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Diesel engine exhaust contains products of combustion which may cause personal injury. Always start and operate the engine in a well ventilated area, and, if in an enclosed area, vent the exhaust to the outside. |
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Personal injury can result from rotating and moving parts. Stay clear of all rotating and moving parts. Never attempt adjustments while the machine is moving or the engine is running unless otherwise specified. The machine must be parked on a level surface and the engine stopped. Attach a "Do Not Operate" or similar warning tag to the start switch and controls before servicing, repairing, or making adjustments to the machine. |
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Personal injury or death can result from sudden machine movement. Sudden movement of the machine can cause injury to persons on or near the machine. To prevent injury or death, make sure that the area around the machine is clear of personnel and obstructions before operating the machine. |
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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 attachments have been lowered, 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 machine. 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 in Caterpillar machines. Dispose of all fluids according to local regulations and mandates. |
| Required Tools | |||
|---|---|---|---|
| Tool | Part Number | Description | Qty |
| A | 8T-0860 | Pressure Gauge
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1 |
| 6V-4144 | Quick Connect Coupler | 1 | |
| B | 177-7860 | Hose As | 1 |
| 6V-4142 | Fitting | 2 | |
| 6V-4143 | Quick Connect Coupler | 2 | |
| C | 6V-3966 | Fitting As | 1 |
| D | 8J-7844 | Reducing Bushing | 1 |
| Optional Tools(1) | |||
|---|---|---|---|
| Tool | Part Number | Description | Qty |
| E(2) | 198-4234 | Digital Indicator | 1 |
| F(2) | 198-4236 | Adapter Cable As | 2 |
| G | 198-4238 | Pressure Sensor Gp
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1 |
| (1) | The optional tools can be used to replace the analog pressure gauges in the required tool list. |
| (2) | Tool (E), Tool (F), Tool (G) are part of the 198-4240 Digital Pressure Indicator Gp. |
Note: The illustrations in the following procedure show the Water Delivery System installed on a 777F Off-Highway Truck.
- Drive the machine to a smooth, horizontal surface.
- Place the transmission gear selector in the PARK position.
- Apply the brakes and shut down the engine.
- Turn the steering wheel several times in order to release any residual pressure from the steering hydraulic system.
- Place blocks in front of the rear wheels and behind the rear wheels.
- Push the button for the pressure release on the top of the breaker relief valve. The breaker relief valve is located on the top of the steering hydraulic tank.
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Illustration 1 g02764056 - Locate steering check and relief valve (1) on the machine frame behind the right front suspension cylinder. Remove steering pump oil pressure switch (2).
- Install Tool (D) at the location of steering pump oil pressure switch. Connect Tool (C) to Tool (D).
- Assemble Tool (A) and Tool (B). Connect Tool (A) to Tool (B).
- Connect Tool (B) to Tool (C).
- Start the engine. Run the engine at high idle.
- Place the transmission gear selector in the NEUTRAL position.
Note: When the transmission gear selector is in the PARK position, friction from the wheel brakes will not allow the secondary steering system to turn the wheels all the way to the cylinder stops.
- Turn the steering wheel to the right until the steering cylinder stop is reached. Continue turning the steering wheel against the stop. Hold the steering wheel in this position for 3 seconds and then release the steering wheel. Continue this step until the oil in the steering system reaches a temperature between
38 °C (100 °F) and93 °C (200 °F) . - Turn the steering wheel to the right until the steering cylinder stop is reached. Continue turning the steering wheel against the stop. Check the pressure while you are holding the steering wheel against the steering cylinder stops. The pressure setting of pressure reducing valve is
2600 + 500/-200 kPa (377 + 73/-29 psi) . - Place the transmission gear selector in the PARK position.
- Operate the engine at low idle for a few minutes. Shut down the engine.
- If the pressure is within the specified range, go to Step 22. If the pressure is not within the specified range, go to Step 18.
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Illustration 2 g02764079 - Loosen locknut (3) on the steering pressure reducing valve.
- Use an Allen wrench to rotate setscrew (4) in order to adjust the pressure setting. Rotate the setscrew clockwise in order to increase the pressure setting. Rotate the setscrew counterclockwise in order to decrease the pressure setting.
Note: Each one quarter turn of setscrew changes the pressure approximately
125 kPa (18 psi) . - Tighten locknut (3).
- Go to Step 11 and retest.
- Remove the tooling. Replace steering pump oil pressure switch (2).
