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What's the best way to bleed a lift cylinder?

Discussion in 'Fisher Engineering Discussion' started by wildbl1500, Dec 4, 2008.

  1. wildbl1500

    wildbl1500 Senior Member
    Messages: 111

    Ok, I'm pretty sure my lift cylinder is air-bound. I see all over the place that for angled rams you just work them back and forth and they bleed themselves. But, how about the lift cylinder? On my setup, maybe on all MM2s, my lift cylinder hose is routed up out of the manifold and then back down to the cylinder. I would assume that if air is trapped at highest point, the the bend in the hose, it isn't going to bleed itself back into the resevoir...

    Any suggestions? I'm a novice at hydraulic systems!:confused:
  2. wildbl1500

    wildbl1500 Senior Member
    Messages: 111

    ok, so I am an idiot.

    My issue wasn't air in the lift cylinder line- there may have been some, but that wasn't the issue. I found out today that relief valves are very, very sensitive... I apparently tightened the lift cylinder's relief valve too much- even though it was on the high end of the suggested range. It wasn't liking the weight of the blade...
  3. Blasco

    Blasco Junior Member
    Messages: 16

    Maybe unpin the cylinder and tip it down?
  4. wildbl1500

    wildbl1500 Senior Member
    Messages: 111

    I don't think that would have worked, due to the 90 degree fitting coming out of the manifold. If I turned that over and pulled the upper pin, it probably would work... All I did was crack open the fitting on the lift cylinder and run the pump... The other way that may have worked (in my mind, anyway) would be to pull off the hose at the manifold, fill the hose with fluid, manually extend the cylinder while the end of the hose is in a container of fluid so it gets sucked up into the cylinder, reconnect the hose to the manifold and compress the cylinder (with the resevoir's cap open), so the excess fluid & air go into the resevoir.

    Anyway- air wasn't my issue. My dumb adjustments were. If things work, don't touch the relief valves!
  5. jmg36344

    jmg36344 Junior Member
    Messages: 5

    Lift cylinder relief valve

    Im having the same issue, how did you go about getting the right tension.
  6. wildbl1500

    wildbl1500 Senior Member
    Messages: 111

    Go to Fisher's website and search the publications for relief valve kit. I didn't replace mine, just used the instructions and setup guide. I would go to the low side of the spec (less turns= more pressure).