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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. |
Note: The illustrations in the following procedure show the Water Delivery System installed on a 777F Off-Highway Truck.
| Required Tools | |||
|---|---|---|---|
| Tool | Part
Number |
Description | Qty |
| A | 8T-0860 | Pressure Gauges
|
1 |
| 6V-4144 | Quick Connect Couplers | 1 | |
| B | 177-7860 | Hose As | 1 |
| 6V-4142 | Fittings | 2 | |
| 6V-4143 | Quick Connect Couplers | 2 | |
| Optional Tools(1) | |||
|---|---|---|---|
| Tool | Part Number | Description | Qty |
| C(2) | 198-4234 | Pressure Gauge Tool Gp | 1 |
| D(2) | 198-4236 | Adapter Cable As | 2 |
| E(2) | 198-4238 | Pressure Sensor Gp
|
2 |
| (1) | The optional tools can be used to replace the analog pressure gauges in the required tool list. |
| (2) | Tool (C), Tool (D), and one Tool (E) are part of the 198-4240 Digital Pressure Indicator. |
- Drive the machine to a smooth, horizontal surface.
- Place blocks in front of the rear wheels and behind the rear wheels. Do not place blocks around the front wheels.
- Operate the engine at high idle.
- 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) . - Place the transmission gear selector in the PARK position.
- Operate the engine at low idle for a few minutes. Shut down the engine.
- Assemble Tool (A) and Tool (B). Connect Tool (A) to Tool (B).
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Illustration 1 g02774239 - Locate steering check and relief valve (2) on the machine frame behind the right front suspension cylinder.
- Install Tool (B) on pressure tap (1) for the steering system.
- 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. Check the pressure while you are holding the steering wheel against the steering cylinder stops. The pressure setting of the high-pressure cutoff valve is
20850 to 2243 kPa (3025 to 3197 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 16.
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Illustration 2 g02774292 - Locate high-pressure cutoff valve (5) on the steering pump.
Note: It may be necessary to lift the water tank for the machine in order to access these components. If the machine is equipped with a hoist system, consult the applicable Operation Manual. If the machine is not equipped with a hoist system, reference the technical literature of the tank manufacturer for recommendations on lifting the thank.
- Loosen locknut (4) of high-pressure cutoff valve (5).
- Use an Allen wrench to rotate setscrew (3) 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 (3) changes the pressure approximately
1310 kPa (190 psi) . - Tighten locknut (4).
- Go to Step 10 and retest. If the pressure is low, and if the pressure does not increase with this method, go to Step 21.
- Use the following steps in order to troubleshoot the system.
- Check the setting of the primary backup relief valve for the primary steering. Refer to "Relief Valve Primary Steering Backup - Test and Adjust."
- Check the setting of the pressure reducing valve in order to be sure that the primary steering oil is not leaking to the steering hydraulic tank.
- Check the seat of the secondary steering check valve in order to be sure that primary steering oil is not leaking into the secondary steering system.
- Check the seal of the primary steering pressure switch in order to be sure that primary steering oil is not leaking from the steering check and relief valve group.
- Remove the tooling.
- Drive the machine to a smooth, horizontal surface.
- Place blocks in front of the rear wheels and behind the rear wheels. Do not place blocks around the front wheels.
- Operate the engine at high idle.
- 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) . - Assemble Tool (A) and Tool (B). Connect Tool (A) to Tool (B).
- Install Tool (B) on pressure tap (1) for the steering system.
- Start the engine. Run the engine at low idle.
- Check pressure on Tool (A) without turning the steering wheel. The pressure setting of the flow compensator valve is
2000 to 3600 kPa (290 to 522 psi) . - 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 16. If the pressure is not within the specified range, go to Step 11.
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Illustration 3 g02774336 - Locate flow compensator valve (8) on the steering pump.
- Loosen locknut (6) of flow compensator valve (8).
- Use an Allen wrench to rotate setscrew (7) in order to adjust the pressure setting. Rotate setscrew clockwise in order to increase the pressure setting. Rotate setscrew counterclockwise in order to decrease the pressure setting.
Note: Each one quarter turn of setscrew changes the pressure approximately
414 kPa (60 psi) . - Tighten locknut (6).
- Go to Step 7 and retest.
Note: If the pressure cannot be adjusted, check the flow compensator valve. The spool may be sticking. Replace the entire pressure and flow compensator valve if the spool or the bore is damaged.
- Remove the tooling.
