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bobcat 743 lost all hyd movement

firedude26 · 2019-06-26 21:03

i was grading driveway and went from reverse to forward and all controls just quit working, no lift or tilt no forward backward, there was a ticking kinda noise , not sure what went wrong or how to test , im thinking the hyd pump took a crap. any help would be great. i just replaced the motor, and there was a small leak coming from the pump, not bad though, and it didnt dump any fluid out when it stopped. thanks

Replies21
  1. #1Ronsii2019-06-26 21:20

    You might have spun the splined shaft from the motor...

  2. #2willie592019-06-26 22:05

    Yep, the 743 had a U joint connection between motor and pumps, that's the first place I'd look

  3. #3Vetech632019-06-27 02:55

    What Willie said ^^^*

  4. #4firedude262019-06-27 20:32

    i just put motor back in it, and the joint seemed fine. i ran it for probly 2 hours or so since. i greased it up and all, whats the easiest way to check that with out pulling radiator out of the way?

  5. #5Vetech632019-06-27 20:46

    It usually strips the splines on either the coupler or the pump shaft. From above it will look normal even if it is stripped internally.

  6. #6Ronsii2019-06-27 20:47

    could be it broke a shaft somewhere.... cause if you lost ALL hydraulics - lift/tilt and machine movment then that would indicate engine power is not getting to the hystat drive

  7. #7firedude262019-06-27 20:56

    i guess we will have to pull motor again, UGH this thing is killing me, let me ask this, the hyd pump is leaking anyway, do u pull that all out from the front? might be easier or make more sense to pull it out and check it all and have pump fixed

  8. #8Ronsii2019-06-27 21:01

    More than likely like Vetech said with the worn splines... happens on lots of different equipment, usually at the pump shaft.

  9. #9willie592019-06-27 21:19

    I have to admit it was like last century when I worked on 743's, and someone can correct me if I'm wrong, but seems I recall one can service that u-joint connection without removing the engine, but I'm not real certain about that.

  10. #10Vetech632019-06-27 21:21

    You have to pull the engine or the pump. The engine removal is quicker and cleaner. You can grease it by performing a 4 ft long arm reach around. LOL

  11. #11firedude262019-06-27 21:23

    i just swapped the 1702 with a 2203 maybe the new power stripped it out, lol i really need to pull the pump and have it rebuilt, anyone in SE MI wannna job???

  12. #12Vetech632019-06-27 21:26

    Those splines wear quickly and most people won’t even notice how bad they are worn unless they have experienced the problem before.

  13. #13Vetech632019-06-27 21:35

    You may want to pull the pump since it is leaking anyway. The good thing is by doing so, you already have it out if you need to replace the driven shaft. You can get to the coupler bolts on the flywheel also. If you pull the engine and find your pump splines bad, then you end up pulling both when it isn’t necessary.

  14. #14firedude262019-06-27 21:43

    i was just reading to where there is a seal behind the spline on the pump, that maybe where my leak is, the forum said you can replace the spline and seal with it in machine??

  15. #15Vetech632019-06-27 21:48

    The seal you can replace as it is an external seal with a snap ring retainer. The female coupler on the flywheel you can change out with either the pump or engine removed. If you need a pump shaft, I always build those vertically on a stand.

  16. #16firedude262019-06-29 11:38

    so since in not able to do the work, would it be easier to pull the pump or motor? i cant find any you tubes on removing the pump

  17. #17Ronsii2019-06-29 11:46

    Pulling the pumps is pretty straight forward, just lift the cab, remove the linkages, undo all hoses/tubes to the pumps and unbolt it.. there are probably a couple little things I forgot it's been 25 years since I pulled one but it's not brain surgery.

  18. #18firedude262019-06-29 13:12

    ok ill ask the guy thats gonna do the work for me what he wants to do, i just had shoilder surgery yesterday so im out if commision for a few months for the heavy stuff

  19. #19firedude262019-07-04 11:31

    OK UPDATE, just pulled motor , the bolt that holds the spline on the Hydro pump backed off and that was it????? i have a new spline, and yoke ordered, there really isnt any wear on either, i have them soaking now in parts cleaner, i cant believe that this happened im happy that it wasnt worse but i am going to change the seal so nom more leaks. the new parts are $450 im noit sure i wanna pay that or just use what i have???? also the dealer said this job would be 20 hours plus parts, i think they are screwing anybody, took motor out in 1 hour flat and that included BS time.

  20. #20Ronsii2019-07-04 12:54

    Glad you found the problem, kinda hard to believe there isn't ANY wear on the splined areas.... but I guess if you didn't run it much after the thing quit it wouldn't wear much... since it don't take that long to remove I would opt for skipping the new parts and then when/if they fail in the future should be an easy fix

  21. #21firedude262019-07-04 13:40

    they spline slipped into the yoke, then the keyway fell out so all it was doing was slipping on the shaft, i think i got real lucky,