HARNESS AS 1458054 - Caterpillar

To adjust the line relief pressure, a temporary increased setting of signal relief valve for high pressure is required before any line relief valve can be adjusted. Turn the adjustment screw clockwise on signal relief valve for 1 FULL TURN. Refer to Testing and Adjusting, "Relief Valve (Signal) - Test and Adjust" for the temporary setting of the signal relief valve.
Illustration 5 g02179575
Line relief valve on the drift reduction valve for the boom cylinder head end
To adjust the boom lowering control valve line relief pressure, the line relief valve on the boom drift reduction valve must be turned all the way in.Note: This adjustment of the line relief valve on the boom drift reduction valve is a permanent adjustment.
Loosen the locknut on the line relief valve locate on the boom drift reduction valve.
Turn the adjustment screw clockwise on the line relief valve until the adjustment screw comes in contact with the stop. Do not tighten.
Tighten the locknut.
Start the engine.
Illustration 6 g01914649
Monitor and keypad (A) Engine speed (B) Gain/Response (C) AEC switch (D) Gain/Response switch
Place the machine controls at the following settings:
Engine speed dial "2"
AEC switch OFF
Gain/Response "CAT" (normal mode)Refer to Testing and Adjusting, "Engine Performance - Test (Engine Speed)" for engine rpm settings.
Place the hydraulic activation control lever in the UNLOCKED position.
Increase the hydraulic oil temperature to 55° 5°C (131° 9°F).Test Procedure
Set the engine speed dial to specification. Refer to Table 2.
Operate the implement joystick in the appropriate direction in order to relieve the valve.Note: A continuous relief of the valve for more than 10 seconds is not allowed.
Check the line relief valve pressure setting at pressure tap (1) or pressure tap (2). Refer to Table 2 for the pressure specifications of the line relief valves.
Return the joystick to the NEUTRAL position.Adjustment Procedure
Lowering Control Valve (Boom Cylinder Head End)
Illustration 7 g02174598
Line relief valve on the boom lowering control valve at the boom cylinder head endNote: In order to adjust the line relief valve on the right boom lowering control valve, the line relief valve on the left boom lowering control valve must be temporarily adjusted.
Mark the location of the adjustment screw on the relief valve on the left lowering control valve.
Loosen the locknut on the relief valve on the left boom lowering control valve. Turn the adjustment screw clockwise by one quarter turn. Tighten the locknut .
Move the joystick for the boom until the boom is at the full BOOM RAISE position (full extension of boom cylinders). Hold the joystick for the boom in this position.
Check the pressure in the boom cylinder head end on the pressure gauge at the pressure taps.
Return the joystick for the boom to the NEUTRAL position.
The pressure reading should be within the specification. Refer to Table 2. If the pressure reading at the pressure taps is not within the specification, adjust the line relief valve on the right boom lowering control valve.
In order to adjust the line relief valve on the right boom lowering control valve, loosen the locknut and turn the adjustment screw