Method For Adjusting Oil Pressure In Work Equipment, Swing, And Travel Circuits - Komatsu PC500LC-10R Shop Manual

30 TESTING AND ADJUSTING
METHOD FOR ADJUSTING OIL PRESSURE IN WORK EQUIPMENT, SWING, AND
TRAVEL CIRCUITS
METHOD FOR ADJUSTING UNLOAD PRESSURE
The unload valve (unload pressure) cannot be adjusted.
METHOD FOR ADJUSTING WORK EQUIPMENT AND TRAVEL RELIEF PRES-
SURE
If the work equipment and travel relief pressures are not nor-
mal, adjust the main relief valves (3) and (4) according to the
following procedure.
(3): Front main relief valve
(4): Rear main relief valve
• Remove the control valve upper cover before adjusting the
main relief valve on the front pump side.
• Adjust only the low relief pressure of the main relief valve.
(When the low relief pressure is adjusted, the high relief
pressure is set automatically.)
• When the low-pressure relief pressure is turned on, the 2-stage relief solenoid valve is OFF, and thus the
pilot pressure is not applied to the selector port.
1.
Disconnect the pilot hose (5).
The figure shows the front main relief valve.
2.
Loosen the lock nut (7) with the holder (6) fixed.
3.
Turn the holder (6) to adjust the pressure.
REMARK
• The pressure is increased as the holder (6) is turned to
the right. The pressure is decreased as it is turned to
the left.
• Quantity of pressure adjustment per turn of holder (6):
Approx. 20.5 MPa {209 kg/cm
4.
Tighten the lock nut (7) with the holder (6) fixed.
3
Lock nut (7):
49 to 58.8 Nm {5 to 6 kgm}
5.
Connect the pilot hose (5).
After the adjustment, recheck the oil pressure according to the testing procedure previously described.
PC500LC-10R
TEST AND ADJUST OIL PRESSURE IN WORK EQUIPMENT, SWING,
2
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AND TRAVEL CIRCUITS
30-71