The following tools will be needed to do the procedure:
MEL1355 – Hydraulic Test Kit
Stop the engine.
Open the right side cover.
At the control valve assembly, find the pilot line (Item 1) [Figure 20-110-1] of the control lever (joystick) that is to be checked. (Boom, Arm, Slew, Bucket)
Disconnect the hydraulic hose (Item 1) [Figure 20-110-2] and fitting from the control valve.
From the test kit Install a 3447 kPa (35 bar) (500 psi) gauge (Item 1) [Figure 20-110-3] on the pilot line. Start the excavator, and warm the hydraulic oil to operating temperature.
Engage the circuit to be tested. Record the operating pressure.
The operating pressure should be approximately 2799 – 3103 kPa (28 – 31 bar) (406 – 450 psi).
If the operating pressure is correct, check the valve section spool for proper operation. If the operating pressure is incorrect, remove the pilot pressure relief valve, clean, install and retest. (See Testing And Adjusting The Pilot Pressure Relief Valve on Page 20-33-1.)
If the pressure is still incorrect replace the pilot pressure relief reducing valve. (See Testing And Adjusting The Pilot Pressure Relief Valve on Page 20-33-1.)