Komatsu PC130-7, Shop Manual, Page: 47 / 342

PC130-7
20-129
TESTING AND ADJUSTING
TESTING AND ADJUSTING
OIL PRESSURE IN PUMP LS
CONTROL CIRCUIT
a
Testing and adjusting instruments for oil pressure
in pump LS control circuit
MEASURING
1. Measuring LS valve output pressure (servo
piston inlet pressure)
a
Before measuring the LS valve output pres-
sure (servo piston inlet pressure), check that
the oil pressure in the work equipment,
swing, and travel circuits and the basic pres-
sure in the control circuit are normal.
a
Measure the LS valve output pressure (servo
piston inlet pressure) and pump discharge
pressure simultaneously and compare them.
k
Lower the work equipment to the ground
and stop the engine. Operate the control
levers several times to release the residual
pressure in the piping, and then loosen the
oil filler cap of the hydraulic tank slowly to
release the internal pressure of the hydrau-
lic tank.
1) Remove the top cover of the control valve
and open the pump room cover.
2) Remove oil pressure pickup plugs (1) and
(2).
•
(1): Pump discharge pressure pickup
plug (at top of control valve)
• (2): LS valve output pressure pickup
plug (at top of hydraulic pump)
3) Install nipple L2 and connect it to oil pressure
gauge [1] of hydraulic tester L1.
a
Use the oil pressure gauge of 58.8 MPa
{600 kg/cm
2
}.
• The drawing shows the pump discharge
pressure side.
• The drawing shows the LS valve output
pressure side.
Symbol Part No. Part name
L
1
799-101-5002 Hydraulic tester
790-261-1203 Digital hydraulic tester
2
799-101-5220 Nipple (10 x 1.25 mm)
07002-11023 O-ring
3 799-400-2701 Differential pressure gauge
(1)
TESTING AND ADJUSTING OIL PRESSURE
IN PUMP LS CONTROL CIRCUIT