© SPX Corporation
Parts List & Operating Instructions
Form No. 106218
Preventive Maintenance
Important: The greatest single cause of failure in hydraulic units is dirt. Keep the under axle jack clean and well lubricated to prevent
foreign matter from entering the system. If the jack has been exposed to rain, snow, sand, or grit, it must be cleaned before it is used.
1. Store the jack in a well-protected area where it will not be exposed to corrosive vapors, abrasive dust, or any other harmful elements.
2. Regularly lubricate the moving parts.
3. Replace the oil in the reservoir at least once per year. To check the oil level, disconnect the air supply, place the under axle jack on
level ground, and completely retract the ram. Remove the plastic cover and plug from the oil filler hole. The oil level should be within
1/4" of the filler plug hole. If necessary, add approved anti-wear hydraulic jack oil, and install the filler plug again. Important: The use
of alcohol, hydraulic brake fluid, detergent motor oil, or transmission oil could damage the seals and result in jack failure.
4. Inspect the jack before each use. Take corrective action if any of the following problems are found:
a. Cracked or damaged housing
d. Scored or damaged piston rod
b. Excessive wear, bending, or other damage
e. Loose hardware
c. Leaking hydraulic fluid
f. Modified or altered equipment
Troubleshooting Guide
Repair procedures must be performed in a dirt-free environment by qualified personnel who are familiar with this equipment.
Trouble
Cause
Solution
Erratic action
1. Air in system
1. To bleed air, place jack on its base with
ram retracted, open release valve knob,
and cycle ram 20 times.
2. Oil viscosity too high
2. Change to a lower viscosity oil
3. Internal leakage in cylinder
3. Replace worn packings. Look for
excessive contamination or wear.
4. Cylinder sticking or binding
4. Look for dirt, gummy deposits, or leaks.
Check for misalignment, worn parts,
or defective packings.
Jack does not lift
1. Release valve is open
1. Close release valve
2. Low/no oil in reservoir
2. Fill with oil and bleed system
3. Air-locked system
3. Bleed system
4. Load is above capacity of jack
4. Use correct equipment
5. Delivery valve and/or bypass
5. Clean to remove dirt or foreign matter.
valve not working correctly
Replace oil.
6. Packing worn out or defective
6. Replace power unit
Jack lifts only partially
1. Too much or not enough oil
1. Check oil level
Jack advances slowly
1. Pump not working correctly
1. Replace power unit
2. Leaking seals
2. Replace power unit or seals
3. Low air pressure
3. Adjust air pressure to 90 - 200 psi.
Jack lifts load, but doesn’t hold
1. Cylinder packing is leaking
1. Replace power unit or seals
2. Valve not working correctly (suction,
2. Inspect valves. Clean and repair
delivery, release, or bypass)
seat surfaces.
3. Air-locked system
3. Bleed system
Jack leaks oil
1. Worn or damaged seals
1. Replace power unit or seals
Jack will not retract
1. Release valve is closed
1. Open or clean release valve
Jack retracts slowly
1. Cylinder damaged internally
1. Send jack to OTC authorized service
center for repair
2. Link section is binding
2. Lubricate link section
Sheet No.
4 of 4
Issue Date:
Rev. C, 8-16-02
