| Required Tools | ||
| Part Number | Part Description | Qty |
| 177-7861 | Hose As | 1 |
| 6V-4143 | Coupler | 2 |
| 8T-0956 | Pressure Gauge (6000 kPa (870 psi)) | 1 |
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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 machine movement. Place blocks in front of and behind the wheels to make sure the machine does not move while the parking brakes are disengaged. |
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This test will show if the parking brake solenoid valves are operating correctly. This test will also show if the pilot oil pressure reducing valve is set to the correct pressure.
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| Illustration 1 | g01176840 |
Parking brake control valve (1) Parking brake pressure tap | |
- Remove the protective cover from pressure tap (1). Connect a hose assembly with an 8T-0856 Pressure Gauge 0 to 6000 kPa (0 to 870 psi) to pressure tap (1) on the parking brake control valve.
- Place blocks in front of the wheels and behind the wheels.
- Start the engine. Apply the service brakes.
- Disengage the parking brake by moving the parking brake switch to the OFF position.
- Observe the pressure gauge. The pressure reading on the gauge must be at the pilot oil pressure reducing valve setting. The pilot oil pressure reducing valve setting is 3620 ± 70 kPa (525 ± 10 psi).
- If the pressure reading on the gauge remains at 0 kPa (0 psi) when the parking brake is disengaged, check the operation of the parking brake solenoid valves and the electrical circuit for the parking brake.
- If the pressure reading on the gauge is not within the specification, check the pressure setting of the pilot oil pressure reducing valve.
Reference: Refer to Braking System, System Operation, Testing and Adjusting, "Pressure Reducing Valve (Pilot Hydraulic) - Test and Adjust".
- When this test is complete, release the service brakes, engage the parking brake and stop the engine. Remove the test equipment. Place the protective cover on the pressure tap.