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OT. Bleeding a bottle jack

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  • OT. Bleeding a bottle jack

    Hello fellow machinists. I have a 12 ton bottle jack that has air in the system. It is full of jack oil but when I pump it there is clearly air in the system. It will move a little bit every few pumps of the handle but it will only go up about half way.

    Anybody have any ideas how to get the air out of it. I looked on google and one guy said to take the filler plug out and pump it fast for a about a dozen strokes but that didn't work.

    Thanks for any help with this.

    Brian
    OPEN EYES, OPEN EARS, OPEN MIND

    THINK HARDER

    BETTER TO HAVE TOOLS YOU DON'T NEED THAN TO NEED TOOLS YOU DON'T HAVE

    MY NAME IS BRIAN AND I AM A TOOLOHOLIC

  • #2
    With the bottle jack fully lowered and the release valve opened and in the down position, pump the jack about 15-20 times. This should expel the air. Sometimes you may have to repeat this procedure once or twice but it's always worked for me.

    Storing the jack by laying it on it's side is usually the biggest contributor to getting air in the system if everything else is good with the jack, (correct oil level and good seals).
    Home, down in the valley behind the Red Angus
    Bad Decisions Make Good Stories​

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    • #3
      Also make sure it's filled with oil or next time you jack it all the way up you're going to pump air back into it.

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      • #4
        I think I have had luck opening the release valve fully and then pulling the ram up by hand, then pushing it back down a few times.
        First thing I'd do, though, is change the fluid. It's amazing how changing the fluid can make problems vanish on small hydraulic devices.

        metalmagpie

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        • #5
          Willy has it right. See post #2.

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          • #6
            Thanks for the tips guys. I tried taking the fill plug out and pumping it fast one time yesterday but I'll try it again a few more times today and see if that takes all the air out.

            Brian
            OPEN EYES, OPEN EARS, OPEN MIND

            THINK HARDER

            BETTER TO HAVE TOOLS YOU DON'T NEED THAN TO NEED TOOLS YOU DON'T HAVE

            MY NAME IS BRIAN AND I AM A TOOLOHOLIC

            Comment


            • #7
              You don't need to take the fill plug out and you don't need to pump it fast. Not saying this is counter productive but I've never done it that way so not sure if this helps, hurts, or just doesn't make any difference at all.
              Home, down in the valley behind the Red Angus
              Bad Decisions Make Good Stories​

              Comment


              • #8
                I had the jack with me in our 5th wheel when we went through mountain regions. I wonder if that might be the reason it got air in it.
                OPEN EYES, OPEN EARS, OPEN MIND

                THINK HARDER

                BETTER TO HAVE TOOLS YOU DON'T NEED THAN TO NEED TOOLS YOU DON'T HAVE

                MY NAME IS BRIAN AND I AM A TOOLOHOLIC

                Comment


                • #9
                  Elevation changes should have no effect. As mentioned a jack designed to be used vertically and stored or placed horizontally well be susceptible to picking up air bubbles in the oil supply. The method described above merely allows the oil to be circulated and to release the air to where it should be.
                  Home, down in the valley behind the Red Angus
                  Bad Decisions Make Good Stories​

                  Comment


                  • #10
                    Originally posted by Willy View Post
                    You don't need to take the fill plug out and you don't need to pump it fast. Not saying this is counter productive but I've never done it that way so not sure if this helps, hurts, or just doesn't make any difference at all.
                    Pumping it slowly, particularly on the opening stroke, gives more time for the heavier fluid to move. Pumping with the valve open at first may also help expel air from the pump passages. If a trace amount of water got inside, or oxidation of the oil or other contaminants has allowed some rust or gum to slightly bind the check ball in place, 'carefully' banging the jack's base against a concrete driveway might even help. I also agree that if the oil is discolored or has particulates floating in it, it should be changed. The older jacks are fairly easily disassembled/reassembled for cleaning and replacing parts (most seals & O-rings are available).

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                    • #11
                      Originally posted by Willy View Post
                      Elevation changes should have no effect. As mentioned a jack designed to be used vertically and stored or placed horizontally well be susceptible to picking up air bubbles in the oil supply. The method described above merely allows the oil to be circulated and to release the air to where it should be.
                      Useful trick, if you have the jack apart, is a piece of silicone fish-tank-bubbler tube to the pump pickup port with a weight on the other end - the jack can then work in any position as the pickup will always be in the fluid (it may leak a bit from the reservoir's breather though - mine does...)

                      Dave H. (the other one)
                      Rules are for the obedience of fools, and the guidance of wise men.

                      Holbrook Model C Number 13 lathe, Testa 2U universal mill, bikes and tools

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                      • #12
                        Purging air from jack

                        To get air out of a bottle jack, pump it up as far as it will go, turn it up side down, open the valve and collapse the jack. Once is ususally enough.

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                        • #13
                          I finally go back out to the shop and tried pumping it several times with the valve open and also tried jacking it up and then turning it upside down and pushing the ram back in. When I did the upside down trick I could feel it just pushing air for the first inch or two and then slow down as it started pushing oil. Still no joy though.

                          I am thinking that maybe the O-ring on the pump is bad and it is sucking air when I pump it. Next time I'm out there I am going to take the pump apart and check the O-ring.

                          Thanks for the tips guys.

                          Brian
                          OPEN EYES, OPEN EARS, OPEN MIND

                          THINK HARDER

                          BETTER TO HAVE TOOLS YOU DON'T NEED THAN TO NEED TOOLS YOU DON'T HAVE

                          MY NAME IS BRIAN AND I AM A TOOLOHOLIC

                          Comment


                          • #14
                            I was not familiar with the inner workings of a hydraulic jack. Here is a diagram of the basic mechanism:

                            https://www.engineersedge.com/hydrau...aulic_jack.htm



                            And here is a fairly complete document on disassembly and repair:

                            http://www.rods-n-kustoms.com/tech/R...Floor-Jack.pdf
                            http://pauleschoen.com/pix/PM08_P76_P54.png
                            Paul , P S Technology, Inc. and MrTibbs
                            USA Maryland 21030

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                            • #15
                              Good information to save before I have a jack problem. Mike

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