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  1. #1
    Elite Member Richard's Avatar
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    Knoxville, TN
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    Fullsized JCB Loader/Backhoe

    Default Valve rebuild for Industrial backhoe

    Ok... dumb question probably....

    I sprung a leak on one of the supply side hoses to my backhoe control valve. Machine is off, nothing happens, machine is ON, I got a steady though currently small, stream of fluid blowing out of this hose.

    My bucket will droop and the boom will drift to one side, so I am going to use this crawling under to fix my hose, as an opportunity to take the valve assembly off and rebuild it.

    The dealer says the "typical" rebuild is only "O" rings. My luck usually doesnt' run that way, but fingers are crossed.

    Anyone have an interest in my taking pics of the process and posting them here?

    (know upfront, the basic parts ordered yesterday, take week to get in, week to do perhaps, then couple days to get film back)

    So we're not talking stories by this weekend.

    I'm sure it'll be a VERY messy job, so I figured I'd not venture under there with camera unless someone wants to see what's happening. (going under to only REMOVE valve block...I'll rebuild it off machine).

    ??


  2. #2
    Super Member RobS's Avatar
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    SW Michigan
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    John Deere 790

    Default Re: Valve rebuild for Industrial backhoe

    Of course we want to see pictures of that Richard [img]/forums/images/graemlins/grin.gif[/img] Also though, what lead you to the conclusion that it needed a rebuild?

    [img]/forums/images/graemlins/smile.gif[/img]

  3. #3
    Elite Member Cliff_Johns's Avatar
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    Northern Illinois
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    JD 4110

    Default Re: Valve rebuild for Industrial backhoe

    Absolutely post pictures if you can. Photo essays are always useful even if that's not the specific job the reader needs to do, and a real boon to anyone in the future who has to do a similar thing.

    Cliff

  4. #4
    Elite Member Richard's Avatar
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    Fullsized JCB Loader/Backhoe

    Default Re: Valve rebuild for Industrial backhoe

    Ok.. I'll plan on taking pics... what drove this? first off, machine is circa 1987 and "probably" has original stuff in it.... more to the point though, I HAVE repacked the bucket cylinder and it will droop/drift visibly from the up position...leaving ONLY the valve block as culprit.

    Secondly, the boom will drift to the right side "passenger side" when going straight down a hill OR going sideways on hill with right side to downhill side. It will NEVER drift to the 'drivers' side. Now, the dealer DID suggest I try test a/b to verify, but the bucket alone needs it, so if I'm gonna fix that, I'd just as well figure to do it all [img]/forums/images/graemlins/grin.gif[/img]

    That all said, the primary reason I'm going under there is to replace the large supply hose (or return??) that popped a pinhole in it. I took that hose off tonight & will replace it tomorrow.

    The rebuild kit, which consists primarily of washers/seals is costing me $100. This presumes all springs, valves, extenders or any other various parts are ok...if not, I'll replace them too. I figure for $100 & my time?? it will be an interesting endeavour as long as I dont need any special tools.

    [img]/forums/images/graemlins/cool.gif[/img]

  5. #5
    Veteran Member
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    Oklahoma City
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    Deere 855 (24hp/19@PTO)

    Default Re: Valve rebuild for Industrial backhoe

    <font color="blue"> I HAVE repacked the bucket cylinder and it will droop/drift visibly from the up position...leaving ONLY the valve block as culprit. </font>

    Hi Richard,
    I know very little about this, but I think all yellow tractors have cylinder check valves, which prevent drift down. I always assumed the check valves would be part of the control valve block assembly. Recently, I was surprised to find out that often the check valve is built into the cylinder itself. It's a safety feature, so that if a hydraulic line blows, the loader or backhoe won't come crashing to the ground, but should stay frozen in the position it was in when the line blew. If the check valve was part of the valve block, it wouldn't prevent a crash.

    At least, that is the way I understand it. If your bucket is drifting, then a cylinder rebuild or valve block work may not be what you need. It could be the check valve that needs attention and that might be located somewhere other than the valve block.

    OkieG

  6. #6
    Elite Member Richard's Avatar
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    Fullsized JCB Loader/Backhoe

    Default Re: Valve rebuild for Industrial backhoe

    Interesting point about the checkvalves...I'll need to ask the dealer. That said, with the ideas you presented, my gut says I dont have ANY checkvalves [img]/forums/images/graemlins/blush.gif[/img]

    I dont know that... only base that on what you said &amp; what's happened in past... for example: Once was clearing up a slash pile area, going backwards, kicked up a log (spear) it rammed into my valve block (this same one) severed a hose and my backhoe just went WHUMP and fell to the ground. I was very confused as to why it did it (presumed I'd hit something SOMEHOW) I reached back to pull lever to raise boom and an AMAZING display of high volume, high pressure hydraulic fluid absolutely SHOT out the backside of machine where the hose use to be. I turned it off &amp; found said damage.

    Another time, same experience essentially, I was pushing some dirt away &amp; my crowd cylinder died as a hose burst there too.

    Upshot, my gut tells me I have NO checkvalves, or if I DO, they've checked out already!!

    [img]/forums/images/graemlins/grin.gif[/img]

  7. #7
    Gold Member
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    Default Re: Valve rebuild for Industrial backhoe

    most of the machines i've seen do not come with checkvalve, and have to be retro fitted, if the machine is going to be used for lifting, or hoisting on a job site.

    what breed/model machine do you have?

  8. #8
    Elite Member Richard's Avatar
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    Fullsized JCB Loader/Backhoe

    Default Re: Valve rebuild for Industrial backhoe

    JCB 1550-B (Digs 2 foot bottom at 15 1/2 feet as I understand it)

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