VALVE GP-CONTROL 3893115 - Caterpillar

Test Preparation
Reference: For more information about preparing the machine for troubleshooting, refer to the Service Manual module Testing and Adjusting, "Machine Preparation for Troubleshooting" for the machine that is being serviced.Reference: Refer to the Service Manual module Testing and Adjusting, "System Pressure - Release".
Park the machine on a smooth, level surface. Move the machine away from other operating machines and away from personnel.
Permit only one operator on the machine. Keep all other personnel away from the machine or in sight of the operator.
Position the work tool on the ground.
Engage the parking brake.
Illustration 2 g03137299
Place the steering frame lock in the LOCKED position.
Release the hydraulic pressure. Test Procedure
Illustration 3 g02198436
Location of hydraulic service center
Illustration 4 g03665631
Location of steering pilot supply pressure tap (1) on the manifold (A) in the hitch (Right side view)
Illustration 5 g03665638
Location of implement/redundant steering pilot supply pressure tap (1a) in the hydraulic service center (C).
(1a) Implement/redundant steering pilot supply pressure tap
Illustration 6 g03666107
(1) Primary steering pilot supply pressure tap
(B) Manifold in hitch
Ensure that the engine start switch is in the OFF position. Install a 8T-0850 Pressure Gauge from 1U-5481 Pressure Gauge Group or a 198-4240 Digital Pressure Indicator to pressure tap (1).
Ensure that the engine start switch is in the OFF position. Install a 8T-0850 Pressure Gauge from 1U-5481 Pressure Gauge Group or a 198-4240 Digital Pressure Indicator to pressure tap (1a).
Start the engine and warm the hydraulic oil to a normal operating temperature of approximately 54 to 70°C (129 to 158°F).
Run the engine at low idle and the fan control at minimum fan speed.
Observe the pressure gauge from both gages.
The pressure reading should be at least 3500 345 kPa (500 50 psi).
If the pressure is correct, turn the engine start switch to the OFF position.
Release the hydraulic pressure. Refer to the Service Manual module Testing and Adjusting, "System Pressure - Release".
Remove the test equipment from the machine.
If the pilot oil pressure is not correct, turn the engine start switch to the OFF position. In order to adjust the pressure reducing valve, refer to the instructions below on adjusting the pressure reducing valve.Adjusting the Pressure Reducing Valve for the Steering Pilot Supply.
Illustration 7 g03665642
Control manifold located in hydraulic service center. Side removed for clarity.
(2) Pressure reducing valve for the primary steering pilot supply
Locate the pressure reducing valve for the primary steering pilot supply. The pressure reducing valve is located on the control manifold in the hydraulic service center.
Before adjusting the pressure reducing valve (2), release the hydraulic system pressure. Refer to Testing and Adjusting, "System Pressure - Release".
Ensure that the work tool is on the ground. Turn the engine start switch to the OFF position. Note: Always, turn adjustment screw clockwise in order to adjust the pressure. Turning clockwise will compensate for any internal friction inside the valve that would oppose the setting of the bias spring. For example, if