| NOTICE |
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Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the machine. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide", for tools and supplies suitable to collect and contain fluids in Caterpillar machines. Dispose of all fluids according to local regulations and mandates. |
This section provides probable causes to known problems. Since there may be several probable causes, specific inspections or instrument tests may be recommended. These inspections and tests will help to identify the causes that are most probable.
Note: Make sure that you use an oil with the correct viscosity for the operating conditions. To determine the correct oil viscosity, refer to Operation and Maintenance Manual, "Lubricant Viscosities" .
Problem List
Service Brakes
- The front service brakes do not operate and the warning system is not activated.
- The rear service brakes do not operate and the warning system is not activated.
- Service brakes slip and the warning system is not activated.
- The service brakes are not applied evenly.
- Too much force is needed in order to push the brake pedals and the warning system is not activated.
Parking Brake
- The parking brake does not hold the machine stationary.
- The parking brake does not engage when the parking brake control lever is actuated.
Service Brake Charging System
- The low oil pressure warning will not turn off.
Troubleshooting
Service Brake Problems
Problem 1: The front service brakes do not operate and the warning system is not activated.
Probable causes:
- The brake group within the axle housing is damaged.
- The lines to the front service brakes are obstructed.
- The front circuit of the service brake control valve is faulty.
Problem 2: The rear service brakes do not operate and the warning system is not activated.
Probable causes:
- The brake group within the axle housing is damaged.
- The lines to the rear service brakes are obstructed.
- The rear circuit of the service brake control valve is faulty.
Problem 3: The service brakes slip and the warning system is not activated.
Probable causes:
- The additives in the oil in one axle or in both axles are incorrect.
- The brake disc in the axle housing is worn.
Problem 4: The service brakes are not applied evenly.
Probable causes:
- The brake disc and associated components in the axle housing are excessively worn.
- The brake valve is sticking because of contaminated oil.
- The service brake valve is not delivering the correct amount of pressure.
Problem 5: Too much force is needed in order to push the brake pedal and the warning system is not activated.
Probable causes:
- The brake pedals and/or brake pedal linkages are damaged.
- The brake valve is sticking because of contaminated oil.
Parking Brake Problems
Problem 1: The parking brake does not hold the machine stationary.
Probable causes:
- The parking brake must be adjusted.
- The brake linings are too worn.
- There is grease or oil on the brake drum and/or on the brake lining.
Problem 2: The parking brake does not engage when the parking brake control lever is actuated.
Probable causes:
- The parking brake cable is disconnected.
- The parking brake cable has stretched until the cable will not actuate the parking brake.
- The parking brake is out of adjustment.
Service Brake Charging System Problems
Problem: The low oil pressure warning will not turn off.
Probable causes:
- There is inadequate pump pressure for the brake system.
Note: If you can turn off the warning by increasing the rpm of the engine, the cause of the problem is the brake pump.
- The hydraulic oil is too hot.