81
Troubleshooting
7a- 4.
7a-4-1. Hydraulic pump - troubleshooting
No.
Symptom
Possible cause
Solution
1
No oil is
pumped
out.
1. Shortage of hydraulic oil
Replenish
2. Clogging of the suction hose or the suction filter
Inspect and clean
2
Oil leakage
1. Damage of the oil seal
Replace
2. Damage of the gasket (O-ring)
Replace
3. No good tightening or damage of the cover and the
body, or fitting surface is worn or damaged.
Retighten or
replace
3
Pressure is
not raised.
1. Wear of the bearing, gear and body
Replace
2. Mixture of air
l
Shortage of hydraulic oil
l
Air mixed from the suction hose connection
l
Damage of the seal kit (oil seal, O-ring)
Replenish
Retighten
Replace
3. No good adjustment of the relief pressure of the
control valve
Adjust
4
Abnormal
noise
1. Choked in the suction hose
Correct or replace
2. Clogging of the suction filter
Clean
3. Air mixed from the suction hose connection
Retighten
4. Air mixed from the oil seal
Replace
5. Air in the hydraulic oil
Withdraw air or
replace
6. Shortage of the hydraulic oil
Replenish
7. High temperature or viscosity of hydraulic oil
Replace
5
High oil
temperature
1. Contaminated oil
Replace
2. High viscosity of hydraulic oil
Replace
3. Overwork
Observe
specification
6
No rotation
of hydraulic
motor
1. Failure or no good adjustment of the valve
microswitch
Replace or Adjust
2. Blow out of the hydraulic fuse
Replace
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