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hydraulic pressure testing

Discussion in 'Forklifts/Telehandlers' started by foolish, Aug 30, 2021.

  1. foolish

    foolish Well-Known Member

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    genie z34/22 platform lift and rotator problems. can you put pressure gauge directly to cylinder manifold or do you have to put a Tee into line and have all lines hooked up to get the correct hydraulic pressure?
    is it ok to use automatic transmission fluid in place of hydraulic fluid in a genie?
     
  2. Txhayseed

    Txhayseed Senior Member

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    You can test all your pressures on the test port on the manifold. All functions pull pressure and flow from the manifold directly. You could use atf if you wanted to sure... Several manufacturers use it in place of standard hydraulic fluid.
     
  3. foolish

    foolish Well-Known Member

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    thanks, i'll give it a try on the cylinder manifold. i wonder if i can use the bleeding locations on rotator for pressure test.
    thanks on the answer to atf, i was worried i may have ruin seals or something.
     
  4. Txhayseed

    Txhayseed Senior Member

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    You need to test pressures on the supplied pressure testing port, usually marked as pt1. You can tee in to lines if you wanted but the test port gives you the same info. I don't know how you would use the bleeder screw ports since its tapped for bolt thread and id be afraid if taking a gauge to the face when it lets loose.. Best to just use the test port... They put it there just for ya.
     
  5. foolish

    foolish Well-Known Member

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    i finally got to testing hydraulic pressure on the jib boom cylinder manifold. i only had 700# on tr port and 900# on te port.
    why would the pressure be so low? everything else works except platform rotator.
     
  6. Zewnten

    Zewnten Well-Known Member

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    Have you looked at the technical manuals Genie has on their website? Almost everything you need to know is in that manual, including troubleshooting. Make sure you pay attention to the serial number breaks.
     
  7. foolish

    foolish Well-Known Member

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    i have not found anything of help in the technical bulletins on genies website. but i will look more.
    thank you.
     
  8. Zewnten

    Zewnten Well-Known Member

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    Not the bulletins, although helpful. The actual manuals usually a couple hundred pages long. They'll help you diagnose almost anything.
     
  9. foolish

    foolish Well-Known Member

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    yes, i have the service manual. it has excellent trouble shooting flow charts. problem is that last steps say - repair or replace jib cylinder or replace jib counterbalance valves or platform rotate / jib function manifold. these are 100's of $. i would like to figure out which 1 before replacing if not needed.
     
  10. Zewnten

    Zewnten Well-Known Member

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    Just wanted to make sure, as they do have 2-3 page service bulletins as well. Unfortunately this is the gamble of doing work yourself. If the dealer is wrong, they should eat the cost of the part and sometimes they keep parts on hand for testing. Do you have an issue with the jib or just the platform?
     
  11. foolish

    foolish Well-Known Member

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    yes, that's for sure when i do stuff myself. and not always having the right tools and knowledge.
    i have posted several times with my problems on this genie.
    the jib boom will go up ok but then it immediately comes down, about 1 ft/sec. not sure if seal inside cylinder is bad or counterbalance valve, or ?
    the platform won't rotate either way. it did rotate some while bleeding it.
    machine is 2002 but only 270hrs on it.
    thank you
     
  12. Zewnten

    Zewnten Well-Known Member

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    I'd tee in with gauges on both ends of the cylinder, safely of course. Raise the jib and see what you get pressure wise. If no pressure change, it's bypassing internally in the cylinder.
     
  13. Delmer

    Delmer Senior Member

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    the jib cylinder could be leaking, move the jib up a little, then down and hold the valve in the down position for ten seconds, then immediately go and feel the cylinder, it should be warm where the piston is inside if it's leaking. If you can't feel the difference, try it again for twenty seconds, then feel the control valve also to see if that's turned warm also.

    You won't learn anything new by teeing into the lines to the cylinder, disconnect the line and cap it with the gauge. It won't build pressure if the cylinder is leaking. If the valve is good, the pressure will go up to the max system pressure with the line capped.

    The platform rotate not moving you could test by teeing to see what that says. Is that a hydraulic cylinder that rotates the platform?
     
  14. foolish

    foolish Well-Known Member

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    i tried lifting and then holding down toggle switch for the 10 and then the 20 sec. no change in temp. of cylinder or cylinder manifold. but temp. was 36 degrees this morning. so will try it again this afternoon.
    the jib cylinder has welded tubes from each end to the manifold so i can't tee in or cap it off.
    i only have 1 gauge so that's why i checked pressure separately at the cylinder manifold port or plugs , which are marked TR and TE and had the 700# and 900# pressure.
    the platform does have the rotator type cylinder. the auto store had trouble finding me connectors and tees from hydraulic lines to the gauge is pipe fitting. i have to go to the hydraulic places 100 miles away and get them.
    thank you
     
  15. Txhayseed

    Txhayseed Senior Member

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    What's your serial number so I can pull up your schematic. You will get different pressures between test ports due to relief valve settings. The jib/platform level circuit is on a separate hydraulic circuit along with the slave/compensation cylinder. The actually have a degree of acceptable drift. Your service manual should give you the drift allowance. If its not bad I wouldn't worry about it. When the machine is being used and functions are being used it should be a none issue unless you just feel like messing with it or its unsafe. Most booms will have a slight drift. You will not get the hydraulic system hot enough to use it for tangible diagnostics unless you have a serious issue. They do a very good job on keeping the hydraulic system in operating temp range by design. Have you tried moving the rotate function hoses over to another function port on the manifold. Swap a function over say like basket level up/down with your rotate function. If you stroke basket rotate and the function you swapped locations with work and the other function still does not get you basket to rotate then you narrowed it down to pretty much the rotator. Left rotate and right rotate both have a holding valve for each side. Its possible but not likely both would be faulty. You take all the variables out with a few steps by swapping functions over
     
  16. foolish

    foolish Well-Known Member

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    serial # 3415. this morning i disconnected the 4 outflow hoses from jib/platform manifold. moved toggles switch for jib cylinder and fluid flowed out each of its 2 hoses. same for rotator hoses . which appears nothing is plugged and solenoids work and valves work? then i put the 2 hoses for rotator in place of jib hoses and jib hoses in place for rotator.
    jib still raises but quickly comes right back down. the rotator rotated all the way to right when jib cylinder switch up but wouldn't move back to center or left with switch moved to lower.
    thank you