USAG 2510 C, Original Instructions Manual

4 

PREVENTIVE MAINTENANCE

Important: The greatest single cause of failure in hydraulic units is dirt. Keep the service 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 lubrificate the moving parts in the wheels, arm, handle, and pump roller pin.
3. Replace the hydraulic fluid in the reservoir at least once per year. To check the hydraulic fluid level, lower the lifting arm completely. Remove the rubber 
filler plug from the power unit. The hydraulic fluid level shoulb be at the bottom of the filler plug hole. If necessary, add hydraulic fluid and install the filler plug. 

IMPORTANT : the use of alcohol or hydraulic brake fluid 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, damaged housing  

e. Loose hardware

b. Excessive wear, bending, or other damage   

f. Modified or altered equipment

c. Leaking hydraulic fluid   

d. Scored, damaged piston rod

5. Keep warning labels and instructional decals clean and readable. Use a mild soap solution to wash external surfaces of the jack.

5 

TROUBLESHOOTING GUIDE

Repair procedures must be performed in a dirt-free environment by qualified personnel who are familiar with this equipment.

CAUTION : To prevent personal injury, all inspection, maintenance, and repair procedures must be performed when the jack is free of a load (not in 
use).

Trouble

Cause

Solution

Jack does not lift

1 . Release valve is open.

2. Law/no hydraulic fluid in reservoir. 
3. Air locked system.
4. Load is above capacity of jack.
5. Delivery valve and/or bypass valve not 
working correctly.
6. Packing wom out or defective.

1. Verify the release valve is closed by position of the handle. Release 
valve may need cleaning.
2. Fill with approved hydraulic fluid & bleed system.
3. Bleed the system.
4. Use correct equipment.
5. Clean the remove dirt or foreign matter. Replace hydraulic fluid.

6. Replace packing.

Jack lifts only partially

1. Too much or not enough hydraulic fluid.

1. Check hydraulic fluid level.

Jack advances slowly

1. Pump not working correctly. 
2. Leaking seals.

1. Rework pump.
2. Replace seals.

Jack lifts load, but doesn't hold 1. Cylinder packing is leaking.

2. Valve not working correctly (suction, delivery, 
release, or bypass.
3. Air-locked system.

1. Replace packing.
2. Inspect valves. Replace if necessary.

3. Bleed system.

Jack leaks hydraulic fluid

1. Wom or damaged seals.

1. Replace seals. 

Jack will not retract

1. Release valve is closed.

1. Open the release valve by pulling on and turning the handle 
clockwise. May be necessary to clean reverse valve.

Jack retracts slowly

1. Cylinder damaged internally.
2. Return spring(s) is damaged.
3. Link section is binding. 

1. Send jack to authorized service center.
2. Replace return spring(s).
3. Lubricate link sections.