Control Lever; Hydraulic System - Hitachi ZW 370-6 Operator's Manual

4. Control Lever

Symptom
Hard to move
Does not move smoothly
Does not return to neutral
The lever is tilted in the
neutral position due to
increase in play
The lever is not held with
magnetic detent.

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
Loader front and travel
functions are inoperable
(hydraulic pump noise level
increases).
All actuators have no power.
Only one actuator is
inoperable.
Only one cylinder is
inoperable or has no power.
Oil overheats
Oil leak from low pressure
hose
f
NOTE: * Consult the nearest authorized dealer.
TROUBLESHOOTING
Cause
Rusted joint
Worn pusher
Worn pusher
Faulty pilot valve
Faulty pilot valve
Worn joint
Faulty pilot valve
Faulty magnetic solenoid
Faulty sensor
Cause
Faulty hydraulic pump
Lack of hydraulic oil
Broken suction pipe and/or hose
Malfunction due to worn hydraulic pump
Decrease in set pressure of main relief valve in
control valve
Lack of hydraulic oil
Trapped foreign matter in hydraulic oil tank
suction filter
Aeration in suction side
Broken control valve spool
Trapped foreign matter in valve spool
Broken pipe and/or hose
Loose pipe line joint
Broken O-ring at pipe line joint
Broken actuator
Broken oil seal in cylinder
Oil leaf due to damage to cylinder rod
Clogged oil cooler
Faulty fan motor and pump
Weak tension of engine fan belt
Loose clamp
Faulty suction manifold
11-3
Solution
* Lubricate or repair
* Replace
* Repair or replace
* Replace
* Replace
* Repair or replace
* Replace
* Replace
* Replace
Solution
* Repair, Replace
Refill
* Repair, Replace
* Replace
* Clean, Adjust
Refill
Clean
Retighten
* Replace
* Repair, Replace
* Repair, Replace
Retighten
* Replace
* Repair, Replace
* Repair, Replace
* Repair, Replace
* Clean, Replace
* Repair, Replace
Adjust
Retighten
* Repair, Replace