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  1. #1
    New Member
    Join Date
    Nov 2004
    Posts
    23

    Default 790 Hydraulic Problem

    I have a JD 790 with 419 loader. Ever since the tractor was new, the loader (both lift and curl) has leaked down at what I call an unacceptable rate. The more weight that is in the bucket (it leaks down empty too), the faster the leak down. With a loaded bucket, you can physically watch it go down. Even with an empty bucket, it goes down several inches every 10 minutes. I have had it to the dealer three times for this issue. They have been great working with me, but the issue is not corrected and neither they nor me know what else to do. They have replaced all of the cylinders as well as the SCV valve. What could be causing this? What is my recourse? Is there something that could be added (perhaps a check valve) to prevent the leak down? This is an annoying problem as well as potentially dangerous. My own thoughts are that the SCV valve is produced with sloppy tolerances, but that is only a guess. I'm not very well-versed on hydraulics, so I'm seeking input from you gearheads out there that know JDs well. This problem occurs both when the tractor is running and when it is shut off.

    Any help would be greatly appreciated.

    Thanks.

  2. #2

    Join Date
    Jul 2004
    Posts
    273
    Location
    Texas
    Tractor
    JD 4720 2004 / MF230

    Default Re: 790 Hydraulic Problem

    Link

    Here is a thread about this from before, I think it is the one with the factory acceptable rates info.
    May not be for your specific tractor but should be informative [img]/forums/images/graemlins/smile.gif[/img]

    MikePA: Cleaned up long URL. Please review how your message looks before posting it. It's simple not to do this. Just insert a descriptive word or two between the {url=http://whatever}<font color="red">Enter words here</font>{/url} instead of the entire long URL. Replace parentheses with brackets.

  3. #3
    New Member
    Join Date
    Nov 2004
    Posts
    23

    Default Re: 790 Hydraulic Problem

    Thanks for the link, however that chart does not reference the 419 loader. This must be a JD-wide problem if they went to the trouble of posting it on their web site. What I would like to know is does anyone with a 790/419 loader combo have this issue? If so, have you addressed it with your dealer. Is there a check valve somewhere in the system? If not, can one be added somewhere?

    Thanks

  4. #4

    Join Date
    Dec 2004
    Posts
    275
    Location
    Newberg, Oregon, USA
    Tractor
    JD 790

    Default Re: 790 Hydraulic Problem

    For what it is worth. I just got a used 790 with 1319 hours on it, and a new 419 FEL, and I haven't had a full capacity load in the bucket yet, but it has not leaked to any noticable degree at all yet.

    Just out of curiosity, I wll do an experiment with a good load in it (maybe full of water at full tilt up), with the bucket at say 48" and leave it for awhile to see what it does. (yes with appropriate precautions against someone getting hurt by it)

  5. #5
    New Member
    Join Date
    Nov 2004
    Posts
    23

    Default Re: 790 Hydraulic Problem

    I would really appreciate it if you would do that experiment. I expect a certain amount of leakage, but what mine has it what I would consider excessive. Maybe if your test shows that yours doesn't leak down (at least very fast), then I have a little bit of ammo to take back to the dealer. They have been great in working on it, but they still haven't located the problem. At this point I'm thinking of asking for a complete new loader or tractor since this has been an ongoing issue since day one. If it will hold a bucket full of water off the ground six inches for an hour, I would consider that a great success. Mine would hold it that high for about two minutes. Thanks for your time!

  6. #6

    Default Re: 790 Hydraulic Problem

    My 790 w/ 419 loader seems to hold on the lift ...but it does leak down on the curl some ... it's slow about 1" per hour or so ... I'm sure that the lift leak too but it's not as fast ....it will keep the bucket up all night but if it's not curl all the way up it will dump the load over night ...

  7. #7
    New Member
    Join Date
    Nov 2004
    Posts
    23

    Default Re: 790 Hydraulic Problem

    It sounds like yours definitely does better than mine....let me know how the test turns out...

  8. #8
    New Member
    Join Date
    Jan 2004
    Posts
    19
    Location
    Missouri
    Tractor
    John Deere 790

    Default Re: 790 Hydraulic Problem

    Mine also leaks down, although apparently not as fast as yours. When I'm bush hogging with the loader on, I have to recurl the bucket every 10 minutes or so as it starts uncurling. The arms also drop but not very fast.

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