Jackco Model 770 - Manual (Page 5)

TROUBLESHOOTING
Caution: To prevent personal injury, all inspection, maintenance, and repair
procedures must be performed when the jack is free of load.
Trouble Cause Solution
Jack dose not lift at all
1. No hydraulic oil. 1. Fill hydraulic oil.
2. Release valve opened. 2. Close release valve.
3. Defective suction valve and
delivery vavle. 3. Clean dust or sludge.
4. Defective packing. 4. Replace packing.
Jack lifts only partially
1. Lack of hydraulic oil. 1. Fill hydraulic oil.
2. Excess of hydraulic oil. 2. Drain out excess hydraulic oil.
Jack lifts load, but
doesn’t hold
1. Improper contact of suction
valve, delivery valve & by-pass
valve.
1. Clean and adjust all valves.
2. Worn out piston packing. 2. Replace piston packing.
Jack does not lower
1. Release valve blocked by foreign
material.
1. Clean release valve.
Poor lifting
1. Defective pump packings and/or
incorrect valving.
1. Clean release valve, replace
packings and hydraulic oil.
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