Komatsu Galeo PC800-8, Shop Manual

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PC800, 850-8
21
30 Testing and adjusting
SEN00912-02
Release of residual pressure
from hydraulic circuit
1. Release of residual pressure from hydraulic
tank
k
The hydraulic tank is enclosed and pressu-
rized. When removing a hose or a plug con-
nected to the hydraulic tank, release the
residual pressure from the hydraulic tank
according to the following procedure.
1) Lower the work equipment to the ground in
a stable posture and stop the engine.
2) Slowly loosen oil filler cap (1) of the hydrau-
lic tank to release the air from the tank.
2. Release of residual pressure from hydraulic
cylinder circuit
k
When disconnecting the piping between a
hydraulic cylinder and the control valve, re-
lease the residual pressure from the piping
according to the following procedure.
1) Referring to 1. Release of residual pressure
from hydraulic tank, release the residual
pressure from the hydraulic tank.
a
Leave the oil filler cap of the hydraulic
tank removed.
2) Turn the starting switch to the ON position
and set the lock lever in the FREE position,
and then operate the work equipment con-
trol levers on both sides forward, backward,
to the right, and to the left to release resid-
ual pressure from the piping.
a
The control valve is driven with the pres-
sure in the accumulator. If it is operated
2 – 3 times, the pressure lowers.
3) Start the engine and run it at low idle for 5
seconds to heighten the pressure in the
accumulator.
4) Repeat above steps 2) and 3) 2 – 3 times,
and all residual pressure is released from
the piping.
3. Release of residual pressure from swing mo-
tor circuit
a
Release the residual pressure from the
swing motor circuit by performing the proce-
dure for 2. Release of residual pressure from
hydraulic cylinder circuit (Operate the left
control lever in only swing direction).
4. Release of residual pressure from travel mo-
tor circuit
a
Since the control valve spool of the travel
motor is open, release the residual pressure
from the travel motor circuit by performing
the procedure for 1. Release of residual
pressure from hydraulic tank.