777F, 777G, and 785D OEM Off-Highway Truck/Tractors Water Delivery System Caterpillar

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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.

Note: The illustrations in the following procedure show the Water Delivery System installed on a 777F Off-Highway Truck.

1. Drive the machine to a smooth, horizontal surface.

2. Place the transmission gear selector in the PARK position.

3. Apply the brakes. Place blocks in front of the rear wheels and behind the rear wheels. Do not place blocks around the front wheels.

4. Operate the engine at high idle.

5. 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) and 93 °C (200 °F).

6. Operate the engine at low idle for a few minutes. Shut down the engine.
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   Illustration 1	g02762517

7. Locate electric drive pump (1) on the machine frame beneath the engine compartment. Remove plug (2) from electric drive pump in order to provide access to the adjustment screw (not shown) for the main relief valve for the secondary steering system.

8. Rotate the adjustment screw clockwise three turns. This action will increase the pressure setting of the main relief valve for the secondary steering above the pressure setting of the backup relief valve for the secondary steering. Replace plug (2).

9. Assemble Tool (A) and Tool (B). Connect Tool (A) to Tool (B).
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   Illustration 2	g02762578

10. Locate steering check and relief valve (4) on the machine frame behind the right front suspension cylinder.

11. Install Tool (B) on pressure tap (3) for the steering system.

12. Start the engine. Operate the engine at low idle.

13. 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.

14. Rotate the steering wheel until the steering cylinder stop is reached. Continue turning the steering wheel against the stop.

15. Check pressure on Tool (A). The pressure setting of the backup relief valve for the secondary steering is 20700 ± 400 kPa (3002 ± 58 psi).

16. Release the steering wheel.

17. Place the transmission gear selector in the PARK position in order to apply the parking brakes.

18. Operate the engine at low idle for a few minutes. Shut down the engine.

19. If the pressure is within the specified range, go to Step 24. If the pressure is not within the specified range, go to Step 20.

20. Loosen locknut (7) on backup relief valve (5).

21. Use an Allen wrench to rotate setscrew (6) 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 1183 kPa (172 psi).

22. Tighten locknut (7).

23. Go to Step 12 and retest.

24. Adjust the pressure setting of the main relief valve for the secondary steering to the original pressure setting. Go to Testing and Adjusting, "Relief Valve (Secondary Steering Main) - Test and Adjust" for the correct procedure.

Circuit Fill and Prime Procedure

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Illustration 3	g03860067

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Illustration 4	g03860070
View (A-A)

1. Check the oil filter group to ensure tee (1) and test fitting (3) are installed. If installed, proceed to Step 4. If not installed, proceed to Step 2.

2. Remove the hose assembly from filter inlet (A). Install tee (1) to the inlet as shown.

3. Install one O-Ring seal (2) onto test fitting (3). Install the test fitting into tee (1). Install the hose assembly removed in Step 2.

4. Use quick disconnect coupler (5), and hose assembly (4) to connect filter cart group (6) to test fitting (3).

5. Fill the Water Delivery System (WDS) with Cat® HYDO Advanced 10 hydraulic oil.

6. Allow pressure in the hydraulic circuit to build. Hold the pressure until the WDS hydraulic tank is full. The approximate capacity of the tank is 33 L (8.7 US gal).

7. Remove quick connect coupler (5) from test fitting (3). Install one dust cap (7) onto test fitting (3).