Fix It

Extend the jack arm fully to its maximum height at the jack mount surface.

Locate the release valve on the opposite side of your pump. Pull out the piston located within the chamber.

Use your flashlight to check the chamber for cracks, oil build-up, dirt and other substances. You should see a small trace amount of oil within the chamber but nothing more. Excessive dirt indicates a bad seal which will require professional repair.

Locate the oil reservoir filler cap which is the uppermost cap inside the release valve. Use your screwdriver to pry open the cap if necessary. The hydraulic oil should be 1/4 inch below the opening. Fill the reservoir to the 1/4 inch mark if necessary.

Wipe the jack clean with a cloth to detect oil. Pump the jack several times by the handle with the release valve still open. Look for leaking oil.

Close the release valve. Pump the jack up to its full height position. If the jack will not rise, bleed the jack by opening the release valve.

Attach the jack to your vehicle. Pump the jack to lift the vehicle to see if the jack is now working properly. If the jack will not lift, seek professional repair.

Assemble the piston. Both parts of the piston are long thin tubes. Generally, the two tubes will slide inside one another. One more piece will screw into the top of the piston to support the car --- although depending on your jack you may need to install this between Steps 2 and 3. While you are assembling the piston check the seals on both the inner and outer parts of the piston for cracks, pinches or breaks. Replace any damaged seals before installing the piston in the case.

Place the piston assembly inside the jacks case through the large hole in the top. Secure the piston in place by using the tank nut. This is a large nut that screws into the top of the case and holds the piston in place. Unless you have a very small jack you will need to secure this in place with a pipe wrench.

If you were unable to install the top of the piston to support the car, then you should do so now.

Find two small ball bearing-sized balls and two springs. One ball and spring should be slightly larger than the other. Locate the overload valve on the bottom of the casing of the jack. if you look down this hole you will see a two-tiered hole. The bottom tier will be larger than the small ball but smaller than the large ball. Drop the small ball and spring in first, followed by the larger ball and spring. Cover the hole with a screw or bolt to seal it.

Locate the hole for the release valve. This is a hole with a small gap or pin at the bottom. On some jacks you will install the cap so it touches the pin and on others there will be a small ball that sits between them to press the pin. Drop the ball in and screw the cap into place.

Stand the jack upright and locate a hole for the pump piston. This is either in the base in a floor jack or offset to one side in a bottle jack. Examine the o-rings and washers on the inside to make sure they are in good condition and then push the piston into place. Nothing holds the piston in the hole so there are no bolts to install.

Attach the handle to the top of the pump piston. This is done with a bolt or pin that connects a hole at the top of the piston to a circular holder for the handle. Attach the handle to the pivot point, again using a pin or bolt depending on the model. You may also find there are some other attachments for the handle assembly on the base of the jack.

Fill the jack with hydraulic oil by opening the oil reservoir cap and filling it until the oil level is about 1/4-inch below the level of the hole when the jack is lying on its side. Bleed any air from the system by opening the release valve and pumping the handle vigorously several times. Raise the jack to its full extent and then lower it normally. Repeat the pumping, raising and lowering process until the jack is extending to its full height every time.

Wipe the jack clean and test it by lifting a vehicle. Lower the vehicle again and check around the jack for any leaks of fluid. Check the fluid level again to make sure it has not dropped.