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Personal injury or death can result from sudden machine movement. Sudden movement of the machine or release of oil pressure can cause injury to persons on or near the machine. To help prevent possible injury or death, refer to the information in Testing and Adjusting, "Machine Preparation for Troubleshooting". |
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Personal injury or death can result from escaping fluid under pressure. Escaping fluid under pressure, even a very small pin-hole size leak, can penetrate body tissue and cause serious injury and possible death. If fluid is injected into your skin, it must be treated by a doctor familiar with this type of injury. Always use a board or cardboard when checking for a leak. |
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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 product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, PERJ1017, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat® products. Dispose of all fluids according to local regulations and mandates. |
Reference: Refer to Braking System, Systems Operation, Testing and Adjusting, "Visual Inspection" when you begin to troubleshoot the problem.
Reference: Refer to Operation and Maintenance Manual, "Braking System - Test" for detailed operation checks for the brakes.
Problem: Service brakes do not apply correctly.
Probable Cause:
- Mud, rocks, or dirt under the brake pedal does not allow the service brake control valve to release to fully apply
- Wear or damage to the service brake control valve restricts the release of oil pressure from the service brakes
- Wear or damage to the retarder control valve restricts the release of oil pressure from the service brakes
- There is wear or damage to the brakes
Problem: Service brakes do not release correctly.
Probable Cause:
- There is no oil pressure to the inlet passage of the service brake control valve
- There is no gas charge in the hydraulic accumulator
- There is air in the oil for the brake hydraulic system
- Wear or damage to the service brake control valve restricts oil pressure to the service brakes
- Wear or damage to the retarder control allows leakage of pressure oil from the braking system
- Brake piston leakage exists
Probable Cause:
- The sensor for the retarder control is not operating correctly
- The retarder solenoid valve is not operating
- The Machine ECM is not operating correctly
- There is wear or damage to the brakes
Problem: The parking brake does not engage correctly.
Probable Cause:
- Wear or damage to the parking brake control valve allows leakage of oil pressure to the brakes
- The parking brake solenoid valve is not operating correctly
- There is wear or damage to the brakes springs
- There is wear or damage to the brakes
Problem: The parking brakes do not disengage correctly.
Probable Cause:
- There is no oil pressure to the inlet passage of the parking brake control valve
- There is no gas charge in the hydraulic accumulator
- There is air in the oil for the brake hydraulic system
- The parking brake solenoid valve is not operating because of an electrical fault
- Wear or damage to the parking brake solenoid
- There is wear or damage to the brakes
- Brake piston leakage exists
Problem: The service brakes are overheating.
Probable Cause:
- Excessive use of the service brakes on a grade
- Wear or damage to the service brake control valve allowing the release of oil pressure from the service brakes causing the brake to drag