| REQUIRED TOOLS | ||
| Part Number | Description | Qty |
| 1U-5755 | Hose | 3 |
| 6V-4143 | Coupler Assemblies | 6 |
| 8T-0856 | Pressure Gauge 0 to 6000 kPa | 3 |
| 6V-3989 | Unvalved Nipple | 3 |
| 7X-2444 | Tee | 1 |
| 6V-3965 | Nipple | 1 |
| 6V-5049 | O-Ring Seal | 1 |
| 3J-1907 | O-Ring Seal | 1 |
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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 immediately by a doctor familiar with this type of injury. Always use a board or cardboard when checking for a leak. |
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| NOTICE |
|---|
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, NENG2500, "Caterpillar Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids on Caterpillar products. Dispose of all fluids according to local regulations and mandates. |
Before any tests are performed, prepare the machine for troubleshooting. Refer to Testing and Adjusting, "Machine Preparation". Before any tests are performed, visually inspect the machine for oil leaks and damaged parts. Refer to Testing and Adjusting, "Visual Inspection".
The pilot system pressure test determines the pressure to the pilot operated hydraulic controls. The pilot oil is supplied by the charge pump section of the gear pump.
- Engage the parking brake. Stop the engine.
- Block the wheels of the machine.
- Raise the cab. Refer to the Operation and Maintenance Manual, "Cab Support Operation".
- Install the 8T-0856 Pressure Gauges to the charge pressure tap (1) and to the speed sensing pressure tap (2) by using the 1U-5755 Hoses .
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| Illustration 1 | g00788454 |
(1) Charge pressure tap (2) Speed sensing pressure tap | |
- Install a 6V-3965 Nipple (5) to the end of supply line (3) by using the 7X-2444 Tee (4). Use a 6V-5049 O-Ring Seal when you install the tee. Use a 3J-1907 O-Ring Seal when you connect the nipple to the tee. The supply line is for the pilot operated hydraulic control ( work tool).
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| Illustration 2 | g00788464 |
(3) Supply line for the pilot operated hydraulic control ( work tool) (4) Tee (5) 6V-3965 Nipple for measuring the pilot pressure | |
- Install the free end of the remaining hose to the 6V-3965 Nipple that was installed into the tee. This pressure tap (5) is used to measure pilot pressure to the pilot operated hydraulic control ( work tool).
- Secure the three hydraulic lines so that the pressure gauges can be viewed by the operator during the test. The hoses should not be pinched when the cab is lowered.
- Lower the cab.
- Sit in the operator's seat. Fasten the seat belt and lower the armrest.
- Start the engine. Disengage the parking brake.
- Run the engine at low idle. Record the charge pressure and speed sensing pressure.
- Run the engine at high idle. Record the charge pressure, speed sensing pressure, and pilot pressure.
Show/hide table
Table 2 PILOT PRESSURES Pilot Pressure Low Idle High Idle Charge Pressure
3100 ± 200 kPa (450 ± 30 psi)
3300 ± 200 kPa (480 ± 30 psi)Speed Sensing Pressure
1100 ± 200 kPa (160 ± 30 psi)
2550 ± 100 kPa (370 ± 15 psi)Pilot Pressure for the Work Tool
3300 ± 200 kPa (480 ± 30 psi)Note: If the pilot pressure is not within specifications, refer to Testing and Adjusting, "Hydrostatic System - Test and Adjust".
- Reduce the engine to low idle. Stop the engine.
- Raise the cab. Remove the test equipment.
- Lower the cab. Refer to the Operation and Maintenance Manual, "Cab Support Operation". Remove the blocks.