| REQUIRED TOOLS | |||
| Item | Part Number | Description | Qty |
| A | 7X-2444 | Tee | 1 |
| B | 6V-3965 | Fitting As | 1 |
| C | 3J-1907 | O-Ring Seal | 1 |
| D | 6V-4143 | Coupler Assemblies | 6 |
| E | 6V-3014 | Hose | 3 |
| F | 6V-3989 | Unvalved Nipple | 3 |
| G | 8T-0856 | Pressure Gauge 0 to 6000 kPa | 3 |
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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 piston 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 one 7X-2444 Tee between the hydraulic hose which leads to the P1 port (1) and the P1 port (1). Install one 6V-3965 Nipple to the tee. Use a 3J-1907 O-Ring Seal when you connect the nipple to the tee.
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| Illustration 1 | g00726804 |
(1) P1 port for measuring pilot pressure (2) PS1 charge pressure tap | |
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| Illustration 2 | g00718349 |
(3) PS2 speed sensing pressure tap | |
- Install a 8T-0856 Pressure Gauge to the following test ports: P1 pilot pressure (1), PS1 test port (2) and PS2 test port (3). Use the 6V-3014 Hoses to install the gauges to the test ports.
- Secure the hydraulic lines so that the pressure gauges can be viewed by the operator during the test. Be sure to route the hoses so that the hoses will not be pinched when the cab is lowered.
- Lower the cab.
- Fasten the seat belt and lower the armrest.
- Start the engine.
- 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
2900 ± 100 kPa (420 ± 15 psi)
3300 ± 200 kPa (480 ± 30 psi)Speed Sensing Pressure
1100 ± 100 kPa (160 ± 15 psi)
2200 ± 100 kPa (320 ± 15 psi)Pilot Pressure
3300 ± 200 kPa (480 ± 30 psi)Note: If either 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.
- Remove the test equipment.
- Remove the blocks.