Heavy Equipment Forums Heavy Equipment Community

KOBELCO SK 210 -6E

pasinead1991 · 2023-02-01 11:07

Hi everyone I have a problem with a kobelco sk210-6 when arm is all the way out it falls back in but only if all the way out otherwise function is normal

Replies8
  1. #1Kobelco ireland2023-02-01 13:46

    How fast does it fall. Does it fall to horizontal position. Does it have a hose burst valve on the cylinder

  2. #2uffex2023-02-02 04:32

    Good day The post sounds as if the spool or valve is sticking open. Kind regards Uffex

  3. #3pasinead19912023-02-03 04:27

    No hoses burst and no valves on cylinder it has some sort of a way to stop oil flow before the cylinder rod comes to a stop I believe it’s a valve on the valve chest that dose this would anyone have a detailed break down of the valve chest/body. The arm works fine until you reach the end of its stroke rod completely in then it falls to a horizontal position until you put pressure on the cylinder rod out then it’s operation is normal again it only happens when rod is all the way in if I stop just before the rod is completely in it will not fall in the arm will stay there all day long

  4. #4Kobelco ireland2023-02-03 04:30

    First thing I would try is swapping the arm in and arm out port relief valves and see if that makes any difference.

  5. #5uffex2023-02-03 07:29

    Good day From your latest post I have the impression that you are low on flow to the arm cylinder, do you have full engine revolutions. If you have a hydraulic schematic for your machine, that would help to pinpoint the cause. I believe that Kobelco rely on the main spool to control arm speed-flow both for feed and return, it could be that a second pump is not activating to help with arm in cylinder out. Measuring the speed of the arm can be very helpful. Kind regards Uffex

  6. #6uffex2023-02-03 07:35

    Good day You may find the attached useful to trouble shoot. One other thought if your machine has a pattern change valve, be sure it is fully selected. Kind regards Uffex

  7. #7pasinead19912023-02-03 11:34

    Thank you for the download very helpful I will check over the weekend and will let you know what I found.

  8. #8Kyle Helmke2023-03-01 04:10

    The cylinder rod is stopped internally by what's called a cushion. It slows down the amount of oil able to escape the cylinder. It sounds like you have internal damage to the cylinder allowing oil to bypass the piston at the end of the barrel.