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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 (2) .
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| Illustration 2 | g00829280 |
Location of Pressure Tap for the Pilot System | |
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| Illustration 3 | g00787210 |
(1) Hydraulic oil sampling port. (2) Pressure tap for pilot system. (3) Pilot manifold. | |
- Attach the unconnected end of the hose assembly to a 8T-0856 Pressure Gauge (6000 kPa (870 psi)).
- 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 3450 ± 205 kPa (500 ± 30 psi).
- If the pressure is correct proceed to Step 15. If the pressure is incorrect proceed to Step 12.
- Loosen locknut (5) on pilot relief valve (4) .
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| Illustration 4 | g00787296 |
(3) Pilot manifold. (4) Pilot relief valve. (5) Locknut. (6) Setscrew. | |
- Turn setscrew (6) in order to adjust pressure to 3450 ± 200 kPa (500 ± 30 psi). Turn the setscrew clockwise in order to increase the pressure. Turn the setscrew counterclockwise in order to decrease the pressure.
- Tighten locknut (5) .
- Move the engine speed dial to position "1". Position "1" is low idle speed for the machine.
- Stop the engine.
- Close the cover on the step assembly.
- Remove the hydraulic test equipment.