bobcat 853 Hydro pump locked up..

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slik rik

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Joined
May 17, 2011
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40
So working my always trusty 853 around the site, spreading dirt piles. Overloaded it and stalled her out, started back up but with a slight squeal on the belt, happened again a while later, same thing slight squeal. Happened a third time, wouldnt start, it started to turn over, louder belt squeal, and stop.

So at this point I try a couple times and give up, check fluids, fine, take belt cover off and check belt tension, seems fine, end up removing tensioner and belt, motor starts fine , as usual. Cant move the pump pulley by hand, hmm.....I also worked the hydro controls to relieve pressure.

Now a few questions:

Should I be able to move the hydro pulley by hand, no wrench yet, may cut hole in side for access to nut?

Would there be a relief valve sticking that would cause the hydro pump to lock up?

Any Ideas from anybody would be appreciated.

My next order of things is to release the lines from the pump and see if I can spin it, thats all I can think of.
 
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slik rik

Active member
Joined
May 17, 2011
Messages
40
Well next day and I found a repair manual for the bobcat hydro pump, from bobcat. So its a sundstrand pump not sure the series or model but will get there. So plan of attack is this: Check to see if I can rotate pump by hand, if not Im gonna drill a hole saw through side of bobcat to access the pump oulley, like 2" diam, I'm hoping that a releif valve got stuck and jammed the pump up. Maybe had some leakdown overnight. If it doesnt move than I will go about releasing the hoses off the pump, and possibly pull the charge pump off. then see if it moves.

The machine showed no issues before yesterday, plenty of power hydro pushing hard, just an all of a sudden stop.

Will update later.
 
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slik rik

Active member
Joined
May 17, 2011
Messages
40
bobcat hydro manual.png
 
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