is Forward or Reverse clutch.

01-11

○

T/M disassembly and

○ repair

T/M disassembly and repair T/M disassembly and repair

○ ○

○ ○

Replace hose

90Z Ⅳ -2

Torque converter oil is overheating

QUICK TROUBLESHOOTING TABLE 01

Torque Converter and Transmission Group

Air drawn into suction line of torque converter Internally torque converter leakage

Engine RPM at no load or during stall test is too low

Installing thermometer in T / C out line indicates less then 250 °F / 120 ℃ when gauge or light indicates overheat

One or more planetaries are hotter than others

Parking brake is excessively hot / discolored

T/C disassembly and repair

○ ○

T/C disassembly and repair

○

T/M disassembly and repair

○ ○

T/M disassembly and repair

○ ○ ○

T/C disassembly and repair

○ ○ ○

Clutch slipping

○

Scale deposited in water line of torque converter cooler ○ ○

Cooler cleaning

○ ○ ○

Wrong oil viscosity is used

Ｓｏｌｕｔ ｉｏｎ Tightening hose band

○

Seized clutch

Restricted suction line-pinched, internally defective

Less difference in torque converter oil temperature between cooler inlet and outlet

Pump produces an abnormal(shrieking)noise

Pump is extremely heated

○

Damaged torque converter Torque converter pump discharge amount too small

Output power is too small at a certain shift lever position

Torque converter inlet pressure is too low

Clutch oil pressure is too low

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ

Torque converter oil is milky and cloudy in color

(3) Check tire pressures-adjust to specification.

Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

Oil level too high.

(2) Check the engine coolant for overheat.

Torque converter oil is discolored or emits nasty smell

(1) Check the torque converter oil level.

Foreign material is on the filter-especially silver powder (Aluminum)

Check before starting work

Machine does not move at a certain shift lever position (or dragging is felt)

7. Torque converter oil is overheating

Replace hose Replace w/proper oil

○

Test/repair brake circuit

○ ○

Service or parking brake dragging Operator is using too high gear for load

Train operator

Incorrect indication of gauge (no alarm) Alarm switch defective (gauge in green zone)

○

Test/replace gauge or sender

○

Replace switch

○

Contamination in oil cooler (oil side)

Replace cooler

○

Engine RPM too low / Engine power too low

01-12

Machine moves reverse when climbing

90Z Ⅳ -2

QUICK TROUBLESHOOTING TABLE 01

Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

8. Machine moves reverse when starting to climb up on a slope using inching brake

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ

After pedal release, too much time is required to turn off the controller LED "I" indicator

Torque Converter and Transmission Group

Large time lag in clutch engagement Delay in resetting inching pressure switch

Ｓ ｏ ｌ ｕ ｔｉｏ ｎ Refer to description of time lag

○

01-13

Switch replacement

90Z Ⅳ -2

Automatic speed change is not possible

QUICK TROUBLESHOOTING TABLE 01

Controller input LED "SPI1" is on

Ｓ ｏ ｌ ｕ ｔｉｏ ｎ Shift lever replacement or repairing wire

○ ○

Sensor replacement or repairing wire

○ ○

○ ○

Sensor replacement or readjustment

○

○

Controller replacement

Damaged speed sensor or disconnected sensor

○

Speed sensor signal output error or improperly adjusted speed sensor Defective controller

○ ○

Low speed(engine output power too low) Parking or service brakes dragging

Actual speed increase or reduction does not correspond with the set speed

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ

Defective shift lever "A" position or defective wiring to controller

Controller LED's "1〜4" do not flicker or light when M/C is moving

lever position."

Controller input LED "D" indicator does not light

refer to "Machine does not move at a certain shift

Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

speed. If manual speed change is impossible,

Speed is properly increased on a downward slope

(1) Manually change the speed from 1st speed to 3rd

Speed is fixed to 3rd speed, and is not increased to 4th speed

Check before starting work

Speed is fixed to 2nd speed, and automatic speed change is not possible

9. Automatic speed change is not possible

One or more planetaries are excessively hot/parking brake is hot or discolored

Torque Converter and Transmission Group

○ ○ ○

Automatic mode by passed by jumper wire at controller "Man/Auto" connector

Inspection&repair

○

Repair brake circuit

○

01-14

Remove jumper wire

QUAD switch does not work

90Z Ⅳ -2

QUICK TROUBLESHOOTING TABLE 01

Check before starting work (1) Check that the QUAD switch is being used only at At other positions, shifting down is not possible.

(2) Check the fuses.

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ

Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

the 2nd forward/reverse speed position.

Controller input LED "SPI2" indicator does not light when the QUAD switch is turned on

10. QUAD switch does not work

Controller input LED "SPI2" indicator lights when the QUAD switch is turned on but output does not change

Torque Converter and Transmission Group

Ｓ ｏ ｌ ｕ ｔｉｏ ｎ

Defective switch

○

Switch replacement

Disconnected switch or wiring

○

Repair wire

○

Defective controller

01-15

Controller replacement

90Z Ⅳ -2

Boom and/or bucket do not move

QUICK TROUBLESHOOTING TABLE 01

Broken pump drive shaft

○

Internally damaged steering pump

○

○

Internally damaged main pump

○

○

Internally damaged pilot pump

○ ○

○

Oil leakage from overload relief valve

○

○

Multiple control valve plunger sticking

Pump is extremely heated

Disassembly

○ &repair ○

○

Disassembly &readjustment Disassembly &readjustment

○ ○

○

○

Main relief valve produces a noise

Cylinder does not operate, though oil is discharged from the return port

○ &repair

Plunger replacement Disassembly &readjustment

○ ○ ○

Bucket moves if the overload relief valves are exchanged with each other *

After warm-up, it is possible to operate the bucket and boom

Pilot relief pressure is too low

No pilot relief pressure built

Disassembly

○

○

Defective pilot relief valve Internally damaged cylinder

Disassembly

○ &repair

○ ○

Oil leakage from main relief valve

Ｓｏｌｕｔ ｉｏｎ Pump replacement

○

○ ○

Multiple control valve

Pump

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ

Either the boom or bucket does not move

(3) Check that the pilot valve filter is not clogged.

Steering is not possible either

released.

Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

(2) Check that the loading control lock lever is fully

Main relief pressure is too low when the boom or bucket is operating

(1) Check the oil level.

Boom and bucket move with no load, though they do not move when loaded

Check before starting work

No main relief pressure built

1. Boom and/or bucket do not move

Boom and bucket do not move normally while the engine runs idle but appears to move normally while it runs at full speed

Hydraulic Group

○

Disassembly &repair

* Remarks

* Exchange of the overload relief valve means that the valves should be changed between the rod and bottom sides.

01-16

90Z Ⅳ -2

Boom and/or bucket have low power or slow

QUICK TROUBLESHOOTING TABLE 01

If the brakes, service or parking, drag it reduces the power available to hydraulics when the machine is moving.(Static testing will show normal hydraulic power and speed.)

(6) Check that the pilot valve filter is not clogged.

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ

Internally damaged steering pump

○

Internally damaged main pump

○ ○

Oil leakage from main relief valve

○ ○

Oil leakage from overload relief valve for bucket bottom side

○

Internally damaged cylinder

○

Oil leakage from reducing valve of pilot relief valve

○

Ｓｏｌｕｔ ｉｏｎ

○

Disassembly &repair

○

Disassembly &repair Disassembly &readjustment

○ ○

Disassembly &readjustment

○

Disassembly &repair

○ ○

Disassembly &repair

○

Warm up hydraulics Replace oil w/proper oil

Oil is cold, wrong oil viscosity (too thick)

○

○

Suction side air leak-clamp, hose, o-rings

○

○

○

Suction line pinched or internally defective

○

○

○

01-17

Pump makes noise (shrieking)

(5) Check that the machine rolls freely in neutral.

Oil is foamy or milky looking after operation, but normal after stopping engine and letting the oil sit for 1 hour

to hydraulics.

Only bucket operation is abnormal

Dragging/seized clutches reduce power available

Only boom lifting operation is abnormal

lever of the transmission is at the neutral position.

Either the boom and bucket does not operate properly

(4) Check that the machine does not move if the shift

Both the boom and bucket do not operate properly

lever of the engine governor operates at full stroke.

Measure/Adjust High Idle (HI) Speed.

Steering system operates properly

(3) Step on the accelerator pedal, and check that the

Steering system does not operate properly

released.

Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

(2) Check that the loading control lock lever is fully

Bucket drifts down when full

(1) Check the oil level.

Pump is extremely heated

Check before starting work

Main relief valve produces a noise

2. Boom and/or bucket have low power, or move too slowly

Stop the engine when the boom is on its way up(or down). Holding the boom at that position is not possible

Hydraulic Group (S/N 90C3-5501〜5700)

○

Check & repair

○ suction line

Check & repair

○ suction line

90Z Ⅳ -2

Boom and/or bucket have low power or slow

QUICK TROUBLESHOOTING TABLE 01

Check before starting work (1) Check the oil level.

If the brakes, service or parking, drag it reduces the power available to hydraulics when the machine is moving.(Static testing will show normal hydraulic power and speed.)

(6) Check that the pilot valve filter is not clogged.

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ

Internally damaged steering pump

○

Internally damaged main pump

○ ○

Oil leakage from main relief valve

○ ○

Oil leakage from overload relief valve for bucket bottom side

○

Internally damaged cylinder

○

Ｓ ｏ ｌ ｕ ｔｉｏ ｎ

○

Disassembly&repair

○

Disassembly&repair Disassembly &readjustment

○ ○

Disassembly &readjustment

○

○

Disassembly&repair Warm up hydraulics Replace oil w/proper oil

Oil is cold, wrong oil viscosity (too thick)

○

○

Suction side air leak-clamp, hose, o-rings

○

○

○

Suction line pinched or internally defective

○

○

○

01-18

Bucket drifts down when full

(5) Check that the machine rolls freely in neutral.

Pump is extremely heated

to hydraulics.

Only bucket operation is abnormal

Dragging/seized clutches reduce power available

Main relief valve produces a noise

lever of the transmission is at the neutral position.

Either the boom and bucket does not operate properly

(4) Check that the machine does not move if the shift

Both the boom and bucket do not operate properly

lever of the engine governor operates at full stroke.

Measure/Adjust High Idle (HI) Speed.

Steering system operates properly

(3) Step on the accelerator pedal, and check that the

Steering system does not operate properly

released.

Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

(2) Check that the loading control lock lever is fully

Pump makes noise (shrieking)

2. Boom and/or bucket have low power, or move too slowly

Oil is foamy or milky looking after operation, but normal after stopping engine and letting the oil sit for 1 hour

Hydraulic Group (S/N 90C3-5701〜)

○

○

Check & repair suction line

○

Check & repair suction line

90Z Ⅳ -2

Excessive cylinder drift

QUICK TROUBLESHOOTING TABLE 01

Internal boom cylinder piston seal oil leakage Internal bucket cylinder piston seal oil leakage Oil leakage from multiple control valve main spool Oil leakage from multiple control valve overload relief valve

○

○ ○

○

○ ○ ○

＊ Ｒｅｍａｒｋｓ

* These tests must be carefully done or injury could result.

01-19

Seal replacement

Disassembly&repair Disassembly&repair

○

Oil leakage from reducing valve of pilot relief valve

Ｓ ｏ ｌ ｕ ｔｉｏ ｎ Seal replacement

○ ○ ○

Front wheels drift down when the front wheels are lifted off the ground by means of the boom cylinder

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ

Excessive drift of bucket

Trapped oil under pressure can spray out causing injury. ・ Always release tank and trapped cylinder pressure before removing any lines, plugs or components.

Excessive drift of boom

WARNING

Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

instructions on "Measuring Cylinder Drift".

There is a hose that connects the pilot relief valve to the boom cylinder bottom.

Remove the hose from the pilot relief valve, and attach a blank plug to the valve side. Check that the drift is stopped *

The maximum drift rate is measured according to

In the case that the pipe on the cylinder rod side is removed, the compressed oil spouts out from the cylinder *

3. Excessive cylinder drift

In the case that the overload relief valve is switched or replaced, excessive drift stops

Hydraulic Group (S/N 90C3-5501〜5700)

Disassembly&repair

90Z Ⅳ -2

Excessive cylinder drift

QUICK TROUBLESHOOTING TABLE 01

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ

Internal boom cylinder piston seal oil leakage Internal bucket cylinder piston seal oil leakage Oil leakage from multiple control valve main spool Oil leakage from multiple control valve overload relief valve

Excessive drift of bucket

Trapped oil under pressure can spray out causing injury. ・ Always release tank and trapped cylinder pressure before removing any lines, plugs or components.

Excessive drift of boom

WARNING

Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

instructions on "Measuring Cylinder Drift".

○ ○

＊ Ｒｅｍａｒｋｓ

* This test must be carefully done or injury could result.

01-20

○

○

○

○ ○ ○

Front wheels drift down when the front wheels are lifted off the ground by means of the boom cylinder

The maximum drift rate is measured according to

In the case that the pipe on the cylinder rod side is removed, the compressed oil spouts out from the cylinder *

3. Excessive cylinder drift

In the case that the overload relief valve is switched or replaced, excessive drift stops

Hydraulic Group (S/N 90C3-5701〜)

Seal replacement Seal replacement

○ ○

Ｓ ｏ ｌ ｕ ｔｉｏ ｎ

Disassembly&repair Disassembly&repair

90Z Ⅳ -2

The boom or bucket is spongy

QUICK TROUBLESHOOTING TABLE 01

○

○

Disassembly&repair

Oil leakage from make-up valve for bucket rod side

○

○

○

○

Disassembly&repair

○

Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

Make-up valve does not open on bucket rod side

○ ○

Make-up valve opening impossible on boom rod side

Ｓｏｌｕｔｉｏｎ

Disassembly&repair

○

Oil leakage from make-up valve for boom rod side

Boom is spongy just after quick lowering

Overload relief pressure is too low

○

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ

Boom cannot support the lifted front wheels, or the lifted front wheels soon drop

In case that the overload relief valves are switched*, the boom and bucket are strong enough to support the front wheels.

○

possible-front wheels off the ground)

Boom and bucket are strong enough if the engine runs at the full speed while dumping or lowering

Bucket cannot support the lifted front wheels, or the lifted front wheels soon drop

Oil leakage from overload relief valve for bucket rod side

4. Boom and/or bucket are spongy (Holding bucket against the ground is not

Bucket is spongy just after dumping

During digging operation, the bucket tilts back even though the lever is at the neutral position

Hydraulic Group

Disassembly&repair

○ Disassembly&repair

* Regarding check point above, switching the overload relief valves means that the valves should be changed between the

＊ Ｒｅｍａｒｋｓ

rod and bottom sides of the bucket circuit.

01-21

Bucket positioner(kick-out) doesn't work

90Z Ⅳ -2

QUICK TROUBLESHOOTING TABLE 01

switch and detection bar is properly adjusted.

(5mm ± 2[1/8 ″〜1/4 ″]) (3) Check all the connectors of the electrical power line to be sure they are properly connected.

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ

Defective proximity switch

Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

(2) Check that the distance between the proximity

○

○

01-22

Ｓ ｏ ｌ ｕ ｔｉｏ ｎ Proximity switch replacement

○ ○

Broken magnet coil inside pilot valve Disconnected electrical power line

Magnet coil resistance value is indicated as infinity or 0 Ω

(1) Check the fuses.

Remove the connector of the proximity switch, and connect the red and white wires of the connector to each other on the chassis side. Check that the lever is held properly.

Check before starting work

sw. face)

5. Bucket positioner (kick-out) does not work

LED lamp of the proximity switch does not light (key on & metal plate in front of

Hydraulic Group

Magnet replacement Repair

Steering is not possible or hard to steer

90Z Ⅳ -2

QUICK TROUBLESHOOTING TABLE 01

Hydraulic Group

Internally damaged orbitroll

○ ○

Internal damage of steering pump (deteriorated performance)

○ ○ ○

Defective main relief valve

○

○ ○

○

Defective steering cylinder

Boom slow, steering hard both directions, pump heated

Main relief pressure is too low in one direction only

○ &repair

Disassembly &repair Disassembly &repair

○

○ ○

Defective overload relief valve

Disassembly

○

○ ○

Ｓｏｌｕｔ ｉｏｎ Disassembly &repair

○

○

Malfunctioning steering valve or flow control plunger

If the overload relief valves are exchanged*, steering problem switches sides

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ

Pump is extremely heated

filter is in the inlet fitting of orbitrol.)

Overload relief pressure is too low

(5) Check that the pilot valve filter is not clogged. (The

Steering relief pressure is too low

than normal.

Increasing the engine speed enables smooth operation

(4) Measure steering wheel force to see if it is greater

Steering is not possible at both the idling and full speeds

steering system is normal.

Boom is too slow in rising

& heavy loading can prevent steering even when

Steering wheel is too loose

(3) Check operating conditions. Full brake application

Steering wheel does not rotate

properly adjusted.

Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

(2) Check that the stop bolts for the stop valves are

Steering is possible in either the right or left direction

(1) Check the oil level in the hydraulic tank.

Steering relief valve produces a noise

Check before starting work

Steering is not possible (or hard) in both the right and left directions

6. Steering is not possible or hard to steer

○ ○

Disassembly &repair

○

Disassembly &repair

○

Suction line is pinched or internally defective

○ Check &repair

Cold oil / viscosity too thick for weather

○

* Regarding check point above, exchange of the overload relief valve means that the valves should be changed between the left and right sides. The problem will switch sides also (weak steering to the left will, after exchange, become weak steering

＊ Ｒｅｍａｒｋｓ

to the right).

01-23

Machine sways, or a has shock during steering

90Z Ⅳ -2

QUICK TROUBLESHOOTING TABLE 01

Tire having different diameter

○

Large difference in air pressure of tires

○

Steering cylinders or circuit recently repaired

Shock is noticed only when steering fully to right or left

Use of equal diameter tires

○

Air pressure adjustment

○

Steering stopper bolt or bolts misadjusted or missing

Adjust stopper bolts

○

Roading the machine at too high speed ○

Ｓ ｏ ｌ ｕ ｔｉｏ ｎ Pin replacement or shim add

○ ○

Loose steering cylinder pin *

Air trapped in cylinders

Complaint is only while roading the machine

Shock is applied to the machine after quick steering

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ

Machine sways after quick steering

Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

7. Machine sways, or has a shock during steering

While the machine is travelling straight, the machine sways even if the steering wheel is held steady

Hydraulic Group

○

Reduce speed

○

Steer full L & R several times to purge air

* Have an operator quickly move the steering wheel right and left a few degrees. If the cylinder pin moves back & forth

＊ Ｒｅｍａｒｋｓ

replace the pin & bushings. If the cylinders jump up & down add shims.

01-24

90Z Ⅳ -2

Abnormal noise in hydraulic system

QUICK TROUBLESHOOTING TABLE 01

Hydraulic Group

Air drawn into pump suction line Internally broken pump

○

Noise may vary with engine speed or circuit being used

Increasing the engine speed emits a whining sound-Hydraulics slow

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ

Pump emits a shrieking sound

Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

8. Abnormal noise in hydraulic system

○ ○

High-pressure hose contact with chassis-loose sheet metal

Ｓ ｏ ｌ ｕ ｔｉｏ ｎ Hose band tightening and inspection Disassembly&repair

○

Hose clamp check and repair

Suction hose pinched or internally defective

○ ○

Inspect or replace hose

Suction line restricted

○ ○

Drain & inspect tank

01-25

90Z Ⅳ -2

Others

QUICK TROUBLESHOOTING TABLE 01

○

Disassembly&repair

○

Malfunctioning multiple control valve or pilot valve are sticking

Disassembly&repair

○

Disassembly&repair Tightening hose band

○

Air drawn into pump suction line

Pump disassembly and repair

○

Damaged hydraulic oil pump Pilot relief valve defective or misadjusted(pilot pressure too low) Excessive hydraulic oil temp, due to cooler problems or improper operation

Adjust or repair pilot relief

○

Cooler bypass valve stuck open

Ｓｏｌｕｔｉｏｎ Disassembly&repair

○

Clogged orifice of slow return check valve in boom line*

Oil milky white

Hydraulic cylinder packings leak repeatedly

When boom lever is set to "FLOAT" the boom goes only into power down.

(Engine may stall)

Hydraulic oil is mixed with the torque converter oil

Hydraulic oil is foaming

Boom or bucket control lever is too tight or too loose

When the boom lever is switched from "DOWN" to "NEUTRAL", the boom will continue to lower*

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ

Defective (incompletely closed) load check valve in multiple control valve boom line Defective(incompletely closed)load check valve in multiple control valve bucket line

When the bucket lever is set to "Roll-back" position, the bucket will be dumped slightly down first and then tilt back

Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

9. Others

When the boom lever is set to "UP" position, the boom will drop slightly first and then rise

Hydraulic Group

○

Test cooling Change operation

○

Remove & clean or replace

○ Drain & replace oil

Water in hydraulic oil

* Very cold or thick oil will also cause this symptom. If the problem stops when the oil warms up or the proper viscosity oil is ＊ Ｒｅｍａｒｋｓ

used the orifice is normal. Clogged slow return orifice will cause slow boom response in both up and down directions. (S/N 90C3-5701〜)

01-26

(2) Check the brake oil level.

(3) Check the brake piping for leakage

1. Brake does not work well (In the worst case, the brake does not work at all)

Check before starting work

(1) Check the air pressure.

Worn brake disk ○

Defective air master

Improperly aligned oil passages inside wheel hub

01-27 ○ ○ ○

Defective automatic adjuster valve

Damaged brake oil pipe ○ ○

Damaged brake piston seals one wheel ○ ○

Machine turns when the brake is applied suddenly (the steering wheel slips from your hands)

There is large difference in the oil pressure between the inlet and outlet of the automatic adjuster valve

When the brake pedal is pressed, the brake oil pressure of the front axle greatly differs from that of the rear axle. Air master stroke sensor rod is pushed out.

90Z Ⅳ -2

Both the right and left pedals have low braking resistance when pressed

When the brake pedal is pressed, the brake oil pressure of the front axle is almost equal to that of the rear axle

Defective brake valve Either the right or left brake pedal does not work

Measure the wear of the brake disk using calipers. The obtained wear value is less than the specified limit value.

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

Brake does not work well QUICK TROUBLESHOOTING TABLE 01

Brake Group

○

○

Ｓ ｏ ｌ ｕ ｔｉｏ ｎ

Disassembly&repair

Disassembly&repair

○ ○ Disassembly&repair

Disassembly&repair

○ Pipe replacement

Test leakage

Remove & realign

90Z Ⅳ -2

Brake is dragging when released

QUICK TROUBLESHOOTING TABLE 01

Brake Group 2. Brake is dragging when released

How to check dragging: (1) Check that the cover of the planetary gear is too

Stepping on brake pedal during traveling (Riding the brakes)

Manual rotation of the brake is not possible

Either the left or right wheel causes dragging

Either the front or rear axle causes dragging

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ

Manual rotation of the tire is possible

the tire is not possible.

Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

hot(more than 100 ° C).

(2) Jack up the tires, and check that manual rotation of

○

Ｓ ｏ ｌ ｕ ｔｉｏ ｎ Instruction for operator

Insufficient return of brake pedal

○

Disassembly&repair

Incomplete air bleeding from the brake oil circuit (air master section)

○

Disassembly, repair, and air bleeding Disassembly, repair, and air bleeding

○

Incomplete air bleeding from the brake circuit (axle end) Insufficient brake oil return due to defective air master check valve

○

Disassembly&repair

Insufficient return of air master piston

○

Disassembly&repair

Insufficient oil return due to defective automatic adjuster valve

○

Disassembly&repair

Distorted brake disk due to seizure

○

Disassembly&repair

Non-returned brake piston after replacement of brake disk

○

Disassembly&repair

01-28

90Z Ⅳ -2

Brake oil level lowers too much

QUICK TROUBLESHOOTING TABLE 01

Brake Group

Check before starting work (1) Check the type of the brake oil.

Oil is leaking from the air bleeder screw

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ

Oil leakage from front brake piston seal (flaw or swelling) Oil leakage from rear brake piston seal (flaw or swelling) Oil leakage from front axle end "O" ring seal (flaw or swelling) Oil leakage from rear axle end "O" ring seal (flaw or swelling)

Oil level of the brake oil tank lowers

Use of fluids other than those recommended will cause premature brake failure or inadequate braking.

Oil level of the brake oil tank lowers

WARNING

Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

(2) Check for brake oil leakage (External).

Oil tank level drops to, or below, "MIN" when brake is applied. It returns to "MAX" when brake is released.

3. Brake oil level lowers too much

○

Ｓ ｏ ｌ ｕ ｔｉｏ ｎ Disassembly&repair

○

Disassembly&repair

○

Disassembly&repair

○

Disassembly&repair Re-bleeding air, tighten

○

Loose bleeder screw

○

Brake plates warped in one or more wheels

01-29

Disassembly & repair

90Z Ⅳ -2

Stepping on brake pedal sounds buzzer

QUICK TROUBLESHOOTING TABLE 01

(brake valve to air master lines).

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ

Defective air master (overstroke)

the normal area when pedal is released.

(3) Step on the pedal, and check that air is not leaking

External pipe is oily, leaking

(2) Check the oil level of the brake oil tank.

Oil level of the brake oil tank lowers too rapidly

(1) Check the air pressure

Compressor on-load pressure is too low (Air governor setting)

Check before starting work:

Too much time is required for air charging

(3) Air master overstroke.

Buzzer sounds each time the brake pedal is stepped on

seconds or more).

Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

(2) Low oil level of brake oil tank (buzzer sounds for 3

Buzzer sounds when the pedal is repeatedly depressed

(1) Low air pressure (4.75kg/cm2 or less).

Pedal resistance is too low when depressed

Conditions for buzzer sounding:

Stroke switch of either the front or rear axle is actuated (pushed out)*

4. Stepping on the brake pedal sounds the buzzer

Oil tank level drops to, or below, "MIN" mark when pedal is applied. It returns to

Brake Group

○ ○ ○

Ｓ ｏ ｌ ｕ ｔｉｏ ｎ Disassembly&repair

Defective air governor (delay in loading compressor)

○ ○

Deteriorated performance of air compressor

○

Inspection &readjustment

○

Disassembly&repair

Large amount of oil leakage due to defective seal around ○ ○ ○ brake piston

○

Disassembly&repair

Brake oil piping damaged or loose

○ ○

Repair / tighten

○

Brake plates warped in one or more wheels

＊ Ｒｅｍａｒｋｓ

* To reset the air master stroke sensor it must be pushed fully in.

01-30

Disassembly&repair

90Z Ⅳ -2

Air pressure does not rise, or too slow

QUICK TROUBLESHOOTING TABLE 01

Disassembly &repair

○

Defective compressor outlet valve

Disassembly &repair

○

Worn compressor piston ring or liner

Disassembly &repair

○ ○ ○

Defective sensor

Replacement

○ ○ ○

Short circuit in gauge wiring

Repair cable

○ ○

Defective pressure gauge

Air leaking out from safety valve below pressure setting

Disassembly &repair

○

Defective compressor inlet valve

Ｓｏｌｕｔ ｉｏｎ Disassembly &repair

○

Defective compressor unloader valve

Defective air governor

Air temperature below freezing when problem occurs

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ

Ground the T-terminal of the gauge. The pointer of the gauge will not be deflected to the limit.

air circuit is defective.

Resistance value between the gauge terminals is not appropriate

(5) If both gauge and alarm light and buzzer are on the

Ground the E-terminal of the gauge. The gauge will properly indicate the value.

alarm light and buzzer are on-the alarm switch may be defective.

Voltage between the chassis and the A-terminal of the gauge is 24V or less

may be defective.

(4) If the gauge is in the normal (green) zone but the

Ground the T-terminal of the gauge. The pointer of the gauge will be deflected to the limit.

light and buzzer are not on-the gauge or sender

Resistance value of the sensor is not correct

hoses for damage.

(3) If the gauge is in the low (red) zone but the alarm

Open the drain cock of the air tank. Oil will be drained from the cock.

valve, and piping line for air leakage.

(2) Check the compressor inlet and outlet piping, and

Ground the sensor power line on the gauge side. The pointer of the gauge will be deflected to the limit.

(1) Check the air tank drain cock, automatic drain

Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

Check before starting work:

During operation, air blows out of the compressor outlet valve

is too small.)

During operation, air blows out of the compressor inlet valve

(Pressure indicated on the pressure gauge

During operation, remove the pipe from the governor unloader port. Air will not blow out of the port.

5. Air pressure does not rise, or too slow in rising.

During operation, remove the pipe from the governor unloader port. Air will blow out of the port.

Brake Group

Replacement

○ Adjust or replace

Safety valve is leaking or opening too early ○

Moisture / ice build-up in system

01-31

Warm & dry out system

90Z Ⅳ -2

Parking brake does not work

QUICK TROUBLESHOOTING TABLE 01

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ

Defective coil of parking solenoid valve

○

Sticking spool of parking solenoid valve

○ ○

Air leaking from line between solenoid valve and air cylinder Defective parking brake switch

○

Coil of the solenoid valve has extremely high or zero resistance

Unexpected movement of the machine may cause an accident resulting in injury or death.

To prevent such an accident, observe the following caution when manually releasing the parking brake : ・ Before releasing the parking brake, start the engine, and raise the brake air pressure to the specified value. After that, stop the engine. ・ After stopping the engine, apply the foot brake, and the machine will not move even if the parking brake is manually released. ・ If the foot brake cannot be applied chock the wheels to prevent the machine from moving.

Turning off the parking brake switch causes an air exhausting noise

WARNING

Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

(2) Check the air pressure.

Turning off the parking brake switch activates the link under the cylinder

(1) Check the fuses of the electrical system.

Setting the manual release knob of the solenoid valve to ON releases the parking brake (see "WARNING")

Check before starting work:

Parking brake remains unreleased

6. Parking brake does not work (or: Releasing the brake is not possible)

Brake does not work even if the parking switch is turned to "OFF" position

Brake Group

○

Ｓ ｏ ｌ ｕ ｔｉｏ ｎ Solenoid valve replacement Solenoid valve replacement

○

○

Inspection&repair

○ ○

○

Switch replacement

○

○

Repair cable

Disconnected or defective electrical line Sticking air cylinder

○ ○

○

Inspection&repair

Defective link between air cylinder and brake drum

○ ○

○ ○

Inspection&repair

Worn brake lining

○

○ ○

Readjustment

01-32

90Z Ⅳ -2

Engine hard to start or will not start

QUICK TROUBLESHOOTING TABLE 01

Before testing: Transmission shift lever must be in "NEUTRAL"

Ｅ ｌ ｅｃ ｔ ｒ ｉ ｃａ ｌ ｓｙｓ ｔ ｅｍ

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ

Cranking speed too low (100 rpm or less)

Machine may start & move suddenly during testing causing serious injury or death. ・ Never attempt to start the machine from the ground. ・ Securely chock the wheels to prevent movement.

Starter motor does not operate

WARNING

Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

position.

Engine cannot be stopped by turning off the key

1. Engine hard to start or will not start

When the starter switch is set to ON, the magnetic switch emits a chattering or clicking sound

Electrical Group

Ｓ ｏ ｌ ｕ ｔｉｏ ｎ

Fusible link is blown / removed

○

Diode pack (Cummins) blown / removed

○

Battery relay is defective

○

Inspection&repair

Neutral relay is defective

○

Inspection&repair

Battery charge low

○ ○

Starting circuit connections loose or corroded

○

Inspection&repair

Disconnected electrical wiring

○

Inspection&repair

Defective starter motor

○ ○

Inspection&repair

Defective starter switch or starter relay

○

Inspection&repair

Engine oil is too thick for cold weather

Inspection&repair

○

○

01-33

○

Inspection&repair

Battery charge

Change oil&viscosity

90Z Ⅳ -2

Engine will not stop

QUICK TROUBLESHOOTING TABLE 01

(or: Starting the engine is not possible.)

Check before starting work: (If the fusible link (30A) is failed, the engine can not be started.)

Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

(1) Check the fusible link (30A) for failed condition.

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ

Defective starter switch

Once stopped the engine will not start

2. Engine will not stop even if the starter switch is turned to "OFF".

Power will be continuously supplied to the starter switch B-BR terminal even if the starter switch is turned off

Electrical Group

○

Ｓ ｏ ｌ ｕ ｔｉｏ ｎ Switch replacement

Wiring error between units

Inspection&repair

○

Defective diode unit (shortcircuited diode) at battery relay

01-34

Diode replacement

Instrument panel does not indicate properly

90Z Ⅳ -2

QUICK TROUBLESHOOTING TABLE 01

Bulb of monitor lamp burnt out

Speed indicated on the instrument panel does not correspond with the speed set by the shift lever

T/M(transmission) solenoid valve does not operate based on the speed set by the shift lever

Hour meter does not operate

Pointers of all the gauges are deflected to their limits

○

Ｓ ｏ ｌ ｕ ｔｉｏ ｎ Bulb replacement

○

Defective sensor or improper wiring Disconnected or defective electrical circuit

One of the gauges does not indicate properly *

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ

All the gauge pointers do not move

controlled by rocker or toggle switches.

Pointer of the tachometer does not move

lamps-not green or amber lamps which are

One of the gauge pointers does not move

The lamp test circuit tests only the red warning

Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

(2) Lamp test

During operation, two or more monitor lamps light improperly *

(1) Check the fuses.

During operation, one of the monitor lamps lights improperly *

Check before starting work

One of the monitor lamps will not light after setting the starter key to ON

3. Instrument panel does not indicate properly

Two or more monitor lamps will not light after setting the starter key to ON

Electrical Group

○ ○

○ ○

○

Sensor replacement

○ ○ ○

○ ○ ○

Repairing cable

○

○ ○

Connector check and re-connection

Loose connector

○

○

T/M controller breaker turned off

○

Inspection&repair

T/M controller failure alarm turned on

○

Inspection&repair

Defective T/M controller

○ ○ ○

○ ○ ○

Defective inside mechanism of gauge or meter

○ ○ ○ ○

Defective board of instrument panel

Controller replacement Replacement Replacement

○ ○ Properly connect

T/M solenoid valves improperly connected

＊ Ｒｅｍａｒｋｓ

* If the gauge and warning lamps do not agree there probably is a defect in the wiring. Stop immediately and diagnose the defect. (Example: Air pressure gauge is in the lower red zone but the warning alarm does not come on. Probable cause: a defect in the gauge circuit. Confirm & repair immediately).

01-35

90Z Ⅳ -2

Breaker of the transmission controller

QUICK TROUBLESHOOTING TABLE 01

Clutch solenoid valve wire in contact with chassis (Wire chaffed or pinched by other components, etc.)

Clutch solenoid valve power line occasional contact with body Clutch solenoid valve coil shortcircuited (for all exc. trimmer)

○

Clutch solenoid valve diode failed

○

Neutral relay power line contact with chassis

○

Controller alarm relay power line occasional contact with chassis

Transmission has shift shock during each shift

Breaker is turned off when any speed or direction change is made

Breaker is turned off when a certain speed or direction is selected

Controller alarm lamp lights and will not go out

Both the forward and reverse shift lever position enable the engine to start

Coil of the solenoid valve has extremely low resistance

○

○

Inspection&repair

○

Solenoid valve replacement

○

Solenoid valve replacement

○ ○

Inspection&repair

○ ○

Inspection&repair

○

Inspection&repair

○

Inspection&repair

○ ○

Trimmer solenoid valve coil or wire short circuited

01-36

Ｓ ｏ ｌ ｕ ｔｉｏ ｎ Inspection&repair

○

Neutral relay power line occasional contact with chassis Controller alarm relay power line contact with chassis

Breaker is turned off if the machine sways during traveling

Ｐｏｓｓ ｉ ｂ ｌ ｅ ｃａｕｓｅ

Breaker is turned off immediately after turning on

Ｓｙｍｐ ｔ ｏｍｓ／ｃｈｅｃｋ ｐｏ ｉ ｎ ｔ

4. Breaker of the transmission controller is turned off

In the solenoid valve continuity test, change the positive and negative sides to each other. After that, power is still supplied to the solenoid valve

Electrical Group

Replace coil or repair wiring

MEASUREMENT FOR PERFORMANCE CHECK 03 Standard Measurement Values for Performance Check ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 03-2 Preparation for Performance Check ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 03-6 Measuring Engine Speed ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 03-8 Oil Pressure Gauge Port with Quick Coupler ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 03-12 Measuring Clutch Oil Pressure and Time Lag ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 03-13 Measuring Cylinder Drift ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 03-16 Measuring Boom Cycle Time ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 03-18 Measuring Full Steering Cycle Time ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 03-19 Measuring Relief Valve Setting Pressures ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 03-20 Checking Brake Performance ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 03-24 Measuring Air Line Setting Pressure ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 03-26 Measuring Air Charging Time ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 03-29 Measuring Number of Brake Pedal Applications ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 03-30 Measuring Declutch Engagement ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 03-31 Measuring Radiator Cooling Capability ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 03-32

03-1

90Z Ⅳ -2

Standard Measurement Values

MEASUREMENT FOR PERFORMANCE CHECK 03

Standard Measurement Values for Performance Check (S/N 90C3-5501〜5700) Measurement conditions : Temperature of torque converter oil : 50 to 80 ° C (120〜180 ° F) Temperature of hydraulic oil : 50 to 80 ° C (120〜180 ° F) Temperature of engine coolant : 50 to 80 ° C (120〜180 ° F) Item Measurement item

Standard measurement values for performance check

Minimum no-load speed, Low Idle (LI)

800 +50 -0

Maximum no-load speed, High Idle (HI)

2,350 ± 50

Maximum speed in torque converter stall mode

2,270 ± 100

Maximum speed in multiple control valve relief mode

2,200 ± 100

Transmission

Engine

System

Engine speed (min-1)(rpm)

Clutch pressure MPa(kgf/cm2) (psi)

Clutch time lag (sec)

Maximum speed in torque converter stall plus multiple control valve relief mode

+150 1,850 -100

Maximum speed in torque converter stall plus steering valve relief mode

+150 2,120 -100

Idling (LI)

1.3±0.2(13±2) (185±28)

Maximum (HI)

1.5±0.2(15±2) (213±28)

Engine speed

Neutral → Forward 1st speed (engine speed: 1500 -1 min (rpm))

Cylinder drift (when boom and bucket are Boom cylinder horizontal and with no load) (mm/min) Bucket cylinder (in/min)

Hydraulic pressure

Boom rising time (no load) (sec)

Full steering time (sec)

Relief valve setting pressure MPa(kg/cm2 ) (psi)

Remarks

Engine speed

Engine speed

0.3 ± 0.1

Before wheels move

3 (1/8) or less 4 (5/32) or less Idling (LI)

19 ± 3.0

1500 min-1(rpm)

9.1 ± 1.0

Maximum (HI)

6.1 ± 0.5

Idling (LI)

4.1 ± 0.5

-1

1500 min (rpm)

2.4 ± 0.3

Maximum (HI)

2.4 ± 0.3

Loading line main relief pressure (HI)

20.6±1.0(210±10) (2,990±142)

Loading line overload relief pressure (LI)

+ 0.5 +5 23.5 -1.0 (240 -10 ) + 71 (3,410 -142 )

Steering line main relief pressure (HI)

20.6±1.0(210±10) (2,990±142)

Steering line overload relief pressure (LI)

+ 0.5 24.5 -1.0 (250 -1+05 ) (3,560 -1+4271 )

Relief valve (LI)

3.7±0.3(38±3) (540±43)

Reducing valve (engine stop)

1.5±0.3(15±3.5) (213±50)

Pilot line

03-2

Run engine at lowest possible speed while setting

Run engine at lowest possible speed while setting

90Z Ⅳ -2

Standard Measurement Values

MEASUREMENT FOR PERFORMANCE CHECK 03

Item System

Measurement item Performance of service brake

Performance of parking brake

Shift lever position

2nd speed reverse

Engine speed

Maximum (HI)

Shift lever position

3rd speed reverse

Engine speed

Maximum (HI)

Brake

Air charge time (sec)

Remarks

Slowly increase the engine speed, and check that the machine does not move at the

Right brake pedal fully depressed and held down during test.

↑

Before brake check, be sure to disconnect the cable connector of parking brake solenoid valve

Off

637 -0+ 39 (6.5 -0+ 0.4 ) (92 -0+ 5.7 )

On

530 -0+ 39 (5.4 -0+ 0.4 ) (77 -0+ 5.7 )

Governor setting pressure Air line setting pressure kPa(kgf/cm2)(psi)

Standard measurement values for performance check

Safety valve setting pressure

834±39(8.5±0.4) (121±5.7)

Low-pressure alarm switch setting pressure

466±29(4.75±0.3) (68±4.3)

Engine speed -1 1500 min (rpm)

0 → 466kPa(4.75kgf/cm2)(68 psi) 2

0 → 637kPa(6.5kgf/cm )(92 psi)

45 ± 10 60 ± 10

2

Number of brake pedal applications

Declutch engagement (cm) (in)

Adjust the air tank internal pressure to 637kPa(6.5kgf/cm ) (92 psi)(governor cut-off pressure), and then stop the engine.

Turn key to "ON".

Step on the brake pedal and release, and check the number of times until the low-pressure alarm is turned on.

3 times or more

Repeat stepping on the brake pedal as follows: On : 5 sec.

Off : 5 sec.

Engine: Maximum speed / Inching pedal: Quick release

15 (6) or less

1/5 slope (approx. 11°), unladen, 1st speed

Radiator

Engine cooling water

Torque converter oil

Hydraulic oil

Balanced temperature when engine is at HI speed

Engine outlet temperature ( ℃ )

C above air temperature 40〜45 ° (72〜81 °F) above air temperature

Temperature difference between radiator inlet and outlet ( ℃ )

10〜15

Temperature difference between radiator inlet and outlet ( ℃ )

3〜5

03-3

90Z Ⅳ -2

Standard Measurement Values

MEASUREMENT FOR PERFORMANCE CHECK 03

Standard Measurement Values for Performance Check (S/N 90C3-5701〜) Measurement conditions : Temperature of torque converter oil : 50 to 80 ° C (120〜180 ° F) Temperature of hydraulic oil : 50 to 80 ° C (120〜180 ° F) Temperature of engine coolant : 50 to 80 ° C (120〜180 ° F) Item Measurement item

Standard measurement values for performance check

Minimum no-load speed, Low Idle (LI)

800 -+50 0

Maximum no-load speed, High Idle (HI)

2,350 ± 50

Maximum speed in torque converter stall mode

2,270 ± 100

Maximum speed in multiple control valve relief mode

2,200 ± 100

Transmission

Engine

System

Engine speed (min-1)(rpm)

Clutch pressure MPa(kgf/cm2) (psi)

Clutch time lag (sec)

Maximum speed in torque converter stall plus multiple control valve relief mode

+150 1,850 -100

Maximum speed in torque converter stall plus steering valve relief mode

+150 2,120 -100

Idling (LI)

1.3±0.2(13±2) (185±28)

Maximum (HI)

1.5±0.2(15±2) (213±28)

Engine speed

Neutral → Forward 1st speed (engine speed: 1500 min-1(rpm))

Cylinder drift (when boom and bucket are Boom cylinder horizontal and with no load) (mm/min) Bucket cylinder (in/min)

Hydraulic pressure

Boom rising time (no load) (sec)

Full steering time (sec)

Relief valve setting pressure MPa(kg/cm2 ) (psi)

Remarks

Engine speed

Before wheels move

3 (1/8) or less 4 (5/32) or less 19 ± 3.0

Idling (LI) Engine speed

0.3 ± 0.1

-1

1500 min (rpm)

9.1 ± 1.0

Maximum (HI)

6.1 ± 0.5

Idling (LI)

4.1 ± 0.5

1500 min-1(rpm)

2.4 ± 0.3

Maximum (HI)

2.4 ± 0.3

Loading line main relief pressure (HI)

20.6±1.0(210±10) (2,990±142)

Loading line overload relief pressure (LI)

+ 0.5 +5 23.5 -1.0 (240 -10 ) + 71 (3,410 -142 )

Steering line main relief pressure (HI)

20.6±1.0(210±10) (2,990±142)

Steering line overload relief pressure (LI)

+ 0.5 24.5 -1.0 (250 -1+05 ) (3,560 -1+4271 )

Pilot line

3.7±0.3(38±3) (540±43)

Relief valve (LI)

03-4

Run engine at lowest possible speed while setting

Run engine at lowest possible speed while setting

90Z Ⅳ -2

Standard Measurement Values

MEASUREMENT FOR PERFORMANCE CHECK 03

Item System

Measurement item Performance of service brake

Performance of parking brake

Shift lever position

2nd speed reverse

Engine speed

Maximum (HI)

Shift lever position

3rd speed reverse

Engine speed

Maximum (HI)

Brake

Air charge time (sec)

Remarks

Slowly increase the engine speed, and check that the machine does not move at the

Right brake pedal fully depressed and held down during test.

↑

Before brake check, be sure to disconnect the cable connector of parking brake solenoid valve

Off

637 -0+ 39 (6.5 -0+ 0.4 ) (92 -0+ 5.7 )

On

530 -0+ 39 (5.4 -0+ 0.4 ) (77 -0+ 5.7 )

Governor setting pressure Air line setting pressure kPa(kgf/cm2)(psi)

Standard measurement values for performance check

Safety valve setting pressure

834±39(8.5±0.4) (121±5.7)

Low-pressure alarm switch setting pressure

466±29(4.75±0.3) (68±4.3)

Engine speed -1 1500 min (rpm)

0 → 466kPa(4.75kgf/cm2)(68 psi) 2

0 → 637kPa(6.5kgf/cm )(92 psi)

45 ± 10 60 ± 10

2

Number of brake pedal applications

Declutch engagement (cm) (in)

Adjust the air tank internal pressure to 637kPa(6.5kgf/cm ) (92 psi)(governor cut-off pressure), and then stop the engine.

Turn key to "ON".

Step on the brake pedal and release, and check the number of times until the low-pressure alarm is turned on.

3 times or more

Repeat stepping on the brake pedal as follows: On : 5 sec.

Off : 5 sec.

Engine: Maximum speed / Inching pedal: Quick release

15 (6) or less

1/5 slope (approx. 11°), unladen, 1st speed

Radiator

Engine cooling water

Torque converter oil

Hydraulic oil

Balanced temperature when engine is at HI speed

Engine outlet temperature ( ℃ )

40〜45 ° C above air temperature F) above air temperature (72〜81 °

Temperature difference between radiator inlet and outlet ( ℃ )

10〜15

Temperature difference between radiator inlet and outlet ( ℃ )

3〜5

03-5

Preparation for Performance Check

90Z Ⅳ -2

MEASUREMENT FOR PERFORMANCE CHECK 03

Preparation for Performance Check WARNING

CAUTION

Unexpected movement of the machine may cause an accident resulting in injury or death. Therefore, to provide repair service with the engine running, be sure to observe the following items: ・ Park the machine on level ground. ・ Apply the parking brake. ・ Block the tires with chocks to prevent the tires from moving. ・ Determine the signals between the service men. ・ Prohibit any person from walking into dangerous areas. ・ Near articulation area of the machine ・ Under the machine ・ Around the engine ・ In front of or behind the machine

Do not touch the fan or V-belt of the engine or a high-temperature section if the engine is running. An accident resulting in injury may occur.

Be sure to stop the engine before you open the side cover of the engine room. Keep all guards in place.

Avoid high temperature components even when the engine is stopped.

・Preparation of measurement units ・ To measure pressure, be sure to prepare the hose, adapter, and wrench for pressure port plug in addition to the measurement instruments.

・Cautions regarding measurement ・ Take safety precautions before starting measurement work, and carefully measure and record the values. ・ Measure a value three times or more. If the obtained values greatly differs from each other, an error has been made in measuring the value.

Measure the value again.

Calculate the average value from the various readings.

・ Check operation of the measurement instruments.

Carefully handle the instruments. If something comes in contact with an instrument or large shock is applied to an instrument, the instrument may be damaged. In addition, periodic inspection of the insturments is also important. If the zero point of an instrument is not properly adjusted, the value indicated by the instrument may be wrong.

・Warm-up If the machine is too cold, measured values may be wrong. To prevent incorrect readings, be sure to warm up the machine until the torque converter oil, hydraulic oil, and engine coolant are heated to the specified temperature.

03-6

Preparation for Performance Check

90Z Ⅳ -2

・Procedure for warm-up

MEASUREMENT FOR PERFORMANCE CHECK 03

(140 ° F) (176 ° F) F) 60 ℃ 80 ℃ 100 ℃ (212 °

・ Torque converter oil temperature Perform torque converter stall operation by referring to "Stall speed measurement procedure".

Check the approximate temperature using the temperature gauge in the instrument panel.

・ Hydraulic oil temperature Perform multiple control valve relief operation by referring to "Engine speed measurement procedure in multiple control valve relief mode".

Check the approximate temperature using the contact thermometer attached to the outside surface of the hydraulic tank.

・ Engine coolant temperature Warming up the torque converter oil and hydraulic oil also warms up the engine.

Check the engine coolant temperature using the temperature gauge in the instrument panel.

03-7

F) 110 ℃ (230 °

Torque converter oil temperature gauge

(140 ° F) (176 ° F) 60 ℃ 80 ℃ F) 90 ℃ (194 ° F) 110 ℃ (230 °

Engine coolant temperature gauge

90Z Ⅳ -2

Measuring Engine Speed

MEASUREMENT FOR PERFORMANCE CHECK 03

Measuring Engine Speed WARNING

CAUTION

Unexpected movement of the machine may cause an accident resulting in injury or death. Therefore, to provide repair service with the engine running, be sure to observe the following items: ・ Park the machine on level ground. ・ Apply the parking brake. ・ Block the tires with chocks to prevent the tires from moving. ・ Determine the signals between the service men. ・ Prohibit any person from walking into dangerous areas. ・ Near articulation area of the machine ・ Under the machine ・ Around the engine ・ In front of or behind the machine

Do not touch the fan or V-belt of the engine or a high-temperature section if the engine is running. An accident resulting in injury may occur.

Be sure to stop the engine before you open the side cover of the engine room. Keep all guards in place.

Avoid high temperature components even after the engine is stopped.

・Measurement instrument ・ Tachometer drive port Note : A tachometer is already provided on the instrument panel. ・Warm-up the engine before measuring the engine speed

・Standard measurement value (min-1) (rpm) Minimum no-load speed (LI)

800 -+50 0

Maximum no-load speed (HI)

2,350 ± 50

Maximum speed in torque converter stall mode

2,270 ± 100

Maximum speed in multiple control valve relief mode

2,200 ± 100

Maximum speed in torque converter stall plus multiple control valve relief mode

+150 1,850 -100

Maximum speed in torque converter stall plus steering valve relief mode

+150 2,120 -100

03-8

Measuring Engine Speed

90Z Ⅳ -2

MEASUREMENT FOR PERFORMANCE CHECK 03

・Stall speed measurement procedure 1. Lower the boom to the lowest limit. Roll back the bucket fully until the bucket contacts to the stopper.

2. Record the High Idle (HI) engine speed.

3. Set the parking brake to the "OFF" position.

4. Press the right brake pedal all the way to the floor, and then set the transmission shift lever to the maximum forward speed position ("4").

Note : Cancel the auto shift mode (Refer to Section 32).

As a result the transmission shift lever"A" position works as "4" position.

5. Gradually increase the engine speed. Measure the engine speed when the accelerator pedal is fully pressed down.

IMPORTANT In the stall mode, the torque converter oil temperature rises rapidly. Therefore, long stall operation may damage the seals, and the damaged seal may cause oil leakage.

This is why stall operation should be limited to 5 seconds.

To repeat the stall operation, be sure to wait more than 5 seconds before next stall operation so that the torque converter oil is cooled enough.

Using this cycle safely warms up cold oil.

6. Record the engine RPM at T/C stall.

(During stall speed measurement, do not operate the steering system, boom, bucket, etc.)

7. Subtract T/C stall speed from HI speed.

・Engine speed measurement procedure in multiple control valve relief mode 1. Lower the boom to the lowest limit. Roll back the bucket fully until the bucket contacts to the stopper.

2. Set the parking brake to the "ON" position.

3. Set the engine speed to HI. 4. Place the bucket control lever in roll back position.

Measure the engine speed.

IMPORTANT When the relief valve is activated, the oil temperature rises rapidly. Therefore, long relief operation may damage the seals or cause the plunger to stick inside the valve.

This is why relief operation should be limited to 5 seconds.

To repeat the relief operation, be sure to wait more than 5 seconds before next relief operation, and cool the inside of the valve.

Using this cycle safely warms up cold oil.

03-9

Measuring Engine Speed

90Z Ⅳ -2

MEASUREMENT FOR PERFORMANCE CHECK 03

・Engine speed measurement procedure in steering valve relief mode Measure the engine speed with the following procedure in the torque converter stall mode.

1. Lower the boom to the lowest limit. Roll back the bucket fully until the bucket contacts to the stopper.

WARNING Do not enter the articulation area of the machine if the engine is running. An accident resulting in injury or death may occur.

To enter the articulation area, be sure to stop the engine, and remove the starter key. In addition, hang a "DO NOT START" tag on the steering wheel.

2. Slowly steer the machine fully to one side. Stop the engine. Remove the stopper bolt.

Note : Record the extention amount of the stopper bolt so that it can be reset to the original length later.

3. Start the engine. Set the parking brake switch to the "OFF" position.

4. Steer the machine until the front and rear chassis contact each other. Increase the engine speed, and measure the maximum speed.

Continue to turn the steering wheel while measuring and recording the engine speed.

5. Turn the machine full to the opposite direction and stop the engine.

Stop bolt 90K03001

6. Return the stopper bolt to the original position, and then tighten the locknut.

To check that the stopper bolt is properly positioned, press the accelerator all the way to the floor, and then quickly turn the steering wheel. Check that the front and rear chassis has only light contact .

If the front and rear chassis violently come in contact with each other, extend the stopper bolt.

If the front and rear chassis do not come in contact with each other, shorten the stopper bolt.

03-10

90Z Ⅳ -2

Measuring Engine Speed

・Cause of extremely high or low measurement value and solution

MEASUREMENT FOR PERFORMANCE CHECK 03

The engine speed is too high in torque converter stall plus multiple control valve relief (or steering valve relief) mode.

The engine speed is too high in torque converter stall mode.

Possible cause

Solution

Slipping transmission clutch or defect inside of transmission

Disassembly &repair

Defect inside torque converter

Disassembly & repair

Possible cause

Solution

Slipping transmission clutch or defect inside of transmission or T/C

Disassembly & repair

Relief pressure too low

Adjustment

Defective pump / pump seals

Disassembly & repair

The engine speed is too low in torque converter stall mode.

The engine speed is too low in torque converter stall plus multiple control valve relief (or steering valve relief) mode.

Caused by reduction in engine power Possible cause

Solution

Clogged air cleaner element

Cleaning

Improper type of fuel Clogged fuel filter or suction strainer Frozen fuel / wax build up Malfunctioning accelerator control link

Possible cause

Fuel replacement Clean or replace Use antifreeze mixture Adjustment

Defective fuel pump

Repair

Defective fuel injector nozzle

Repair

Insufficient compression pressure

Repair

The engine speed is too high in multiple control valve relief mode.

Possible cause

Solution

Relief valve pressure too low

Adjustment or disassembly

Defective pump / pump seals

Disassembly & repair

The engine speed is too low in multiple control valve relief mode.

Possible cause

Solution

Engine low power

Inspection & repair

Extremely high relief pressure of multiple control valve

Adjustment

03-11

Solution

Engine low power

Inspection & repair

Extremely high relief pressure of multiple control valve or steering valve

Adjustment

90Z Ⅳ -2

Oil Pressure Gauge Port with Quick Coupler

MEASUREMENT FOR PERFORMANCE CHECK 03

Oil Pressure Gauge Port with Quick Coupler

4 C Detail

Steering cylinder

2

3

1

3

4

2

3

A Detail

1

D Detail

B Detail

Gauge line

Relief valve

(For USA Spec.)

90V03001

1. T/M clutch oil pressure 2. Hydraulic line oil pressure 3. Steering line oil pressure

4. Pilot line oil pressure

03-12

Measuring Clutch Oil Pressure&Time Lag

90Z Ⅳ -2

MEASUREMENT FOR PERFORMANCE CHECK 03

Measuring Clutch Oil Pressure and Time Lag WARNING Unexpected movement of the machine may cause an accident resulting in injury or death. Therefore, to provide repair service with the engine running, be sure to observe the following items: ・ Park the machine on level ground. ・ Apply the parking brake. ・ Block the tires with chocks to prevent the tires from moving. ・ Determine the signals between the service men. ・ Prohibit any person from walking into dangerous areas. ・ Near articulation area of the machine ・ Under the machine ・ Around the engine ・ In front of or behind the machine

・ Measurement instruments:

・ Standard measurement value

・ Pressure gauge : 2.9MPa (30kgf/cm2) (500 psi) with 2〜3m (6〜10 ft. ) hose Pressure measurement port : PF1/4 O-ring port ・ Tachometer ・ Stop watch

・ Measure the engine speed and clutch oil pressure after warm-up

Clutch pressure MPa (kgf/cm2) (psi)

Clutch time lag (sec)

Idling(LI) Engine speed Maximum(HI) Neutral → 1st forward speed (engine speed : 1500min-1)

1.3±0.2 (13±2) (185±28) 1.5±0.2 (15±2 ) (213±28) 0.3 ± 0.1

・ Clutch oil pressure measurement procedure 1. Lower the boom to the lowest limit, and lower the bucket onto the ground.

2. Set the parking brake to the "ON" position.

3. Set the transmission shift lever to the neutral position.

4. Stop the engine. Attach the pressure gauge to the pressure measurement port. Place the gauge inside the operator's area, start the engine.

5. As the clutch oil pressure rises just after the engine is started, adjust the engine to the specified speed before the pressure measurement.

6. Measure and record the pressure in each speed range.

7. Change the transmission speed range while keeping the shift lever at the neutral position.

Check that the pressure instantaneously lowers just after speed change, and then rises to the original pressure again.

Transmission oil pressure test port location

03-13

Measuring Clutch Oil Pressure and Time Lag

90Z Ⅳ -2

MEASUREMENT FOR PERFORMANCE CHECK 03

T/C Inlet oil pressure (PT1/2)

3rd speed clutch oil pressure (PF1/4) Forward clutch oil pressure (PF1/4) Reverse clutch oil pressure (PF1/4)

2nd speed clutch oil pressure (PF1/4)

4th speed clutch oil pressure (PF1/4) 1st speed clutch oil pressure (PF1/4)

８５ＺＡ３３０１

Ｔ ｒ ａｎｓｍｉ ｓｓ ｉ ｏｎ ｏ ｉ ｌｐ ｒ ｅｓｓｕ ｒ ｅｔ ｅｓ ｔ ｐｏｒ ｔｌ ｏｃａ ｔ ｉ ｏｎ

03-14

90Z Ⅳ -2

Measuring Clutch Oil Pressure&Time Lag

・Time lag measurement procedure: 1. Lower the boom to the lowest limit, and fully roll back the bucket until the bucket contacts to the stopper.

2. Set the parking brake switch to the "OFF" position.

Do not apply the service brakes.

3. Set the transmission shift lever to the neutral 1st speed.

4. Keep the engine speed at 1,500min-1 (rpm).

5. Move the shift lever to the forward position. At the same time, start the stop watch to measure the time required before the machine moves. ・Possible causes for low clutch oil pressure and clutch time lag Clutch oil pressure

MEASUREMENT FOR PERFORMANCE CHECK 03

WARNING Unexpected movement of the machine may cause an accident resulting in injury or death.

To crawl under the machine, be sure to stop the engine, and block the tires with chocks to prevent them from moving. Give signals to the person in the cab during the work.

Trimmer solenoid valve From torque converter pump Regulator valve

Possible cause

Solution

Malfunctioning regulator valve operation

Disassembly & repair

Malfunctioning trimmer plug operation

Disassembly & repair

Broken spring

Disassembly & repair

Defective trimmer solenoid

Inspection & repair

Solution

Defective controller Note: If moving the shift lever causes the controller output LED "DC" indicator to blink, judge that the controller is OK.

Replacement

Defective electrical wire or connection to trimmer solenoid valve

Repair

Defective trimmer solenoid valve coil

Replacement

Sticking solenoid valve spool

Replacement

Malfunctioning control valve or regulator valve

Inspection & repair

Defective clutch

Disassembly & repair

Dragging brakes

Inspection & repair

Trimmer plug

Spool for manual operation

To each clutch solenoid valve

Clutch oil flow in transmission control valve regulator valve

Clutch time lag

Possible cause

To torque converter

03-15

90Z Ⅳ -2

Measuring Cylinder Drift

MEASUREMENT FOR PERFORMANCE CHECK 03

Measuring Cylinder Drift WARNING WARNING Standing under the boom or bucket during service work is dangerous. An accident resulting in injury or death may be caused.

To prevent such an accident, be sure to lock the boom and bucket control levers in the cab, securely support the boom, and remove the starter key.

In addition, hang a "DO NOT OPERATE!" tag on the steering wheel.

・Measurement instrument ・ Scale : 150 to 300mm (1 ft.) ・ Stop watch ・ Black vinyl "electrician's" tape ・Warm-up the cylinder drift

hydraulic

oil

Reference :

before

measuring

Drift rate depends on the viscosity of the hydraulic oil and its temperature. In other words, high temperature of the hydraulic oil reduces the viscosity. Reduction in oil viscosity increases oil leakage through the seals, and increases the drift rate. Cold thick oil reduces the drift rate.

・Standard measurement value(mm/min) (in/min) Boom cylinder

3 (1/8) or less

Bucket cylinder

4 (5/32) or less

・Measurement procedure 1. Unload the bucket.

2. Keep the boom and bucket horizontal.

3. Set the parking brake switch to the "ON" position.

4. Lock the boom and bucket control levers using the safety lock.

5. Stop the engine.

6. Attach vinyl tape to the cylinder rod at a point 100 to 150mm (4 〜 6 in) away from the cylinder head cover.

7. Measure the accurate distance from the cylinder head cover to the vinyl tape. This is distance "A" mm (in). Measure the distance again 5 minutes later. This is distance "B" mm (in).

A-B (mm) (in) Cylinder drift (mm/min) = 5 (min) (in/min)

03-16

Vinyl tape Scale

IMPORTANT At the completion of measurement, if the vinyl tape used for measurement is not removed from the cylinder rod, the tape may be caught by the rod seal. The tape will cause oil leakage from the rod seal. To prevent oil leakage, be sure to remove the vinyl tape.

90Z Ⅳ -2

Measuring Cylinder Drift

MEASUREMENT FOR PERFORMANCE CHECK 03

・Possible causes of excessive cylinder drift: Bucket cylinder

Possible cause

Solution

Damaged cylinder piston seal / barrel

Disassembly & repair

Defective multiple control overload relief valve

Disassembly & repair

Oil leakage from multiple control valve main spool

Disassembly & repair

Boom cylinder

Possible cause

Solution

Damaged cylinder piston seal / barrel

Disassembly & repair

Oil leakage in pilot relief valve

Disassembly & repair

Oil leakage from multiple control valve main spool

Disassembly & repair

To pilot valve

・ Identifying defective part (S/N 90C3-5501〜5700) There is a hose that supplies compressed oil from the bottom of the boom cylinder to the pilot relief valve.

Lower the boom and bucket to the ground and relieve all pressure. Remove the hose from the pilot relief valve, and plug the hose. Cap the fitting in the valve. Perform the cylinder drift test again. If the obtained cylinder drift rate is within the specified range, the cause is the internal leakage of the pilot relief valve.

If drift continues the leakage is in the boom cylinder or multiple control valve.

03-17

９０Ｋ０３００４

Relief valve

90Z Ⅳ -2

Measuring Boom Cycle Time

MEASUREMENT FOR PERFORMANCE CHECK 03

Measuring Boom Cycle Time WARNING Standing under the boom or bucket during service work is dangerous. An accident resulting in injury or death may occur.

Stay out of the area around the raised boom.

・Measuring instrument ・ Stop watch ・ Tachometer ・Warm-up the engine before measuring boom rising time ・Standard measurement value(sec)

Engine speed

Idling (LI)

19 ± 3.0

-1

1500min (RPM)

9.1 ± 1.0

Maximum (HI)

6.1 ± 0.5

・Measurement procedure 1. Unload the bucket.

2. Lower the boom to the lower limit, and roll back the bucket.

3. Set the parking brake switch to the "ON" position.

Stop the engine and install the tachometer.

4. Adjust the engine speed to the specified point.

5.Measure the time required for raising the boom from the lowest limit to the highest limit.

Note : Even if the boom kick out system (optional) is installed, the boom control lever should be held in the UP position until the boom rises to the highest limit.

・Possible causes of slow boom cycle time: Boom cylinder

Possible cause Damaged main pump / seals Damaged steering pump / seals Multiple control valve spool sticking

Solution Disassembly & repair Disassembly & repair

To steering line Multiple control Steering valve

Repair

How to determine the cause (damaged main pump or steering pump): Measure the full steering time. If normal the main pump is damaged. If steering time is also slow the steering pump is damaged.

03-18

Steering pump Main pump

Hydraulic oil tank

90Z Ⅳ -2

Measuring Full Steering Cycle Time

MEASUREMENT FOR PERFORMANCE CHECK 03

Measuring Full Steering Cycle Time WARNING Standing in the articulation area during service work is dangerous. An accident resulting in injury or death may occur.

During this test, prevent any person from walking around the machine or in the articulation area.

・Measurement instrument ・ Stop watch ・ Tachometer ・Warm-up the engine before measuring full steering time ・Standard measurement value(sec)

Engine speed

Idling (LI)

4.1 ± 0.5

-1

1500min (RPM)

2.4 ± 0.3

Maximum (HI)

2.4 ± 0.3

・Measurement procedure 1. Unload the bucket.

2. Lower the boom to the lower limit, and roll back the bucket.

3. Set the parking brake switch to the "OFF" position and release the brake pedal.

4. Adjust the engine speed to the specified point.

5. Measure and record the time required for full steering. ・ From full left to full right or ・ From full right to full left Turn the steering wheel as fast as possible during the test.

Full steering

・Possible causes for slow steering times: Possible cause

Solution

Damaged steering pump / seals

Disassembly & repair

Malfunctioning steering valve flow control plunger

Disassembly & repair

Flow control plunger

Steering valve 90Z Ⅳ 0301

03-19

Measuring Relief Valve Setting Pressures

90Z Ⅳ -2

MEASUREMENT FOR PERFORMANCE CHECK 03

Measuring Relief Valve Setting Pressures WARNING Unexpected movement of the machine may cause an accident resulting in injury or death. Therefore, to provide repair service with the engine running, be sure to observe the following items: ・ Park the machine on level ground. ・ Apply the parking brake. ・ Block the tires with chocks to prevent the tires from moving. ・ Determine the signals between the service men. ・ Prohibit any person from walking into dangerous areas. ・ Near articulation area of the machine ・ Under the machine ・ Around the engine ・ In front of or behind the machine

CAUTION Do not touch the fan or V-belt of the engine or a high-temperature section if the engine is running. An accident resulting in injury may occur.

Be sure to stop the engine before you open the side cover of the engine room. Keep all guards in place.

Avoid high temperature components even after the engine is stopped.

Reference :

CAUTION Be careful, you may get burned if the high pressure oil spouts out. To prevent such an accident, be sure to release the residual pressure from the pipe, and open the cap of the hydraulic oil tank before removing the plug from the pressure measurement port.

Releasing residual pressure from pipe Keep the bottom surface of the bucket horizontal, and stop the engine when the bucket is approximately 30cm(1 ft.) above the ground.

Tilt down the bucket until it comes in contact with the ground. Place the bucket control lever in the roll back position, and then lower the boom.

Open the cap of the hydraulic oil tank.

03-20

Measuring Relief Valve Setting Pressures

90Z Ⅳ -2

・Measurement instruments: 2 ・ Pressure gauge 29.4MPa(300kgf/cm )(5,000psi) (for loading and steering lines) with 1.5〜3m (4〜10 ft. ) hose 2 4.9MPa (50kgf/cm ) (1,000 psi) (for pilot line) with 2 〜 3m (6 〜 10 ft. ) hose Pressure measurement port: JIS PF 1/4 O-ring port Note : For safety, route the gauge to an area where it may be safely read by the person doing the test.

MEASUREMENT FOR PERFORMANCE CHECK 03

Tilt cylinder

(S/N 5701〜)

・Warm-up the engine before measuring relief valve setting pressures ・Standard measurement value MPa(kgf/cm2 )(psi) Loading line main relief pressure (at maximum speed)

20.6 ± 1(210 ± 10) (2,990 ± 140)

Loading line overload relief pressure (at idling speed)

23.5 ±0.51 (240 ±105 ) 70 (3,410 ±140 )

Steering line main relief pressure (at maximum speed)

20.6 ± 1(210 ± 10) (2,990 ± 140)

Steering line overload relief pressure (at idling speed)

24.5 ±0.51 (250 ±105 ) 70 (3,560 ±140 )

Pilot line

Relief valve (at Idling speed)

3.7 ± 0.3(38 ± 3) (540 ± 43)

Reducing valve ＊ (at engine stopped)

1.5 ± 0.3(15 ± 3.5) (213 ± 50)

＊ Operational check only. (S/N 90C3-5501〜5700)

(〜S/N 5700)

90K03005

Pressure gauge port for measurement of multiple control valve main relief pressure and bucket cylinder bottom side overload relief pressures Main relief valve

Bucket cylinder bottom side overload relief valve

・Measuring loading line main relief pressure 1. Unload the bucket.

2. Lower the boom to the lowest limit.

2 3. Attach the pressure gauge 29.4MPa (300kgf/cm ) (5,000 psi) 4. Set the parking brake switch to the "ON" position.

5. Move the bucket control lever to the roll back position. Hold the lever at that position.

6. Increase the engine speed to the maximum, and measure and record the pressure using the pressure gauge.

Bucket cylinder rod side overload relief valve

Relief poppet Adjusting screw

Plunger Tank port

・Measuring loading line overload relief pressure (bucket cylinder bottom side) 1.Adjust the main relief valve pressure to 2 26.5MPa(270kgf/cm )(3,800 psi) where the pressure is above the overload relief pressure.

Pump port

90Z Ⅳ 0302

Multiple control valve, Main relief valve

03-21

Measuring Relief Valve Setting Pressures

90Z Ⅳ -2

MEASUREMENT FOR PERFORMANCE CHECK 03

Reference : One turn of the main relief valve pressure adjustment screw increases or reduces the 2 pressure approximately 17.7MPa(180kgf/cm ) (2,560 psi).

2. Measure and record the overload relief pressure by following the main relief pressure measurement procedure described above. Note that the engine speed should be kept as low as possible during pressure measurement.

・Measuring loading line overload relief pressure (on bucket cylinder rod side) Refer to the measurement procedure for the cylinder bottom side, and observe the following points: ・ Keep the boom horizontal. ・ Move the bucket control lever to the dump position, hold, and then measure and record the pressure.

Tilt cylinder

(S/N 5701〜)

(〜S/N 5700)

90K03006

Pressure gauge port for measurement of bucket cylinder rod side overload relief pressure

IMPORTANT At the completion of check and adjustment of overload relief valve pressure, be sure to reset the main relief valve to the original condition.

・Measuring steering line main relief pressure 1. Set the steering oil pressure to the relief by following the procedure for "Engine speed measurement procedure in steering valve relief mode".

2. Measure and record the relief pressure when the engine speed is at its maximum. ・Measuring steering line overload relief pressure on right side 1. Adjust the main relief valve pressure to 26.5MPa 2 (270kgf/cm ) (3,800 psi) where the pressure is above the overload relief pressure.

90K03007

Pressure gauge port for measurement of steering relief pressure and overload relief pressure

Overload relief valve Front

Overload relief valve

Main relief valve 90K03008

Steering valve

03-22

Measuring Relief Valve Setting Pressures

90Z Ⅳ -2

MEASUREMENT FOR PERFORMANCE CHECK 03

Reference : One turn of the main relief valve pressure adjustment screw (2) increases or reduces the 2 pressure approximately 17.7MPa(180kgf/cm )(2,560 psi).

2

2. Measure and record the overload relief pressure by following the steering line main relief pressure measurement procedure described above. Note that the engine speed should be kept as low as possible during pressure measurement.

1

1. Locking jam nut 2. Adjusting screw

・Measuring steering line overload relief pressure on left side Attach the pressure gauge to the right cylinder, and then measure and record the pressure by following the pressure measurement procedure described above.

Steering valve main relief valve

IMPORTANT Relief valve

At the completion of check and adjustment of overload relief valve pressure, be sure to reset the main relief valve to the original condition.

・Measuring pilot line relief pressure 2 1. Attach the pressure gauge 4.9MPa (50kgf/cm ) (1,000 psi) 2. Lower the boom to the lowest limit.

3. Unload and roll back the bucket fully till the bucket contacts to the stopper. Hold this position.

4. Measure and record the relief pressure when the engine speed is at low idle speed. ・Pilot line pressure reducing valve - operational check (S/N 90C3-5501〜5700) 1. Fully roll back the bucket.

2. Lower the boom to about 50cm (20 in.) above the ground.

3. Stop the engine.

4. Slowly push the boom lever to the "Boom Down" position.

5. If the boom moves down the pilot pressure reducing valve is operating normally (reducing pressure is approximately 1.5MPa (15kgf/cm2) 〔213 psi〕).

If the boom will not lower start the machine, lower the boom and bucket, relieve tank pressure, and stop the engine.

Remove and inspect the pressure reducing valve.

Clean or replace as necessary.

03-23

90K03009

Pressure gauge port for measurement of pilot line relief pressure

Relief valve

90K03010

Pressure gauge port for measurement of pilot line reducing pressure

90Z Ⅳ -2

Checking Brake Performance

MEASUREMENT FOR PERFORMANCE CHECK 03

・Cause of extremely high or low measurement value and solution The set pressure is too high.

The set pressure is too low.

Possible cause

Solution

Possible cause

Solution

Pressure setting screw not set properly

Adjustment

Pressure setting screw not set properly

Adjustment

Relief valve spring broken

Disassembly & repair

Debris stuck in valve

Disassembly & cleaning

Damaged pump / seals

Disassembly & repair

If the inside of the pump is damaged, boom rising time and steering time may be also slow.

The pilot pump damage may only reduce pilot pump pressure.

Checking Brake Performance WARNING

Parking brake:

Unexpected movement of the machine may cause an accident resulting in injury or death.

Before starting brake performance check, be sure to observe the following items: ・ Place the machine on level ground. ・ Check that there is enough clearance for brake performance check around the machine. ・ During performance check, prohibit any person to walking near the machine.

・Measurement instrument None ・Warm-up the performance

engine

before

checking

brake

・Test on hard level ground ・Standard measurement value Service brake: Shift lever position Engine speed Left brake pedal T/M cut-off switch

2nd reverse speed Maximum speed Fully depressed

Shift lever position

3rd reverse speed

Engine speed

Maximum speed

Parking brake switch

"OFF" (Parking brake solenoid valve wire disconnected)

Slowly increase the engine speed, and check that the machine does not move at the maximum engine speed.

・Checking performance of service brake 1. Lower the boom to the lowest limit, and roll back the bucket fully until the bucket contacts to the stopper.

2. Set the parking brake switch to the "OFF" position.

3. Set the T/M (transmission) cut-off switch to OFF, and then depress the left brake pedal all the way to the floor.

4. Set the shift lever to 2nd reverse speed.

5. Gradually increase the engine speed. The machine should not move at the maximum engine speed.

Slowly increase the engine speed, and check that the machine does not move at the maximum engine speed.

"OFF"

03-24

90Z Ⅳ -2

Checking Brake Performance

MEASUREMENT FOR PERFORMANCE CHECK 03

・Checking performance of parking brake 1. Steer the machine to the right side. Lower boom and bucket to the ground. Stop the engine.

Remove the connector of the electrical line from the parking brake solenoid valve to apply the parking brake.

2. Start the engine. Lower the boom to the lower limit, and roll back the bucket until it contacts the stopper.

3. Set the shift lever to 3rd reverse speed.

4. Gradually increase the engine speed. The machine should not move at the maximum speed.

IMPORTANT If the machine begins to move with the parking brake applied, the brake shoes are burnt or misadjusted.

At the completion of parking brake test, be sure to connect the connector of electrical line to the solenoid valve again.

Solenoid valve Remove the harness

65K03007

・Cause of machine moving performance check and solution

during

brake

Service brake

Parking brake

Possible cause

Solution

Brake air pressure too low

Check and adjustment

Possible cause Clearance between brake drum and

Solution

shoe too large

Clearance adjustment

Brake oil pressure too low

Check and adjustment

Improperly adjusted air cylinder stroke

Check and adjustment

Worn brake disk

Check and repair

Broken air cylinder spring

Check and repair

03-25

90Z Ⅳ -2

Measuring Air Line Setting Pressure

MEASUREMENT FOR PERFORMANCE CHECK 03

Measuring Air Line Setting Pressure WARNING

CAUTION

Unexpected movement of the machine may cause an accident resulting in injury or death. Therefore, to provide repair service with the engine running, be sure to observe the following items: ・ Park the machine on level ground. ・ Apply the parking brake. ・ Block the tires with chocks to prevent the tires from moving. ・ Determine the signals between the service men. ・ Prohibit any person from walking into dangerous areas. ・ Near articulation area of the machine ・ Under the machine ・ Around the engine ・ In front of or behind the machine

Do not touch the fan or V-belt of the engine or a high-temperature section if the engine is running. An accident resulting in injury may occur.

Be sure to stop the engine before you open the side cover of the engine room. Keep all guards in place.

Avoid high temperature components even when the engine is off.

Air governor

・Measurement instrument ・ Air pressure gauge : 2 1471kPa (15kgf/cm ) (200 psi) with 2.5〜3m (8〜10ft. ) hose Pressure measurement port :PT1/4 Note : For safety, route the gauge to an area where it may be safely read by the person doing the test. ・Standard measurement value kPa(kgf/cm2 )(psi) off 637 ±390 (6.5 ±0.4 0 )(92〜98) Governor setting pressure

on 530 ±390 (5.4 ±0.4 0 )(76〜85)

Safety valve setting pressure

834 ± 39 (8.5 ± 0.4) (120 ± 5)

Low-pressure alarm switch

466 ± 29 (4.75 ± 0.3)

setting pressure

Air Compressor 85K03013

Attachment of pressure gauge for measurement of air line pressure

(67 ± 4)

・Measuring air pressure Measuring governor set pressure 1. Lower the boom to the lowest limit, and tilt down the bucket onto the ground.

2. Set the parking brake switch to the "ON" position and stop the engine.

3. Discharge air pressure.

4. Attach the pressure gauge.

5. Start the engine, and keep the speed at low idle.

6. Measure and record the pressure when the pointer of the pressure gauge stops rising (compressor off).

7. Keep the engine at low idle, and repeatedly depress and release the brake pedal to reduce the air pressure. Measure and record the pressure when the pointer of the pressure gauge stops and then starts rising again (compressor on).

03-26

8

7

6

5

Air governor

4

3

2

1

1.Cover 2.Locknut 3.Body 4.Adjustment screw 5.Spring guide 6.Exhaust stem 7.Piston 8.Exhaust valve

90Z Ⅳ -2

Measuring Air Line Setting Pressure

・ Measuring air pressure setting for safety valve 1. Stop the engine. Turn the governor pressure adjustment screw (4) 3.5 turns counterclockwise to set the compressor off pressure to approximately 2 981kPa(10kgf/cm ) (140 psi).

2. Start the engine, and measure and record the air pressure when the safety valve is activated (air is discharged) .

3. Reset the air governor pressure to the original point.

・ Measuring air pressure low-pressure alarm switch

setting

MEASUREMENT FOR PERFORMANCE CHECK 03

IMPORTANT Extremely high air pressure may damage the braking system.

At the completion of safety valve setting pressure check, be sure to reset the governor pressure to the original point.

for

1. Check that the pressure inside the air tank is 2 588kPa (6kgf/cm ) (85psi) and then stop the engine.

2. Set the starter key to ON. 3. Slightly open one of the drain cocks on the air tank.

Slowly reduce the air pressure. Measure and record the pressure when the low-pressure alarm buzzer sounds.

・Possible causes of extremely high or low air pressure The governor set pressure is too high

Possible cause

The governor set pressure is too low

Solution

Governor adjustment screw not set properly

Readjustment

Air leakage from the pipe line between the compressor unloader valve and governor

Check and adjustment

Governor adjustment screw not set properly

Readjustment

Governor replacement

Insufficient compressor compression

Damaged inside of governor

Disassembly & repair

Disassembly & repair

Defective compressor outlet valve

Defective compressor unloader valve

Disassembly & repair

Defective compressore unloader valve

Disassembly & repair

Damaged inside of governor

Governor replacement

Air leakage from pipe or drain cock

Check and repair

Possible cause

03-27

Solution

90Z Ⅳ -2

Measuring Air Line Setting Pressure

MEASUREMENT FOR PERFORMANCE CHECK 03

Reference : Safety valve pressure not set properly

Possible cause

Solution

Adjustment nut not set properly

Readjustment

Rust, dirt, corrosion in valve / tank

Clean or replace

・ Adjusting pressure by governor adjustment screw.

2 Approx. 98kPa (1kgf/cm ) (14 psi) by turning screw 360 ° (1 turn) ・ If pressure adjustment on both sides (governor-on and governor-off sides) is not possible (adjusting one side of pressure causes the other side of pressure to be out of the specified range), be sure to adjust the governor-on pressure to the specified range.

1 2

3 4 1. Adjustment nut 2. Locknut 3. Spring 4. Ball Safety valve

Low pressure alarm switch not set properly

Possible cause

Solution

Defective low pressure alarm switch

Replacement

Disconnected switch or broken wire

Connect or repair

03-28

90Z Ⅳ -2

Measuring Air Charging Time

MEASUREMENT FOR PERFORMANCE CHECK 03

Measuring Air Charging Time CAUTION

WARNING Unexpected movement of the machine may cause an accident resulting in injury or death. Therefore, to provide repair service with the engine running, be sure to observe the following items: ・ Park the machine on level ground. ・ Apply the parking brake. ・ Block the tires with chocks to prevent the tires from moving. ・ Determine the signals between the service men. ・ Prohibit any person from walking into dangerous areas. ・ Near articulation area of the machine ・ Under the machine ・ Around the engine ・ In front of or behind the machine

Do not touch the fan or V-belt of the engine or a high-temperature section if the engine is running. An accident resulting in injury may occur.

Avoid high temperature components even when the engine is stopped.

・Measurement instrument ・ Air pressure gauge : 2 981kPa (10kgf/cm ) (140psi) with 2.5〜3m (8〜10 ft. ) hose Pressure measurement port :PT1/4

・Possible causes of extremely high measurement value and solution

・ Tachometer ・ Stop watch Note : For safety, route the gauge to an area where it may be safely read by the person doing the test. ・Standard measurement value (sec) -1 Engine speed: 1,500min (rpm)

The air charging time is too long

Possible cause

Solution

Defective compressor unloader valve

Disassembly & repair

& Defective compressor inlet or outlet valve Disassembly repair Worn compressor piston ring or liner

Disassembly & repair

Air leakage from pipe (large amount)

Check and repair

0 → 466kPa(4.75kgf/cm2)(67psi)

45 ± 10

Defective air governor

Disassembly & repair

0 → 637kPa (6.5kgf/cm2) (92psi)

60 ± 10

Air leakage at safety valve

Adjustment or replace

・Measurement procedure 1. Lower the boom to the lowest limit, and tilt down the bucket to the ground.

2. Set the parking brake switch to the "ON" position.

3. Stop the engine. Open the drain cock of the air tank to reduce the air pressure into zero.

4. Attach the pressure gauge and tachometer.

5. Start the engine, and keep the engine speed at 1,500min-1 (rpm).

6. Close the drain cock, and measure and record the time required for pressure increase to the specified value.

03-29

90Z Ⅳ -2

Number of Brake Pedal Applications

MEASUREMENT FOR PERFORMANCE CHECK 03

Measuring Number of Brake Pedal Applications WARNING

CAUTION

Unexpected movement of the machine may cause an accident resulting in injury or death. Therefore, to provide repair service with the engine running, be sure to observe the following items: ・ Park the machine on level ground. ・ Apply the parking brake. ・ Block the tires with chocks to prevent the tires from moving. ・ Determine the signals between the service men. ・ Prohibit any person from walking into dangerous areas. ・ Near articulation area of the machine ・ Under the machine ・ Around the engine ・ In front of or behind the machine

Do not touch the fan or V-belt of the engine or a high-temperature section if the engine is running. An accident resulting in injury may occur.

Avoid high temperature components even when the engine is stopped.

・Measurement instrument ・ Air pressure gauge : 2 981kPa (10kgf/cm ) (140psi) with 2.5〜3m (8〜10 ft. ) hose Pressure measurement port :PT1/4 Note : For safety, route the gauge to an area where it may be safely read by the person doing the test.

・Possible causes of extremely low measurement value and solution Possible cause Defective brake valve Air master overstroke due to low / leaking brake oil

Check and repair

Defective air master

Check and repair

Air leakage from pipe (large amount)

Check and repair

・Standard measurement value Number of brake pedal applications while brake tank pressure is lowering from 637kPa(6.5kgf/cm2)(92psi) to 466kPa(4.75kgf/cm2)(67psi)

3 times or more

・Measurement procedure 1. Lower the boom to the lowest limit, and tilt down the bucket to the ground.

2. Set the parking brake switch to the "ON" position.

Stop the engine. Discharge air pressure.

3. Attach the pressure gauge and start the engine.

4. Increase the air tank pressure to 637kPa(6.5kgf/cm2) (92 psi) (compressor-off pressure), and stop the engine.

Turn the starter switch to "ON".

5. Depress the right brake pedal all the way to the floor, and hold down the pedal for 5 seconds.

Release the pedal, and wait for 5 seconds to depress the pedal again. Repeat.

6. Count and record the number of pedal applications until the tank pressure lowers to 466kPa (4.75kgf/c m2) (67 psi) (low-pressure alarm point).

Note : The gauge should go into the red zone and the alarm should come on at about the same time and pressure.

03-30

Solution Check and repair

90Z Ⅳ -2

Measuring Declutch Engagement

MEASUREMENT FOR PERFORMANCE CHECK 03

Measuring Declutch Engagement WARNING Checking the machine on a slope is dangerous work. An accident resulting in injury or death may occur.

Before starting declutch engagement test observe the following: ・ Check that the slope is smooth. ・ Check that the brake works well. ・ Prohibit any person from walking into the dangerous area. ・ Determine the signs between the service men. ・ Do not enter the area near the moving machine. ９０Ｋ０３０１１

・Measurement instrument ・ Chalk ・ Scale (approx. 1 m) (3 ft.) or tapemeasure ・ Thin rod (approx. 1 m) (3 ft.) used as measurement rod ・ Vinyl tape ・ Assistant / operator ・ Nylon tie straps (2 or 3)

Measurement rod attached to step

・Cause of extremely high measurement value and solution

・Warm-up the engine before measuring declutch engagement ・Standard measurement value 1/5 slope (approx. 11 ° ), unloaded bucket, engine maximum speed at 1st speed position, quickly released inching pedal

15cm (6 in) or less

・Measurement procedure 1. Attach the measurement rod to the step.

2. Position the boom approximately 50 cm (1 1/2 ft.) above the ground. Roll the bucket fully back until the bucket contacts to the stopper.

3. Stop the machine on a 1/5 slope (approx. 11 ° ) so that the machine is in the climbing direction (bucket up hill) .

4. Set the inching cut-off switch to ON. 5. Set the parking brake switch to the "OFF" position.

6. Press the inching brake pedal (left pedal) all the way to floor.

7. Mark the ground at the pointer position with chalk or tape. Increase the engine speed to its maximum, and set the transmission shift lever to the 1st forward speed.

8. Quickly release the inching brake pedal, and mark the point at which the machine stops rolling back (using the pointer) and starts moving up the slope.

9. Measure and record the distance on the slope from step 7 to step 8.

03-31

Possible cause

Solution

Too much delay in resetting declutch switch

Check and replace declutch sw

Too much time lag in engaging clutch

Refer to "Time lag measurement procedure" .

Measuring Radiator Cooling Capability

90Z Ⅳ -2

MEASUREMENT FOR PERFORMANCE CHECK 03

Measuring Radiator Cooling Capability WARNING

CAUTION

Unexpected movement of the machine may cause an accident resulting in injury or death. Therefore, to provide repair service with the engine running, be sure to observe the following items: ・ Park the machine on level ground. ・ Apply the parking brake. ・ Block the tires with chocks to prevent the tires from moving. ・ Determine the signals between the service men. ・ Prohibit any person from walking into dangerous areas. ・ Near articulation area of the machine ・ Under the machine ・ Around the engine ・ In front of or behind the machine

Do not touch the fan or V-belt of the engine or a high-temperature section if the engine is running. An accident resulting in injury may occur.

・Measurement instrument ・ Contact thermometer ・Standard measurement value( ° C) Coolant temperature at engine outlet ＊

40〜45 ° C above air temperature (72〜81 ° F above air temperature)

Difference in torque converter oil temperature between cooler inlet and Difference in hydraulic oil temperature between cooler inlet and outlet

10〜15 ° C (18〜27 ° F) 3 〜5 ° C (5〜9 ° F)

・Measurement procedure 1. Lower the boom to the lowest limit, and tilt down the bucket to the ground.

2. Set the parking brake switch to the "ON" position.

3. Apply no load to the engine, and increase the speed to its maximum.

4. Measure the temperature of coolant, torque converter oil, and hydraulic oil at each point when the temperature stops rising (stable temperature status).

Note : To judge whether the temperature is stable, check the water temperature gauge and torque converter oil temperature gauge (in the operator's room) and outer surface of the hydraulic oil tank.

C the coolant ＊ For example, if air temperature is 26 ° temperature should stabilize at about 66 ° 〜71 ° C. (80 ° F should stabilize at about 152 ° 〜161 ° F).

03-32

Coolant inlet

Hydraulic oil outlet Coolant bypass line inlet Torque converter oil outlet

Coolant drain Hydraulic oil inlet Torque converter oil inlet Coolant outlet

90Z Ⅳ 0303

Temperature measurement points at radiator inlet and outlet

90Z Ⅳ -2

Measuring Radiator Cooling Capability

・Possible causes of extremely measurement value and solution

high

or

low

The engine coolant is overheated

Possible cause

MEASUREMENT FOR PERFORMANCE CHECK 03

The torque converter oil is overheated

Solution

Possible cause

Solution

Damage inside torque converter

Disassembly & repair

Distorted or damaged fan

Replace

Damaged transmission clutch

Disassembly & repair

Improper lap clearance of fan and fan shroud

Repair

Torque converter pump discharge amount too small

Disassembly & repair

Clogged radiator fin ＊

Clean

Water pump output too low

Repair

Torque converter inlet or outlet relief Disassembly & pressure too low repair

Scale deposited inside radiator water tubes

Cleaning

Malfunction of thermostat

Replace

Insufficient air flow

Reduction in fan speed due to belt Tension check and slippage adjustment

Overload due to damage inside torque converter

Disassembly & repair

Overload due to damage transmission clutch

Disassembly & repair

Overheated torque converter oil

Refer to "The torque converter oil is overheated" described above.

Brakes dragging

Check & repair

The hydraulic oil is overheated

Possible cause

Solution

Cooler bypass valve remains open

Disassembly & repair

Pump discharge amount too small

Disassembly & repair

Clogged return filter

Check and cleaning

Insufficient air flow

Refer to "The engine coolant is overheated" described above.

Clogged hydraulic oil cooler ＊

Clean

＊ Be sure to check for clogging between the hydraulic oil

cooler and the radiator. This not visible from the fan side. The oil cooler must be removed to check and clean completely.

03-33

Water pump output too low

Disassembly & repair

Scale deposited in coolant side for torque converter cooler

Disassembly & clean

Overheated engine coolant

Refer to "The engine coolant is overheated" described

Debris inside cooler from T/M or T/C failure

Replace

Brakes dragging

Check & repair

90Z Ⅳ -2

Measuring Radiator Cooling Capability

MEASUREMENT FOR PERFORMANCE CHECK 03

Hydr. Cooler

９０ＺⅣ０３０４

Radiator

Rear chassis

Transmission

90K03012

03-34

90Z Ⅳ -2 Troubleshooting,Measurement for Performance Check AAA-S90C3V01-979 AAA-S90C3V01-012

① 1997.9

K

② 2001.2

KAWASAKI HEAVY INDUSTRIES, LTD. Rolling Stock, Construction Machinery & Crushing Plant Company Construction Machinery Division Tokyo Head Office

W.T.C. Bldg., 2-4-1 Hamamatsu-cho Minato-ku, Tokyo 105-6116

Kobe Head Office

Kobe Crystal Tower, 1-1-3 Higashi Kawasaki-cho Chuo-ku, Kobe, Hyogo 650-0044

Banshu Works

2680 Oka Inami-cho Kako-gun, Hyogo 675-1113

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