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boom down slow

John Schroeder · 2022-05-24 11:10

Hi i have a 200lc John Deere Excavator when i activate to boom down function then the boom moves down really slow i checked the high pressure at the pump and it making the full pressure it should , so i checked the pilot pressure that is moving the spool and it has pressure there to so i took out the spool and its moving smooth. Any idea what could be the problem

Replies10
  1. #1uffex2022-05-24 13:10

    Good day John If you raise the undercarriage from the ground is it holding? Kind regards Uffex

  2. #2John Schroeder2022-05-24 17:27

    yes but it's almost impossible to raise the track. but once it's raise it holds it there

  3. #3funwithfuel2022-05-24 18:22

    Do you have line rupture valves on your cylinders? Do all other functions work properly? Bucket, swing and arm? If so, with what you've stated, I'd say something is blocking oil flow from plus side of cylinders to MCV. I would turn the house 90° to the tracks. Get the arm and bucket landed, then lay those cylinders on a block of wood on the tracks. Get the rods out and see if maybe something came off the rod. Nut, fold washer, piece of seal, who knows. It sounds like something is letting oil in and preventing it from escaping.

  4. #4fastline2022-05-24 19:29

    Did you actually check pilot pressure at the spool when operating? What is the pressure at the spool with full boom down stick? Those should have a regeneration circuit for boom down, but once you are pushing down, like lifting the tracks, that is no longer an issue.

  5. #5Dave Neubert2022-05-24 20:14

    try to swap a pilot line from another function and see if the boom works

  6. #6uffex2022-05-25 03:19

    Good day Attached may be helpful. Kind regards Uffex

  7. #7uffex2022-05-25 04:45

    Good day According to my schematic the only component that can prevent boom lower is that of the creep prevention valve, this is released by pilot signal. KInd regards Uffex

  8. #8mg23612022-05-25 05:17

    Sounds like the Boom Reduced Leakage Valve Poppet or it's pilot valve are stuck. Post a picture of the top of your control valve.

  9. #9funwithfuel2022-05-25 06:10

    So, to recap, boom up and all other functions are fine? Only boom down is affected? Pump pressure rises to unload during boom down? You have physically removed and inspected Boom spool and there are no broken springs, no trash in the spool caps?

  10. #10John Schroeder2022-05-25 15:43

    good day thanks for all the Info . I found the problem, the filter that is in the Boom Regenerative Valve was plugged