BRACKET 1P1133 - Caterpillar

Illustration 1 g00833859
Main Control Valve (Two Function) (1) Main relief valve.
Illustration 2 g00833856
Main Control Valve (Three Function) (1) Main relief valve.Machine Preparation For Troubleshooting
Park the machine on a smooth, level surface. Park the machine away from working machines and personnel. Lower the work tools to the ground.
Allow only one operator on the machine. Keep all personnel away from the machine or in the view of the operator.
Engage the parking brake.
Illustration 3 g00914095
Place the steering frame lock in the LOCKED position.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.Testing The Main Relief Valve
Illustration 4 g00833877
(2) Pressure tap for the main hydraulics
Connect 1U-5481 Pressure Gauge Group and 1U-5482 Pressure Adapter Group to pressure tap (2). The pressure tap for the main control valve is located at the articulation hitch on the rear frame.
Start the engine. Enter the Implement Hydraulic Service Mode.Reference: For additional information about this mode, refer to the Troubleshooting Testing and Adjusting, "Implement Hydraulic Service Mode" for the machine that is being serviced.
Run the engine at high idle. Operate the control levers and move all the cylinders in order to increase the temperature of the hydraulic oil to normal operating temperature. Run the engine at low idle.
Raise the lift arms to the maximum height.
Position the lift lever in the full RAISE position. Increase the engine speed to high idle.
Hold the lift control lever in the full RAISE position. Observe the pressure gauge.Note: Do not keep the lift control lever in the full RAISE position for more than five seconds.
On a standard machine, the pressure setting of main relief valve (1) should be approximately 20700 340 kPa (3000 50 psi).
On a logging machine, the pressure setting of main relief valve (1) should be approximately 20700 340 kPa (3000 50 psi).Note: If the pressure setting of the main relief valve is not adjusted correctly, it will be necessary to adjust the main relief valve.
Run the engine at low idle. Lower the lift arms to the ground. Turn the key start switch to the OFF position. Proceed to the Section "Adjusting The Main Relief Valve".
If the main relief valve is adjusted correctly, ensure that the work tool is on the ground. Remove the test equipment.
Place the steering frame lock to the STORE position.Adjusting The Main Relief Valve
Illustration 5 g00298584
Loader Tower Access PanelLift arms are raised for photographic purposes only.
Ensure that the engine start switch is in the OFF position. Remove the loader tower access panel that is over the control valve in order to access the main relief valve.
Place the key start switch in the ON position. Do not start the engine. Move the control levers through the full range of travel several times. This will relieve any pressure that may be present in the implement hydraulic system. Place the key start switch in the OFF position.
Push the plunger on the breaker relief valve in order to relieve the pressure in