SEN04114-06 30 Testing and adjusting
50 PC130-8
2. Releasing residual pressure from hydrau-
lic piping
When disconnecting a pipe between a hydrau-
lic cylinder and the control valve, release the
re
maining pressure from the piping according
to the following procedure.
Without anti-drop valve
1) Lower the work equipment to the ground
an
d release the remaining pressure in the
hydraulic tank. For details, see “Release
remaining pressure in hydraulic tank”.
a Leave the oil
filler cap of the hydraulic
tank removed.
2) Turn the starting switch to ON position, set
the wor
k equipment lock lever to FREE
position, and operate the right and left
work equipment control levers forward
and backward, and to the right and left.
a Th
e work equipment is operated by
the pressure in the accumulator.
Pressure in the accumulator is lost by
operating the work equipment 2 or 3
times.
3) Set the work equipment lock lever to
L
OCK position, start the engine, and run it
with the fuel control dial at MIN (Low idle)
position for approximately 5 seconds to
increase the pressure in the accumulator.
4) Repeat step 2 and 3 several times, and all
re
maining pressure is released from the
piping completely.
With anti-drop valve of boom
k Place the machine on a level ground.
1) Check the function of PPC accumulator
1] Retract arm cylinder and bucket cylin-
der to the stroke ends, and hold the
work equipment at height
(a) above
the ground.
a: 1.5 m
2] Keep the arm cylinder and bucket cyl-
inder retracted to the stroke ends,
turn the st
arting switch to OFF posi-
tion, and stop the engine.
3] Turn the starting switch to ON posi-
tion.
4] Set the work equipment lock lever in
F
REE position.
5] Check that the work equipment is
lo
wered to the ground by slowly oper-
ating the work equipment control
lever to the boom LOWER
direction
fully to the stroke end.
a If
the work equipment is lowered
under its weight to the ground,
the accumulator is normal.
a Pressure of accumulator drops
gradually after stopping the
engine. Be sure to perform this
Releasing residual pressure from
hydraulic circuit 1
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.
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