Hitachi ZW 550-6, Operator'S Manual

Page: 335 / 438

MAINTENANCE
7-51
Check Pilot Circuit Accumulator Function, Gas
Leakage, Looseness, and Damage
--- every 2000 hours
f
NOTE: The loading pilot pressure is supplied from the
accumulators in the brake circuit.
d
WARNING: Allow only qualified personnel to
handle the accumulator.

High-pressure nitrogen gas is enclosed in the
accumulator. (N
2
is inert.)

Never strike the accumulator. Keep the
accumulator away from heat sources.

Do not weld the accumulator housing.

Be sure to release oil pressure before starting to
work on pilot circuits.
1. Park the machine following the same procedures as
described on page 7-6 for preparation of inspection/
maintenance work.
2. Raise the lift arm at the maximum height, and
then set the lift arm control lever in the Neutral (N)
position.
3. Turn the key switch OFF to stop the engine.
4. Turn the key switch to ON position. (Do not start the
engine.)
5. Confirm the safety around the machine.
6. Place the lift arm control lever to FLOAT position (C)
and lower the bucket 1 m (3 ft) off the ground within
2 minutes after stopping the engine.
7. Place the lift arm control lever to the LOWER position
(B) and lower the bucket the rest of the way to the
ground.
8. Ensure the lift arm does not stop halfway. If the lift
arm stops halfway, the accumulator function may be
deteriorated. Consult your nearest authorized dealer
for check and repair.
E
N
D
B
N
A
C
115Z7-1-92-1
C
B E
N N
A
F G
D
M4GB-01-072
115Z7B-1-142-4