Testing and adjusting oil pressure
in pump LS control circuit 1
a Testing and adjusting tools for oil pressure in
pump LS control circuit
k Stop the machine on a level ground and
lower the work equipment to the ground.
Then, release the residual pressure from
the hydraulic circuit. For details, see
"Releasing residual pressure from hydrau-
lic circuit".
Testing
a Before testing the oil pressure in the LS control
circuit, check that the oil pressure in the work
equipment, swing, and travel circuits and the
basic pressure of the control circuit are normal.
a Test the oil pressure in the pump LS control cir-
cuit under the following condition.
q Hydraulic oil temperature: Within operating
range
1. Testing LS valve output pressure (servo
piston inlet pressure)
a Test the LS valve output pressure (servo
piston inlet pressure) and pump discharge
pressure simultaneously and compare
them.
1) Open the side cover of the pump room
and remove oil pressure pickup plugs (1)
and (2).
q (1): Pump discharge pressure pickup
plug
q (2): LS valve output pressure pickup
plug
2) Install nipple M3 and connect it to oil pres-
sure gauge [1] of hydraulic tester M1.
a Install nipple M3 to the inspection part
of plug (2) and connect it to oil pres-
sure gauge [1] by hose [2] of hydrau-
lic tester M1.
a Use the oil pressure gauges of 58.8
MPa {600 kg/cm
2
}.
3) Start the engine and push up the track
shoe on the side to be tested with the
work equipment and prepare for running
the track shoe idle.
k Since the raised track shoe will be
run idle during test, secure a suffi-
cient working area.
Symbol Part No. Part name
M
1
799-101-5002 Hydraulic tester
790-261-1204 Digital hydraulic tester
2 799-401-2701 Differential pressure gauge
3
799-101-5220 Nipple (10 × 1.25 mm)
07002-11023 O-ring
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