Method For Adjusting Oil Pressure In Pump Pc Control Circuit - Komatsu PC500LC-10R Shop Manual

TEST AND ADJUST OIL PRESSURE IN PUMP PC CONTROL CIRCUIT
4.
Install the nipple C, and connect the gauge A2 in the hy-
draulic tester A.
REMARK
Gauge in the digital hydraulic tester B can also be used in-
stead of the gauge A2.
5.
Start the engine.
6.
Select and display "Pre-defined Monitoring" (01/11) by re-
ferring to "SET AND OPERATE MACHINE MONITOR".
7.
Adjust the hydraulic oil temperature so that it is within the
specified range.
8.
Set the working mode to P ("Power Mode").
9.
Turn the fuel control dial to MAX (High idle) position.
10. Check that all control levers and control pedals are at
NEUTRAL position.
11. Test the oil pressure when the fuel control dial is at MAX
(High idle) and MIN (Low idle) positions.
See STANDARD VALUE TABLE, "STANDARD VALUE TA-
BLE FOR MACHINE" for standard values.
Remove the testing tools and restore the machine after the test is finished.

METHOD FOR ADJUSTING OIL PRESSURE IN PUMP PC CONTROL CIRCUIT

When the phenomena shown below occur and PC valves (7) and (8) seem to be defective, adjust them accord-
ing to the following procedure.
• As the working load increases, the engine speed drops largely.
• The engine speed is normal but the work equipment speed is low.
(7): Front pump PC valve
(8): Rear pump PC valve
NOTICE
The width across flats of PC valve lock nut is 13 mm, and
the width across flats (inside width) of adjustment screw is
4 mm.
Do not turn the other lock nuts and adjustment screws
since they affect the hydraulic pump performance.
1.
Put matchmarks on the end surface of the adjustment
screw (10).
Matchmarks are for these nus to be restored properly if the
restoration is necessary. (This is for the adjustment screw
to return to the original position for the time when turning it
in reverse)
2.
Loosen the lock nut (9).
3.
Rotate adjustment screw (10) clockwise or counterclock-
wise to adjust it.
30-78
30 TESTING AND ADJUSTING
PC500LC-10R