644 lbh backhoe bucket won't curl under pressure
Page 1 of 2 12 LastLast
Results 1 to 10 of 20
  1. #1
    Super Mod Harry's Avatar
    Join Date
    Mar 2015
    Location
    Lockport NY
    Posts
    1,799
    Thanks
    3,073
    Thanked 1,454 Times in 705 Posts

    644 lbh backhoe bucket won't curl under pressure

    I completed my trenching bucket and went to use it today. I trenched about ten feet then the curl wouldn't work under pressure. I also noticed the crowd wouldn't work under pressure either. When no pressure out of the trench they worked fine. Do you think it's in the cylinders leaking by internally or the control valve?

    Keep the Peace
    Harry

  2. Remove Advertisements
    CaseColtIngersoll.com
    Advertisements
     

  3. #2
    Member Timj's Avatar
    Join Date
    Dec 2019
    Location
    Wild Rose, WI
    Posts
    97
    Thanks
    0
    Thanked 44 Times in 29 Posts
    Hi Harry, with more than one cylinder not working under pressure, I would be thinking control valve, maybe relief valve. Does it have power under pressure on the other cylinders?

  4. #3
    Super Mod Harry's Avatar
    Join Date
    Mar 2015
    Location
    Lockport NY
    Posts
    1,799
    Thanks
    3,073
    Thanked 1,454 Times in 705 Posts
    Yes Tim the boom, down riggers and the left and right swing appear to work fine. It started to rain so I stopped the trenching for today. I'll try it again soon and give an update. I know there is enough oil in the tank and it only was under stress that it seemed to stall. No noise it just stopped curling.

    Keep the Peace
    Harry

  5. The Following User Says Thank You to Harry For This Useful Post:

    gator_rider2 (08-16-2020)

  6. Remove Advertisements
    CaseColtIngersoll.com
    Advertisements
     

  7. #4
    Senior Member sdunt's Avatar
    Join Date
    Apr 2017
    Location
    Central Illinois - Bloomington
    Posts
    1,595
    Thanks
    103
    Thanked 1,122 Times in 592 Posts
    In my mind attempting to diagnose this, what is common to those 2 cylinders? If the rest of the tractor and hoe works and has power, it would be really odd for the seals in two cylinder to fail at the same time.

    any commonality in the control valves for those cylinders? Its very likely you're going to need a pressure gauge to diagnose if this is the cylinders or something else. Something along the lines of this: https://www.amazon.com/Measureman-Hy...s%2C226&sr=8-4

  8. The Following 2 Users Say Thank You to sdunt For This Useful Post:

    gator_rider2 (08-16-2020),Harry (08-17-2020)

  9. #5
    Tractor Whisper gator_rider2's Avatar
    Join Date
    Jan 2011
    Location
    Glennville, Georgia
    Posts
    3,703
    Thanks
    1,115
    Thanked 1,313 Times in 832 Posts
    https://manuals.casecoltingersoll.co...%209-50741.pdf

    Go to page 14 this loader valve there 3 caps from right to left close to spool third single cap to left one has broke spring are stuck open relief. its spring item 18 it maybe trash holding relief open you find trouble there. on bottom valve has same.

  10. The Following 3 Users Say Thank You to gator_rider2 For This Useful Post:

    74_case_onan (08-17-2020),dave1mn2 (08-17-2020),Harry (08-17-2020)

  11. #6
    Super Mod Harry's Avatar
    Join Date
    Mar 2015
    Location
    Lockport NY
    Posts
    1,799
    Thanks
    3,073
    Thanked 1,454 Times in 705 Posts
    I finished up the trenching the other day and the curl worked fine. I'm not sure why it stopped the first time I used it. Thanks for everyone who replied to my dilemma.

    Keep the Peace
    Harry

  12. The Following User Says Thank You to Harry For This Useful Post:

    gator_rider2 (08-25-2020)

  13. #7
    Senior Member
    Join Date
    Oct 2017
    Location
    Fond du Lac , Wisconsin
    Posts
    231
    Thanks
    21
    Thanked 153 Times in 93 Posts
    Like Gator said, it may have been something stuck in relief valve holding it open and it "flushed" itself clear.

  14. The Following 2 Users Say Thank You to Garyc For This Useful Post:

    gator_rider2 (08-25-2020),Harry (08-26-2020)

  15. #8
    Super Mod Harry's Avatar
    Join Date
    Mar 2015
    Location
    Lockport NY
    Posts
    1,799
    Thanks
    3,073
    Thanked 1,454 Times in 705 Posts
    I tried the backhoe again last week and it wouldn't curl, so i decided last weekend to check the relief valves on the backhoe. I did find a little spouge in the one valve and some sediment in the bottom of the valves, no broken springs. I tried the backhoe out this morning and it worked like a champ, no hesitation or stopping. The dipper also seemed to work great.

    I'm digging some dirt in my backyard, using it to fill in low spots and then plant some grass for a fall planting. It's creating a low spot in the back which will fill in with water from the winter thaw. I'll post some pics the next time I'm using the backhoe.

    A big thank you to Gator for giving me the manual link and the suggestion how to fix my situation.

    Keep the Peace
    Harry

  16. The Following User Says Thank You to Harry For This Useful Post:

    CobyDog$10 (09-17-2020)

  17. #9
    Super Mod Harry's Avatar
    Join Date
    Mar 2015
    Location
    Lockport NY
    Posts
    1,799
    Thanks
    3,073
    Thanked 1,454 Times in 705 Posts
    Yesterday I was using the backhoe to move some dirt and the bucket suddenly wouldn't dump. All other functions for the backhoe appeared to work fine. When activating the dump lever the bucket starts to move but it appears to be struggling to the point that the engine will stall out. I removed the relief valve again and checked for a broken spring or dirt and found nothing. It seems like there is a restriction in the hydraulic hose so the oil won't flow to retract the cylinder ram. Any suggestions out there? Maybe it's time for a cylinder rebuild!

    Keep the Peace
    Harry

  18. #10
    Senior Member
    Join Date
    Feb 2014
    Location
    Ayr, Ontario
    Posts
    420
    Thanks
    569
    Thanked 602 Times in 212 Posts
    Harry, my guess is that hose interior failure is letting debris plug return ports. I would probably remove the return line at or near the valve and watch for flow. It should be and indicator of plugging at the valve or of a cylinder rod failure.

    I spent 4 days tuning a system last week. It had 15 years of no maintenance, no filter or oil changes. Even in a closed system it was incredible how much rubber was packed in the filter and cylinder ends. System would run about 2 hours before stalling due to temperature rise, oil breakdown, and filter plugging.

    Your issues are an encouragement for me to do a complete and thorough rebuild on my 646B hydraulics before painting.

    Eugene

  19. The Following 2 Users Say Thank You to Eugene Slagell For This Useful Post:

    dave1mn2 (09-19-2020),Harry (09-19-2020)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •