Komatsu PC130-7, Shop Manual

Page: 49 / 342

PC130-7
20-131
TESTING AND ADJUSTING
TESTING AND ADJUSTING OIL PRESSURE
IN PUMP LS CONTROL CIRCUIT
2) Install nipple L2 and connect it to the oil
pressure gauge of hydraulic tester L1.
a
When using differential pressure gauge:
Connect the pump discharge pressure to
the high pressure side (back side) and
connect the LS pressure to the low pres-
sure side (lower side).
Since the differential pressure gauge
needs a 12-V power source, connect it to
a battery.
a
When using oil pressure gauge:
Use the oil pressure gauge of 58.8 MPa
{600 kg/cm
2
}.
Since the differential pressure is about
2.9 MPa {30 kg/cm
2
} at maximum, mea-
sure it by installing the same gauge to
the pickup plugs alternately.
3) Run the engine and heighten the hydraulic
oil temperature to 45 – 55°C, and then push
up the track shoe on either side with the work
equipment.
4) While running the engine at high idling, mea-
sure the pump discharge pressure and LS
valve output pressure (servo piston inlet
pressure) simultaneously.
•
Working mode: A
• Travel speed switch: Hi
• Work equipment, swing, and travel cir-
cuits:
Set all levers in neutral and run track
shoe on one side idle.
k
Checking the safety around the
machine, run the track shoe pushed up
idle.
a
Calculation of LS differential pressure
(when oil pressure gauge is used):
LS differential pressure = Pump dis-
charge pressure - LS pressure
a
If the LS differential pressure is as fol-
lows, it is normal.
5) After finishing measurement, remove the
measuring instruments and return the
removed parts.
Travel lever LS differential pressure
Neutral
LS differential pressure
in neutral
(See standard values
table)
Full (Idle running)
Specified LS differential
pressure
(See standard values
table)
(1)