Maintaining small hydraulic jacks

topic posted Mon, July 11, 2011 - 9:34 AM by  Tanemon
You know, those "bottle jacks" as they sometimes are called... heavy-walled steel cylinders with a sliding shaft up the center. You see them in sizes (capacities) ranging from, say, 1.5 tons to 8 tons or more.

How do you maintain the fluid? And what kind of fluid do they use (oil, transmission fluid, or...?) I assume that since they have that wrench-accepting knob on the end of that threaded plug that that's where you add more fluid, if needed?

I got a lot of useful-looking odds and ends for a very cheap price from a guy who was moving away, and a 6-ton bottle jack was part of the deal. The honest-seeming guy said it worked (and the other stuff in the assortment was indeed in decent shape and has worked). But I turn the scre in, jack the handle, and still can't get the jack to lift at all. So I'm suspecting a low level of fluid.
posted by:
  • Unsu...

    Re: Maintaining small hydraulic jacks

    Mon, July 11, 2011 - 10:12 AM
    Most Bottle Jacks have a little pipe threaded plug on the side of the bottle you take that off turn it on it's side and fill till the hole spills fluid when the jack is right side up.

    Just think of it this way: When the fluid is too low it won't work. When it's low find any opening you can to get fluid in and add any common hydraulic jack oil sometimes labeled "pump oil." ( NOT BRAKE FLUID)

    If that doesn't fix the thing then you gotta take it apart and replace the o rings or V seals or Chevrons (different makers use different seals) . It's all really straight forward simple stuff. Once you open your first jack up you will be an expert and instantly qualified to do it as a vocation. They are all pretty much the same.

    • Re: Maintaining small hydraulic jacks

      Mon, July 11, 2011 - 10:35 AM
      Thanks, Cliff. That pretty much lays out the picture.

      Who sells "pump oil"? Auto-supply stores? Industrial-supply stores? And does "pump oil" have any other common names? (Like is it the same as hydraulic fluid used in tractor hydraulics?)
      • Unsu...

        Re: Maintaining small hydraulic jacks

        Tue, July 12, 2011 - 1:17 PM
        auto supply stores
        • Re: Maintaining small hydraulic jacks

          Tue, July 12, 2011 - 4:52 PM
          Okay. Well, this jack seems to have but one opening, that being the threaded plug that acts as the pressure-relief valve to let the jack down. So it's a pressure-on/pressure-off valve.

          I turned it out (unscrewed it), and I moved the handle to the "up" position - and at that point, it appears as if it will accept more oil. But I don't know how much. But I geuss, once I get the right pump oil, I'll try feeding some in - until it's as full as I can get it. Then put the plug back in.

          Nothing else to know, right?
  • Re: Maintaining small hydraulic jacks

    Mon, July 11, 2011 - 11:01 AM
    you may want to inspect the o-rings and seals too, if its been low on fluid for long
    tranny fluid or hydraulic oil are what it need, best bet is look it up online
    for specifics
    • Re: Maintaining small hydraulic jacks

      Wed, July 13, 2011 - 3:48 PM
      I've always had good luck calling the manufacturers for spare parts when quality products die on me. Hydraulic pistons are just about the easiest engineering project you can take on, once you have a bottle jack opened up it all makes sense.
      A couple of words of warning though, try to keep the hydraulic fluid off your skin if possible because it's really bad for you and can cause dermatitis and get fresh hydraulic fluid from an unopened bottle because it is hygroscopic and will absorb water which will degrade the ground finish on the piston and damage the seal much faster then it would ordinarily wear (this is more important on bigger jobs like the hydraulic ram on a tipping trailer (that takes some real pressure) or the brake lines of a vehicle.
  • Re: Maintaining small hydraulic jacks

    Sat, September 10, 2011 - 7:50 AM
    Does anyone know of an on-line site that illustrates the insides of a typical hydraulic bottle jack?

    I'd like to know how they work. I've never taken one apart, and a "survey" of my nieghbors hasn't turned up any body who has taken one apart. I might just dive in and open one up, but I'm a bit reluctant to without having at least seen an "exploded" or "x-ray" type illustration.

    Better yet, i wonder if there's some little on-line video about fixing bottle jacks? - but one hates to hope for too much! heh, heh
  • A
    offline 0

    Sat, September 10, 2011 - 10:03 AM
    Damn look what I just found:

    Basically everything you've always wanted to know about bottle jacks (with excellent graphics) - and then some.
    • Re:

      Mon, September 12, 2011 - 2:03 PM
      Thanks. That's got a lot of info. Helpful.
      • Re:

        Fri, September 16, 2011 - 2:44 PM
        A, above, kindly supplied a page with diagrams about how these bottle jacks are designed and how they work.

        For anyone else in my position, tring to get familiar and get proficient at maintaining and fixing them, here'e a valuable vid:
        Unfortunately, it's just a 'silent move' (has background music, no commentary). But you CAN learn lots from it. There are some companion vids, some by the same people, some by other people. They show up an the same Youtube page, so check them out, too.

        Put the vids together with the diagram A supplied, and you move forward!
        • Re:

          Mon, October 10, 2011 - 6:31 PM
          Today was leveling out a mobile home on blocks with an old American 10T jack, low on fluid due leaky seals. It was getting up not more than 2". Not wanting to drive clear to town for purpose-formulated jack oil, I used what was around. I had 2 kinds of motor oil, 2-stroke oil, and a few ounces of ATF. I trickled the ATF into the side filling hole. Lo & behold, the jack immediately was getting 4 to 6" lift of that 5 ton old trailer home with no drama.

          I reckon any heavier oil, even 90 or 120 weight TF will suit the need. Even used crankcase oil will do it I suspect, as the moving parts are neither at close tolerance nor run at high heat.
          • Re:

            Wed, October 12, 2011 - 5:35 PM
            I always use ATF for my jacks.
            I've been doing it for years, that type of oil is made to keep rubber seals as they should be. And after all , thats al there is to a hydro jack.

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