120
CYLINDER
7d
Troubleshooting
7d- 5.
7d-5-1. Cylinder - troubleshooting
No.
Symptom
Possible cause
Solution
1
Oil leakage
from Cylinder
head
1. Damage of the packing in the cylinder
Replace
2. Looseness of Cylinder head
Tighten
3. Damage on the rod
Repair, Replace
2
Oil leakage
from Cylinder
Comp.
1. Damage of the welded part
Repair
3
Drift is too
big
1. Damage of the packing in the cylinder
Replace
2. Damage inside of the cylinder tube
Repair, Replace
3. Oil leakage in the Control valve
Replace
4
Cylinder
vibrates
while
operation
1. Bend of the rod
Replace
2. Shortage of hydraulic oil in the tank
Replace
3. Sucking air from the fitting of the piping
Tighten
5
Operating
speed of the
cylinder is
slow.
1. Over - discharging of the battery
Charge
2. Lack of output of the pump
Replace
3. Plunger of the control valve does not work properly.
Inspect
4. Clogging of the filter in the tank
Clean or replace
5. Low relief pressure
Adjust
6. Damage of the packings of the piston
Replace
7. Hydraulic speed setting on the control system is not
proper.
Adjust
6
Lowering
speed is too
slow.
1. Stick of the spool in the flow control valve
Replace
2. Foreign article is caught in the flow control valve.
Clean
3. The spring in the flow control valve is damaged or
weakened.
Replace
4. Hose of the return circuit from the lift cylinder is
choked or bent.
Replace
7
Cylinder
does not
work.
1. Failure of the micro switch of the control valve
Replace
2. Failure of the wiring harness to the micro switch of
the control valve
Inspect and repair
3. Failure of the hydraulic contactor or the contact tip.
Inspect and repair
4. Blow out of the hydraulic main fuse.
Replace
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