Testing And Adjusting Oil Pressure In Pump Ls Control Circuit - Komatsu PC88MR-10 Shop Manual

30 Testing and adjusting
Hydraulic system

Testing and adjusting oil pressure in pump LS control circuit

00-A)
a Testing tools
Sym-
Part No.
bol
799-101-5002 Hydraulic tester
1
790-261-1205 Digital hydraulic tester
2 799-401-2701
P
799-101-5220 Nipple (10 x 1.25 mm)
3
07002-11023 O-ring
4 796T-440-1101 Sensor adapter
5 796T-440-1200 Sensor adapter
Place the machine on a level ground, lower
the work equipment to the ground, and
release the remaining pressure in the
hydraulic circuit. For details, see "Releasing
remaining pressure in hydraulic circuit".
Testing
(PC88MR-C2A4-362-K-00-A)
a Before testing the oil pressure in the pump LS
control circuit, check that the oil pressure in the
work equipment, swing, and travel circuits and
the source pressure of the control circuit are
proper.
a Check this item under the following conditions.
Hydraulic oil temperature: 45 to 55°C
Measuring LS valve output pressure (servo
piston inlet pressure)
a Check LS pressure (the load pressure of the
actuator) at the same time as the pump
discharged pressure, and calculate the
differential pressure.
1. Open the right side cover, and remove oil
pressure pickup plugs (1) and (2).
(1): Pump discharged pressure pickup port
(2): LS valve output pressure pickup plug
30-52
Part name
Differential pressure
gauge
2. Install nipple P3 to the test part of plug (1), and
connect them to oil pressure gauge [2] by using
hose of hydraulic tester P1.
a Use the oil pressure gauge of 60 MPa {600
kg/cm }.
2
3. Install nipple P3 to the test part of plug (2), and
connect them to oil pressure gauge [2] by using
hose of hydraulic tester P1.
a Use the oil pressure gauge of 60 MPa {600
kg/cm 2 }.
4. Start the engine, run the engine at high idle, set
the control levers in NEUTRAL, and measure
the oil pressure at the full stroke of bucket
CURL.
(PC88MR-C2A4-360-K-
PC88MR-10