Bobcat 753 drive is jerking

[poepjin]

I recently purchased an older 753 serial# 508615824 The engine has only 1080h on it, but the machine was sitting for quiet a while. So I serviced everything, replaced hoses, the whole tlc. After all I tested the machine and it worked great, had to adjust the neutral a little and everything was fine.
Then on one of the drive motors oil started to leak; I found on one of the hoses the o-ring went bad. So I replaced it and the leak stopped. But now that motor is jerking in forward; I have to push the steering lever hard forward and back to get the motor going and then it feels like it slows down again, but it's only in forward a problem, reverse seems to work ok. I was thinking if there is air in the system that needs to be bleeded? But I couldn't find any info for something like that, so that's probably not the problem.
What could it be then, I only changed the o-ring and before it was working fine?
Thanks for any advice.
pj

 

[poepjin]

By now I can answer this myself: Took out the motor and found pieces of the old o-ring were stuck in the directional check valve/relief. To make sure I opened up the whole thing and also saw that parts of the interior seals were totally deteriorated; they literally dissolved. So I ordered a new seal kit and got new o-rings; waiting for it to arrive and slam it back together, and call me an experience richer.
Thanks.
pj

 

[crashz]

Good info Poepjin! I would have been hoping it was an adjustment on the lever arms, never got brave enough to get into the gearcase or drive motors myself!

 

[poepjin]

Good info Poepjin! I would have been hoping it was an adjustment on the lever arms, never got brave enough to get into the gearcase or drive motors myself!

Well, I was reluctant, but now after opening it up I can say it is much more simple than other hydraulic components I have been working at. It's just important to assemble it correctly back together.
pj

 

[Bingo9991]

How hard was the repair? Never been under a bobcat really but I'm quite good at putting stuff back the way I found it, my grandpa has an older bobcat that has the same problem (machine has never been taken care of, probably still on the original oil lol)

 

[airbiscuit]

How hard was the repair?...

I am also interested in the difficulty factor. I had a Bobcat 642 for a while, and I had a lot of fun with it, but you had to be a contortionist to work on it. The access ports are jussssst barely big enough to turn a wrench, and a lot of what I had to do seemed to be at extreme arms length. I commend you for diving in.