How to Replace Floor Jack O Rings

What You'll Need
Adjustable wrench
"O" ring kit
Hydraulic fluid

A floor jack is an invaluable tool in the garage. Working on a vehicle is much easier when you have a reliable jack in order to lift a section of the vehicle for working underneath. Like most tools, there is some maintenance that is needed in order to keep a floor jack in good working order. One of the common maintenance projects with a floor jack is to change the O rings when they begin to fail. With a few hours of your time and some simple tools you will be able to replace the O rings in your floor jack quite easily. 

Step 1 - Set Floor Jack on Solid Surface

Since floor jacks can be on the heavy side, you must find a stable work surface to work on. Position the floor jack on the work surface and make sure that you have plenty of room to work on it. 

Step 2 - Position Floor Jack on Table

In order to get at the "O" rings on the floor jack you will need to stand it up on one end where the set screw is facing the ceiling. Once it is held stable that way, turn the set screw in a counter clockwise direction until it is loose. 

Step 3 - Remove Set Screw

Continue to loosen the set screw on the back of the floor jack until you can remove it. Be careful removing the set screw and look at the inside of the jack to see if there is any fluid. 

Step 4 - Drain Fluid from Floor Jack

While you are changing the "O" ring of the floor jack you should replace the fluid. This will ensure that the fluid is clean without any dirt or debris in it. Tilt the floor jack until it starts to pour the fluid from the set screw hole into a drain pan. Once the fluid has been drained, stand the jack back into a vertical position. 

Step 5 - Fill Floor Jack with New Fluid

Hold a funnel directly onto the set screw hole and begin to pour new jack fluid into the body. Continue pouring the fluid until the level reaches just under the screw thread level. 

Step 6 - Replace the "O" Ring

Examine the control valve that you removed from the floor jack. If the "O" ring is completely deteriorated you might not be able to find it as it has broken apart. Clean off the groove for the "O" ring with rags and some compressed air. If the "O" ring is still in position, use a screwdriver to pry the ring off. Once the valve stem is clean, lubricate a new "O" ring with some fluid and slide it onto the valve stem until it seats in the right position. 

Step 7 - Replace Valve Stem

Set the stem back into the hole and screw it in a clockwise motion. Once it begins to get tight, lower the floor jack back onto its wheels. Use the floor jack handle and work the motion until it is raised to its full height. Release the jack and press the lifting arm down. Repeat this process a few times to make sure the fluid is working and the "O" ring is not leaking.