Hitachi ZW 550-6 User Manual

11-3
TROUBLESHOOTING
4. Control Lever
Problem Cause Solution
Hard to move Rusted joint * Lubricate or repair
Worn pusher * Replace
Does not move smoothly Worn pusher * Repair or replace
Faulty pilot valve * Replace
Does not return to neutral Faulty pilot valve * Replace
The lever is tilted in the neutral
position due to increase in play
Worn joint * Repair or replace
Faulty pilot valve * Replace
The lever is not held with
magnetic detent.
Faulty magnetic solenoid * Replace
Faulty sensor * Replace
5. Hydraulic System
After the machine has been kept stowed stored for a long
time, air in the oil may be separated and accumulate in
the upper section in the cylinder, causing slow response
time in operation or reducing cylinder power. In case these
symptoms appear, repeatedly operate all actuators several
times.
Problem Cause Solution
Loader front and travel
functions are inoperable
(hydraulic pump noise level
increases).
Faulty hydraulic pump * Repair, Replace
Lack of hydraulic oil Refill
Broken suction pipe and/or hose * Repair, Replace
All actuators have no power. Malfunction due to worn hydraulic pump * Replace
Decrease in set pressure of main relief valve in
control valve
* Clean, Adjust
Lack of hydraulic oil Refill
Trapped foreign matter in hydraulic oil tank
suction filter
Clean
Aeration in suction side Retighten
Only one actuator is inoperable. Broken control valve spool * Replace
Trapped foreign matter in valve spool * Repair, Replace
Broken pipe and/or hose * Repair, Replace
Loose pipe line joint Retighten
Broken O-ring at pipe line joint * Replace
Broken actuator * Repair, Replace
Only one cylinder is inoperable
or has no power.
Broken oil seal in cylinder * Repair, Replace
Oil leaf due to damage to cylinder rod * Repair, Replace
Oil overheats Clogged oil cooler * Clean, Replace
Slow fan speed * Repair, Replace motor and pump
Weak tension of engine fan belt Adjust
Oil leak from low pressure hose Loose clamp Retighten
Faulty suction manifold * Repair, Replace
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NOTE: * Consult the nearest authorized dealer.

Hitachi ZW 550-6 Specifications

General

Brand	Hitachi
Model	ZW 550-6
Category	Front End Loaders
Language	English