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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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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, PERJ1017, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat® products. Dispose of all fluids according to local regulations and mandates. |
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Do not turn the steering wheel when the engine is running and a low pressure gauge has been installed in the steering circuit. If the steering wheel is turned, the pressure of the oil to the steering cylinders will be too high for a low pressure gauge. |
| Steering System Pressure | |||
|---|---|---|---|
| Date | Equipment ID Code | ||
| Pressure Specification | Actual | ||
| Low Idle Margin Pressure | |
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| High Idle Steering Pump High-Pressure Cutoff | |
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This procedure is intended to test and adjust the steering system pressure.
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| Illustration 1 | g02591061 |
| Tool | Item | Part Number | Description | Qty |
|---|---|---|---|---|
| B | 198-4240 | Digital Pressure Indicator Gp | ||
| B1 | 198-4234 | Digital Indicator | 1 | |
| B2 | 198-4239 | Pressure Sensor Gp (0 to 41,369 kPa (0 to 6,000 psi)) | 2 | |
| B3 | 198-4236 | Adapter Cable As | 2 | |
- Move the machine to a smooth, horizontal location. Move the machine away from other operating machines and away from personnel. Place the transmission direction control switch in the NEUTRAL position. Engage the parking brake. Lower the bowl to the ground and lower the apron onto the bowl. Shut off the engine.
- Slowly loosen the filler cap for the hydraulic oil tank to release the pressure.
- Remove the dust cover from test port (2) and install sensor (B).
Remove the dust cover from test port (3) and install sensor (B).
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| Illustration 2 | g06550937 |
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(1) Steering control valve
(2) Test port for steering pump (3) Test port for the load sense line | |
- Start the engine and operate the engine at LOW IDLE. Do not turn the steering wheel.
- Check pressure from both sensors.
Subtract the load sense pressure from the steering pump discharge pressure to get the pump margin pressure.
The pump margin pressure should be
2100 ± 100 kPa (305 ± 14.5 psi) . - Release the parking brake and raise the bowl.
- Slowly steer the machine into the right steering stop.
- Increase the engine speed to high idle.
- Continue turning the wheel to the right as fast as possible into the steering stop. The pump discharge pressure should be
20500 ± 350 kPa (2975 ± 51 psi) . - Repeat Step 3 through Step 6 for a left-hand turn.
- Remove all test equipment. Install dust caps on test port (2) and test port (3).
- If the pressure reading is out of tolerance, stop the machine and shut off the engine. Loosen nut (6) and use adjustment screw (5) to change the steering pump high-pressure cutoff pressure. Turn the screw clockwise to increase the steering pump high-pressure cutoff. Turn the screw counterclockwise to decrease the steering pump high-pressure cutoff.
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| Illustration 3 | g06551664 |
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(4) Steering pump
(5) Adjustment screw (6) Nut | |