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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 |
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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 Dealer Service Tool Catalog" 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 steering system.
ReferenceFor the correct procedure to relieve any hydraulic oil pressure that may be in the steering system, refer to the Service Manual module for Testing and Adjusting, "Machine Preparation for Troubleshooting" for the machine that is being tested.
| Required Tools | |
| Part Number | Description |
| 198-4240 (1) | Digital Pressure Indicator |
| ( 1 ) | The 8T-0860 Pressure Gauge is also available. |
- Move steering frame lock (1) to the LOCKED position.
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| Illustration 1 | g00460133 |
Steering Frame Lock in the LOCKED Position (1) Steering frame lock. | |
- Engage the parking brake. Move the transmission direction selector to the NEUTRAL position.
- Attach a 0 to 25000 kPa (0 to 3600 psi) pressure gauge to pressure tap (2). Pressure tap (2) is located on the right side of the machine above the right neutralizer valve. Pressure tap (2) is also located on the right side of the signal pressure tap.
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| Illustration 2 | g01099999 |
Location of the remote pressure taps | |
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| Illustration 3 | g01193841 |
(2) Pressure tap for the steering pump pressure | |
- Start the engine. Operate the engine at high idle. Move the tilt control lever to the TILT BACK position in order to increase the temperature of the oil to normal operating temperature.
- After the oil has reached normal operating temperature, position the bucket and any attachments slightly off the ground. Run the engine at high idle.
- Turn the steering wheel to the FULLY TURNED position in order to obtain a reliable pressure reading.
Note: During the following step, do not keep the steering pump at stall condition for more than ten seconds. If necessary, release the steering wheel and wait for 30 seconds before you repeat the step.
- Record the pressure reading on the pressure gauge. The reading should be 20398 ± 797 kPa (2959 ± 116 psi).
- Adjust the pressure compensator valve if the steering system pressure is not correct.
- Stop the engine. Lower the bucket and any attachment to the ground.
- Remove the hydraulic line and the pressure gauge from pressure tap (2) .
Adjusting the Pressure Compensator Valve
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| Illustration 4 | g00460444 |
(3) Pressure and flow compensator valve (4) Adjustment screw for the pressure compensator | |
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| Illustration 5 | g00462907 |
(3) Top view of pressure and flow compensator valve (4) Adjustment screw for the pressure compensator (5) Pressure compensator spool (6) Spring (7) Locknut | |
- Remove the cover from the adjustment screw (4). Loosen locknut (7). Turn the adjustment screw (4) clockwise in order to increase the high pressure stall. Turn the adjustment screw (4) counterclockwise in order to decrease the high pressure stall. One turn of the adjustment screw equals approximately 2800 kPa (406 psi).
- After you turn the adjustment screw (4), tighten locknut (7) to a torque of 17 ± 3 N·m (150 ± 26 lb in).
- Replace the cover on adjustment screw (4) .