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Lull 644d-34

Discussion in 'Forklifts/Telehandlers' started by Sambusack234, Dec 26, 2021.

  1. Sambusack234

    Sambusack234 New Member

    Joined:
    Jul 12, 2020
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    Location:
    Ocean townshipn
    Please help!, I recently purchased a lull 644d-34 and the automatic fork leveling does not work at all, I wanted to know if you know what this might be, some possible fixes thank you in advance
     
  2. icestationzebra

    icestationzebra Senior Member

    Joined:
    Jun 21, 2009
    Messages:
    354
    Location:
    WI
    I don't have the schematic for the 644D but I looked at one for the C-series which I'm assuming are the the same in this regard. The slave cylinders are simply tee'd into the line for the carriage tilt cylinder. Assuming you can still make the forks go up/down with the joystick then the slave cylinders have either been disconnected or the piston seals are blown out. ISZ
     

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    Delmer likes this.
  3. tractormech

    tractormech Senior Member

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    Will the forks operate normally with the joystick? If so I agree with ISZ. I'd repack the slave cylinders. It sounds like the piston packing may be blown. BUT- before you start tearing cylinders apart check the hoses on the slave cylinders. Make sure someone hasn't crossed the lines. The bottom ports should be hooked to the same line as should the tops. If they got crossed you won't have any self leveling. I've got that hat. Good luck.
     
    Tenwheeler likes this.
  4. icestationzebra

    icestationzebra Senior Member

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    Good point on crossing the hoses - didn't think of that. They could have also hooked the slave cylinder rod ports to the carriage base port and vise versa - but in this case the carriage would tilt back when hoisting. ISZ
     
    Tenwheeler likes this.
  5. tractormech

    tractormech Senior Member

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    It would do that. I ran into the crossed line situation on a 644B-37. The slave cylinders were hooked up with the base of one going to the rod of the other one. Self level was rendered inoperable.
     
  6. Tenwheeler

    Tenwheeler Senior Member

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    Dec 15, 2016
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    Location:
    Georgia
    I do not remember what came after the 644 on the last one I worked on. However a service manual was on line for free.
     
  7. bindian

    bindian Well-Known Member

    Joined:
    Aug 31, 2009
    Messages:
    216
    Occupation:
    Aircraft Mechanic
    Location:
    Willis, Texas
    My 644d-34 fork leveling went intermittant, then went out right after getting my boom hoses replaced. Are the slave cylinders the two cylinders above and behind the boom cylinder?
    My Lull has been in the shop for 6 months and they can't figure it out. I may be bringing it home next week, as I think they are fixin to wash they hands of it. Back when I took it to them, I didn't have time to tinker with it. Now I do have time.
    hugs, Brandi
     
  8. tractormech

    tractormech Senior Member

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    Location:
    florida
    Those are the slave cylinders. If the packings are blown inside you won't have automatic fork leveling. Double check your plumbing on the boom hoses. But intermittent operation and then failure sounds like cylinder packings.
     
  9. bindian

    bindian Well-Known Member

    Joined:
    Aug 31, 2009
    Messages:
    216
    Occupation:
    Aircraft Mechanic
    Location:
    Willis, Texas
    Thanks. I got the hydraulic diagram and that sure looks like an simple circuit. Hope to have it home next week, then will pull those cylinders and get them tested. Thanks again!
    hugs, Brandi