Releasing Residual Pressure From Hydraulic Circuit; Releasing Residual Pressure From Swing Motor Circuit; Releasing Residual Pressure From Travel Motor Circuit - Komatsu PC210-8 Shop Manual

30 Testing and adjusting
Releasing residual pressure from
hydraulic circuit
1. Releasing residual pressure from hydraulic
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 position and stop the engine.
2) Loosen oil filler cap (1) of the hydraulic
tank gradually to release the air in the
tank.
2. Releasing residual pressure from hydraulic
cylinder circuit
k
When disconnecting a pipe between a
hydraulic cylinder and the control
valve, release the residual pressure
from the piping according to the follow-
ing procedure.
1) Lower the work equipment and release the
residual pressure from the hydraulic tank.
For details, see "Releasing residual pres-
sure from hydraulic tank".
a Keep the oil filler cap of the hydraulic
tank removed.
2) Turn the starting switch ON and set the
lock lever in the FREE position, 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
heighten the pressure in the accumulator.
a The engine does not start until the
lock lever is set in the LOCK position
once.
PC210, 230, 240-8
4) Repeat steps 2) and 3) above 2 – 3 times,
and the residual pressure in the piping is
1
released completely.
3. Releasing residual pressure from swing
motor circuit
The residual pressure in the swing motor cir-
cuit can be released by performing the opera-
tion for "Releasing residual pressure from
hydraulic cylinder circuit" (Operate the lever in
the swing direction only, however).
4. Releasing residual pressure from travel
motor circuit
Since the control valve spool of the travel
motor circuit is open, the pressure in this circuit
can be released by performing "Releasing
residual pressure from hydraulic tank".
UEN00228-04
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