Heavy Equipment Forums Heavy Equipment Community

Boom stops when dipper or bucket used

Bruce George ยท 2013-07-24 15:50

I have an '85 JCB 1400B. When raising boom and pulling dipper too hard simultaneously ,the boom stops rising till I reduce demand on dipper. Same thing if I open or close bucket while raising boom. Could this be some type of priority valve malfunction or dirty hydraulic filters ? Any suggestions appreciated.

Replies9
  1. #1mikebramel2013-07-24 21:57

    Sounds normal for a open center single pump machine

  2. #2jughead2013-07-25 06:19

    my ford 655 does the same thing and i dont like it

  3. #3robin yates uk2013-07-25 06:25

    ,,,,,,,,,,,what engine speed are you using when digging ?

  4. #4Bruce George2013-07-26 08:51

    All rpm ranges. But I'm going to change the filters and see how it goes

  5. #5Tony H2013-08-02 15:19

    How did you make out? I was wondering if the Fluid Flow was choked out by a dirty filter

  6. #6mikebramel2013-08-02 17:25

    If the filter was plugged the bypass valve would open. If the bypass valve failed the filter sheet metal or filtering element would blow

  7. #7stumpjumper832013-08-02 17:32

    Again sounds normal... either get used to it our dig out the franklins for a newer machine with more pumps. Some of the new bobcat mini excavator are that way as well just so you know, and yes, your right it is annoying.

  8. #8Bruce George2013-08-04 13:23

    Thanks for the reply. I can still use the machine fine. Sounds like that's normal

  9. #9Bruce George2013-08-04 13:26

    I've been too busy to try it yet. Always something else side tracks me.