OTC 5078 - Troubleshooting Guide; Bleeding Air from the Jack

Sheet No.
Issue Date: Rev D, Nov. 18, 2014
© Bosch Automotive Service Solutions LLC
3 of 3
Bleeding Air from the Jack
1. Retract the jack to its lowest position, and loosen the vented oil plug threaded into the top plate of the foot
pump reservoir.
2. Remove the plug (No. 15130, Item No. 1 in the cylinder assembly parts list) from the top of the packing
gland (No. 63340, Item No. 3).
3. Operate the foot pump until the main cylinder is full of oil.
4. Install the plug removed in Step 2.
5. Retract the jack to its lowest position.
6.Fillthefootpumpreservoirwithhydraulicjackoil(215SUSviscosityratingat100°F)tothecorrectuid
level (1/2" from the top).
7. Install the vented oil plug on the foot pump, and inspect for leaks.
Troubleshooting Guide
Repairproceduresmustbeperformedinadirt-freeenvironmentbyqualiedpersonnelwhoarefamiliarwith
this equipment.
Trouble Cause Solution
Unit fails to extend or extends 1.Lowuidlevel 1.Filltocorrectuidlevel.
partially
Incomplete or spongy cylinder 1.Lowuidlevel 1.Filltocorrectuidlevel.
response when foot pedal is 2. Air in system 2. Follow instructions to bleed air from system.
pumped
Abnormal leakage through 1.Lowuidlevel 1.Filltocorrectuidlevel.
unit breather
Unit fails to extend when foot 1. Release valve malfunction 1. Pump foot pedal with release valve open.
pedal is pumped 2. Contamination 2. Disassemble and clean unit.
3. Cylinder packing failure 3. Install repair kit.
Cylinder creeps 1. Load exceeds maximum 1. Reduce load.
lifting capacity
2. Release valve is leaking 2. Flush release valve by pumping foot pedal
with release valve open.
Cylinder doesn't retract when 1. Cylinder is binding 1. Disassemble unit; replace defective parts.
release pedal is activated
Cylinder doesn't extend 1. Contamination 1. Disassemble and clean unit.
2. Bad packing 2. Install repair kit.
Cylinder extends when foot pedal 1. Release valve malfunction 1. Flush release valve by pumping foot pedal
is pressed, and retracts as foot with release valve open.
pedal retracts 2. Contamination 2. Disassemble and clean unit.
Parts List & Operating Instructions Form No. 106329