CAT WDS OEM and 777F Off-Highway Truck/Tractor Water Delivery System Caterpillar


Relief Valve (Secondary Steering Main) - Test and Adjust

Usage:

777F JRP

------ WARNING! ------

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.


------ WARNING! ------

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.


------ WARNING! ------

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.


------ WARNING! ------

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.



NOTICE

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.


Table 1
Required Tools 
Tool  Part
Number 
Description  Qty 
8T-0860  Pressure Gauges
0 to 40000 kPa (0 to 5800 psi) 
6V-4144 Quick Connect Couplers 
177-7860  Hose As 
6V-4142 Fittings 
6V-4143 Quick Connect Couplers 

Table 2
Optional Tools(1) 
Tool  Part Number  Description  Qty 
C(2)  198-4234  Pressure Gauge Tool Gp 
D(2)  198-4236  Adapter Cable As 
E(2)  198-4239  Pressure Sensor Gp 
(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.

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.

  7. Assemble Tool (A) and Tool (B). Connect Tool (A) to Tool (B).


    Illustration 1g02763193

  8. Locate steering check and relief valve (2) on the machine frame behind the right front suspension cylinder.

  9. Install Tool (B) on pressure tap (1) for the steering system.

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

  11. 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.

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

  13. Check pressure on Tool (A). The pressure setting of the main relief valve for the secondary steering is 17225 ± 350 kPa (2498 ± 51 psi).

  14. Release the steering wheel.

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

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

  17. If the pressure is within the specified range, go to Step 21. If the pressure is not within the specified range, go to Step 18.


    Illustration 2g02763716

  18. Locate electric drive pump (3) on the machine frame beneath the engine compartment. Remove plug (4) 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.

  19. Use an Allen wrench to rotate adjustment screw in order to adjust the pressure setting. Rotate adjustment screw clockwise in order to increase the pressure setting. Rotate adjustment screw counterclockwise in order to decrease the pressure setting.

    Note: Each one quarter turn of setscrew changes the pressure approximately 1288 kPa (187 psi).

  20. Go to Step 10 and retest.

  21. Remove the tooling. Replace plug (4).

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