How To Bleed the Air from a Floor Jack

Floor jacks are useful in garages and workshops, as these let you lift vehicles from the ground to aid in doing repairs and checkups on the underchassis and suspension system. Floor jacks usually work through hydraulics, which can be efficient as long as the fluid pressure is adequate. However, in some cases, you might find that your hydraulic jack is no longer working efficiently. It might be slow in lifting up its load, and there might be a “slushy” feel to it, meaning it lifts, but not as efficiently and firmly as it is supposed to.

This might be a sign that there is air in the hydraulic system. You will need to bleed the air out of the hydraulics in order to regain that pressure as soon as you can. Operating a hydraulic lift with air in the system is also dangerous, because it can suddenly fail. This might lead to catastrophic results if the floor jack has a load on it, like a vehicle.

Bleeding your floor jack will require just a few simple tools. You will need a flathead screwdriver, or whichever screwdriver or wrench that corresponds to your jack’s pressure valve. You will also need your jack’s user’s manual, to verify where you can find the valve.

  • Raise the jack. First thing you need to do will be to raise the jack to its highest level. Ensure that the jack doesn’t have any load when you do this. Extend the jack up to the point where the ram piston (the part that holds up the load) is at its highest.
  • Release the pressure valve. Once you’ve raised the floor jack, locate the pressure valve and loosen it with your screwdriver or other appropriate tool. This can be done by turning the valve counterclockwise. A half-turn will usually suffice. At this point, the jack will lower itself.
  • Open the filler plug. Locate the floor jack’s filler plug and remove it with the flathead screwdriver. You can unscrew it by turning it counterclockwise until it is dislodged. There might be other plugs that might look the same, including check valves that should not be removed. Therefore, it’s very important that you know where the filler plug is. Consult your floor jack’s manual to be sure. As soon as the filler plug is removed, air should come out of the system. You will notice air hissing out, which is a sign that air is emptying out.
  • Replace the filler plug and repeat. Screw on the filler plug into its place. Tighten the pressure valve. After this, you will need to repeat the steps above until you can no longer hear any air hissing out of the filler plug.

Regularly check that your floor jack’s hydraulic system has no air. This will let it work more efficiently. This is also a safety measure, as removing air will ensure that the floor jack will not just suddenly fail. As an added safety measure, it’s always a good idea to use jack stands in place of floor jacks when working on the underside of your car for extended periods.


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