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790E erratic valve

logsrus ยท 2016-04-03 22:37

I have a 790E that the bucket function works slow sometimes. If you put a load on it with the stick it will then only move very slowly. If you wiggle the control back and forth rapidly it will then start to work properly. I don't think it is a sticking spool. Does anyone have any experience with these machines. My suspect is that it may be a compensator valve sticking or a shuttle valve sticking. Has anyone had any experience with this problem........................................................................................

Replies5
  1. #1rkellah2018-11-01 12:01

    I have the same problem on my 790ELC. Did you ever figure out what was causing this?

  2. #2rkellah2018-11-01 12:02

    Also, do you have a TM1506 test manual by chance?

  3. #3carogator2018-11-01 20:27

    Also found this on e-bay:John Deere 790E-LC Excavator Operation & Test Shop Service Repair Manual TM1506

  4. #4uffex2018-11-03 05:19

    Good day Im not sure that your valve spring assembly looks as the illustrated but had a similar experience which proved to be the spring guide. Kind regards Uffex

  5. #5mg23612018-11-03 06:05

    All the other functions work ok? I would get a pressure gauge and tee into the pilot caps on the bucket spool to make sure you are getting pilot pressure (370 psi minimum) to the cap all the time to eliminate that first.