769D Off-Highway Truck: Pressure Reducing Valve (Steering) - Test

Table 1

Tools Needed	Qty
198-4240 Digital Pressure Indicator	1
198-4239 Pressure Sensor	1
8J-7844 Adapter Fitting	1
6V-3966 Valved Nipple Assembly	1

WARNING: Personal injury or death can occur if personnel are trapped between the wheel and the frame. The steering system is hydraulically controlled and wheels can crush personnel during movement.Use caution when working between the wheels and the frame. If the wheels must be turned, ensure that all personnel are clear of the machine before any movement.

(1) Steering check and relief valve (2) Steering pressure reducing valve(3) Steering pump oil pressure switch

(1) Steering pressure reducing valve (4) Locknut(5) Setscrew

1. Turn the steering wheel several times in order to release any residual pressure from the steering hydraulic system.

2. 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.

3. Remove steering pump oil pressure switch (3). Steering pump oil pressure switch is located behind the right front suspension cylinder on steering check and relief valve (1). Use a 8J-7844 Adapter Fitting and the 6V-3966 Valved Nipple Assembly in order to install a 198-4240 Digital Pressure Indicator with the198-4239 Pressure Sensor at the location of steering pump oil pressure switch (3) .

4. Operate the engine at HI IDLE. Turn the steering wheel to the right or turn the steering wheel to the left until the steering cylinder stop is reached. Then continue turning the steering wheel against the stop. Hold the steering wheel in this position for three seconds and then release the steering wheel. Continue this step until the oil in the steering system reaches at least 38 °C (100 °F).

5. Operate the engine at HI IDLE. Turn the steering wheel to the right or turn the steering wheel to the left until the steering cylinder stop is reached. Then, 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 (2) is 2600 + 500 - 200 kPa (377 + 73 - 29 psi).

6. If the pressure needs to be adjusted, stop the engine.

7. Loosen locknut (4) on steering pressure reducing valve (2) .

8. With an allen wrench, rotate setscrew (5) clockwise by 1/4 turn in order to raise the pressure. Rotate setscrew (5) counterclockwise by 1/4 turn in order to lower the pressure. Each 1/4 turn of setscrew (5) changes the pressure approximately 125 kPa (18 psi).

9. Repeat Steps 5 through 8 until the pressure setting is correct.

MARYGAR