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Personal injury can result from hydraulic oil pressure and hot oil. Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system. Make sure all of the work tools have been lowered to the ground, and the oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand. |
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| 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 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. |
Note: Use the information in the reference to prepare the machine for this test. Also, use the information in the reference to relieve any hydraulic pressure that may be in the hydraulic system.
Reference: For the correct procedure to prepare the machine for this test, refer to Testing and Adjusting, "Machine Preparation for Troubleshooting" for the machine that is being serviced.
Reference: For the correct procedure to relieve any hydraulic oil pressure that may be in the hydraulic system, refer to Testing and Adjusting, "Hydraulic System Pressure - Release" for the machine that is being serviced.
| Required Tools | ||
| Part Number | Description | Qty |
| 8T-0856 | Pressure Gauge (0 to 870 psi) | 1 |
| 6V-3081 | Hose Assembly | 1 |
- Place the machine on level ground.
- Lower the felling head to the ground.
- Stop the engine.
- Open the cover for the engine compartment.
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| Illustration 1 | g00785429 |
Right Side of the Machine | |
- Attach a 6V-3081 Hose As to pressure tap (1) .
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| Illustration 2 | g00829277 |
Pilot Oil Filter (1) Pressure tap. | |
- Attach the open end of the hose assembly to a 8T-0856 Pressure Gauge (6000 kPa (870 psi)).
- Move the hydraulic activation control lever to the LOCKED position.
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| Illustration 3 | g00787225 |
Hydraulic Activation Control Lever | |
- Start the engine.
- Move the engine speed dial to position "10". This is high idle speed for the machine that is being serviced 2200 ± 80 RPM.
- Warm the hydraulic oil to normal operating temperature. Normal operating temperature is 55 ± 5°C (130 ± 10°F).
- Read the pressure gauge. The pressure should be 3250 to 3750 kPa (470 to 545 psi).
Note: This measurement is taken while the control valve for the hydraulic activation control lever is closed. Pilot oil does not reach any pilot control valves.
- Move the hydraulic activation control lever to the UNLOCKED position.
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| Illustration 4 | g00786054 |
Hydraulic Activation Control Lever | |
- Read the pressure gauge. the pressure should be 3250 to 3750 kPa (470 to 545 psi).
Note: This measurement is taken while the control valve for the hydraulic activation control lever is open. Pilot oil flows to all pilot control valves.
- Operate all the following functions on the machine.
- Boom
- Stick
- Tool tilt
- Swing
- Travel
- Felling head
- Boom
- If all the above functions are operating correctly the pilot system is working.
- Stop the engine.
- Remove the hydraulic test equipment.
- If the pressures do not meet the specifications above, follow the reference below for testing the pilot relief valve.
Reference: For additional information on testing the pilot relief valve, refer to Testing and Adjusting, "Relief Valve (Pilot) - Test and Adjust" for the machine that is being serviced.