Releasing Remaining Pressure From Hydraulic Circuit - Komatsu PC200-8M0 Shop Manual

SEN06127-00
Releasing remaining pressure
from hydraulic circuit
1. Releasing remaining pressure from hydrau-
lic tank
k
Since the hydraulic tank is enclosed
and pressurized, release the residual
pressure from it when removing a hose
or a plug connected to it.
1) Lower the work equipment to the ground
in a stable posture and stop the engine.
2) Loosen oil filler cap (1) of the hydraulic
tank gradually to release the air in the
tank.
2. Release of remaining
hydraulic cylinder circuit
k
When disconnecting a pipe between a
hydraulic cylinder and the control
valve, release the remaining pressure
from the piping according to the follow-
ing procedure.
1) Lower the work equipment to the ground
and release the residual pressure from the
hydraulic tank. For details, see "Releasing
remaining pressure from hydraulic tank".
a Keep the oil filler cap of the hydraulic
tank removed.
2) Turn the starting switch to ON position
and set the lock lever to the FREE posi-
tion, and then operate the right and left
work equipment control levers forward,
backward, to the right, and to the left.
a The control valve is operated by the
pressure in the accumulator. The
pressure in the accumulator is used
up, however, after the control valve is
operated 2 – 3 times.
3) Run the engine at low idle for 5 seconds to
increase the pressure in the accumulator.
a The engine does not start until the
lock lever is set to the LOCK position
once.
54
30-101

Releasing remaining pressure from hydraulic circuit

1
3.
4.
pressure from
101 Testing and adjusting, Part 1
4) Repeat steps 2) and 3) above 2 – 3 times,
and the residual pressure in the piping is
released completely.
Release of remaining pressure from swing
motor circuit
The remaining pressure in the swing motor cir-
cuit can be released by performing the opera-
tion for "Releasing remaining pressure from
hydraulic cylinder circuit" (Operate the lever to
SWING only, however).
Release of remaining pressure from travel
motor circuit
Since the control valve spool of the travel
motor circuit is connected to the drain circuit,
the pressure in this circuit can be released by
performing "Releasing remaining pressure
from hydraulic tank".
PC200, 200LC, 220, 220LC-8M0