Komatsu PC500LC-10R Shop Manual page 478

TEST AND ADJUST OIL PRESSURE IN WORK EQUIPMENT, SWING,
AND TRAVEL CIRCUITS
METHOD FOR ADJUSTING BOOM LOWER RELIEF PRESSURE (HIGH PRES-
SURE SET SIDE)
• When high pressure relief pressure for the boom LOWER
is not normal, adjust the high pressure side of the suction
safety valve (8) for boom LOWER.
• When high pressure relief pressure is generated, the pilot
pressure does not act on the selector port and the ma-
chine push-up switch is enabled.
1.
Disconnect the pilot hose (9).
2.
Loosen the lock nut (11) with the holder (10) fixed.
3.
Turn the holder (10) to adjust the pressure.
REMARK
• The pressure is increased as the holder (10) is turned
to the right. The pressure is decreased as it is turned to
the left.
• Quantity of pressure adjustment per turn of the holder
(10): Approx. 25.3 MPa {258 kg/cm
4.
Tighten the lock nut (11) with the holder (10) fixed.
3
Lock nut (11):
93 to 123 Nm {9.5 to 12.5 kgm}
5.
Connect the pilot hose (9).
After the adjustment, recheck the oil pressure according to the testing procedure previously described.
METHOD FOR ADJUSTING BOOM LOWER RELIEF PRESSURE (LOW PRES-
SURE SET SIDE)
• When the boom lower relief pressure (low pressure set
side) is not normal, or when the pressure on the high pres-
sure set side is adjusted, adjust the low pressure set side
of the suction safety valve (8) for boom LOWER according
to the following procedure.
• The machine push-up switch is turned off. The pilot pres-
sure acts on the selector port.
1.
Disconnect the pilot hose (9).
30-72
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30 TESTING AND ADJUSTING
PC500LC-10R