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bobcat 743 lost all hyd movement

firedude26

Active Member
Joined
Dec 22, 2010
Messages
35
Location
se mich
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
 

willie59

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Dec 21, 2008
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Knoxville TN
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Service Manager
Yep, the 743 had a U joint connection between motor and pumps, that's the first place I'd look
 

firedude26

Active Member
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Dec 22, 2010
Messages
35
Location
se mich
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?
 

Vetech63

Senior Member
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Aug 10, 2016
Messages
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Location
Oklahoma
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.
 

Ronsii

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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
 

firedude26

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Dec 22, 2010
Messages
35
Location
se mich
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
 

Ronsii

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

willie59

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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.
 

firedude26

Active Member
Joined
Dec 22, 2010
Messages
35
Location
se mich
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???
 

Vetech63

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

Vetech63

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Aug 10, 2016
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Oklahoma
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.
 

firedude26

Active Member
Joined
Dec 22, 2010
Messages
35
Location
se mich
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.
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??
 

Vetech63

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Aug 10, 2016
Messages
6,362
Location
Oklahoma
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.
 

firedude26

Active Member
Joined
Dec 22, 2010
Messages
35
Location
se mich
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
 

Ronsii

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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.
 

firedude26

Active Member
Joined
Dec 22, 2010
Messages
35
Location
se mich
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
 

firedude26

Active Member
Joined
Dec 22, 2010
Messages
35
Location
se mich
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.
 
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