How to Troubleshoot Hydraulic Floor Jacks

Check the weight rating on the floor jack and the axle weight of the vehicle you're intending to lift with it. Axle weights can be found on a sticker in the driver's side door jamb. Remember that you're only lifting one axle at a time with a hydraulic floor jack, so combining the front and rear axle weights is not necessary. A two- or three-ton floor jack is capable of lifting almost all axles of any passenger vehicle or light-duty truck. Exceeding the weight limit will not only place stress on the floor jack, but will also be extremely unsafe.

Inspect the hydraulic floor jack before and after each use. Cracked welds, fluid leaks or damaged, loose or missing parts compromise the safety and effectiveness of the floor jack. Be sure to turn the jack on its side and inspect the ram in both the extended and retracted positions. Rusted or pockmarked ram pistons can cause the ram to fail, or to intermittently extend or retract the ram in jerky movements that can be unsafe.

Test the hydraulic jack before use by closing the release valve (turning the handle clockwise) and then pumping the handle to raise the hydraulic piston. The saddle should rise a few inches per pump. Lift the saddle as high as it will go, then turn the handle counterclockwise to disengage the release valve. The hydraulic fluid will purge back into the chamber and the saddle will lower all the way to the bottom. If the jack does not work properly going up or down, continue the troubleshooting procedures before attempting to lift anything with it.

Determine if the floor jack is not lifting properly or not lifting at all. This could be caused by not enough hydraulic oil in the reservoir or air trapped in the system. Refer to Step 5 to check and adjust the oil. To bleed trapped air, place the release valve in the fully retracted position (counterclockwise of the handle), remove the oil filler screw and pump the handle several times to purge the air from the system. Replace the oil fill screw and retest the floor jack.

Check the hydraulic oil level of the floor jack. Improper oil level of the jack will greatly decrease the effectiveness of the lifting power and proper lowering of the jack. Remove the oil fill plug and look into the chamber. The oil level should be between 3/16 to a 1/4 of an inch above the cylinder on most floor jack models. Refer to the owner's manual of your floor jack to ensure the level and measurement is correct. Use only a quality-grade hydraulic floor jack oil--do not use regular oil products. The correct amount of hydraulic oil will make certain that the ram can build the correct amount of pressure for both lifting and lowering. A funnel to add the oil will come in handy. Lubricate all moving parts with a premium lubricating oil. Clean the ram with an oily cloth to ensure that dust and dirt particles do not enter the hydraulic cylinder.

Place the saddle of the floor jack in a safe and secure lift point on the vehicle. Subframes or floor boards are not a secure location and will cave in under the weight of the axle, cause damage to the vehicle and compromise the safety of the hydraulic floor jack.

Close the release valve of the floor jack (by turning the handle clockwise) after the saddle has been placed properly. Pump the handle to extend the ram and lift the saddle. If the jack does not lift the load or begins to lower after it's lifted, check the tightness of the release valve. If the tightness of the handle and release valve is correct and then the jack still performs the same way, either a hydraulic malfunction has taken place on the jack or you're overloading the jack. In either case, do not use the floor jack. For a hydraulic malfunction, either have the floor jack inspected and fixed by a certified repair place or dispose of the jack and purchase a new one.

Lift the intended vehicle if the conditions mentioned in Step 6 do not occur. Always use a jack stand to support the vehicle and never the floor jack. The floor jack should be used to lift and lower the vehicle only. If you experience binding or a jerky motion from the retracting ram after removing the jack stand and lowering the floor jack, most likely the hydraulic oil is overfilled, or the ram is severely rusted or pockmarked. Too much oil in the reservoir will not allow the oil enough room to move back from the chamber, and the jack will bind or not move at all.