Why does my hydraulic jack not lift all the way up? (Please read details)?

When there is no weight on it, it will go all the way up. But, when i put even a little weight on it it only goes to about half or less. I tried opening the release valve and pumping it to bleed air, and i added hydraulic oil but it made no difference.

4 Answers

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  • Anonymous
    10 months ago

    Jacks wear out. I have just replaced my jack because it slowly allowed the car to sink down. Buy a new one. Safety is paramount with jacks.

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  • Anonymous
    10 months ago

    There is a pressure relief valve on the jack hand pump, if you try to overload it, the pressure relief valve will prevent the jack from lifting over it's capacity for safety. This must be a floor jack, as you increase the height on the lifting lever, it then compounds the weight on the hydraulic cylinder to a point and then pops the relief valve to bypass lifting fluid before the lifting lever "stress to breaking" point can be reached.

    If the jack won't lift, the pressure relief spring is broken in the hydraulic cylinder pump relief valve.

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  • marty
    Lv 7
    10 months ago

    You may have some bad seals which are preventing pressure to build. I've found with those it's easier to replace than fix.

    • mermeliz
      Lv 7
      10 months agoReport

      You can rebuild the jack using a rebuild kit for it, but the jacks are so affordable NEW that it isn't worth the effort to repair it. Harbor
      Freight has a good selection of jacks.

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  • 10 months ago

    Check the oil in the jack.

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