Testing And Adjusting Work Equipment Hydraulic Pressure - Komatsu WA250-6 Shop Manual

120 Testing and adjusting, Part 2

Testing and adjusting work equipment hydraulic pressure

Testing and adjusting work
equipment hydraulic pressure
Necessary tools
Symbol Part No.
799-101-5002
X
790-261-1204
T 793-463-1100
k
Loosen the oil filler cap slowly to release
the pressure inside the hydraulic tank, then
operate the control levers several times to
release the remaining pressure in the
hydraulic piping.
Measuring condition
Hydraulic oil temperature: 45 – 55°C
q
Measuring
1. Install hydraulic tester X (40 MPa {400 kg/cm
to the oil pressure measurement nipple.
2. Start the engine, raise the lift arm approx. 400
mm, run the engine at high idle, then operate
the control lever to tilt back the bucket, and
measure the pressure when the relief valve is
actuated.
WA250, 250PZ-6
Part Name
Analog type hydraulic tester
Digital type hydraulic tester
Stopper
Adjusting
1
a Always stop the engine before adjusting the oil
pressure.
k
When carrying out the operation with the
lift arm raised, set support [1] or lift arm
drop prevention stopper T in position
before starting the operation.
1. Remove front frame inspection cover (1).
})
2
2. Remove cap nut (2) of relief valve (5).
3. Loosen locknut (3) of relief valve (5), then turn
adjustment screw (4) to adjust.
a Turn the adjustment screw to adjust the
set pressure as follows.
TIGHTEN to INCREASE pressure
q
LOOSEN to DECREASE pressure
q
a Pressure adjustment for one turn of
adjustment screw: Approx. 2.43 MPa
{Approx. 24.8 kg/cm
a Do not carry out any adjustment if the
relief pressure cannot be measured accu-
rately.
4. After finishing the work, remove the measuring
instruments and return the removed parts.
SEN03837-01
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