2000 Bobcat 863 bucking/jerking

[thejrancher]

Hi guys, I wanted to give you an update on my problem which I posted previously with this title about a week ago. I got the service manual and first thing I did was take off the top plate with the spring on one end above the pumps to check for wallowing and found the shafts to be tight no problem there. Next I switched drive motors, and lo and behold the problem switched leading me to believe I either need to have the drive motor replaced or rebuilt. Any input on new or rebuilt? I am leaning towards new. I can't thank you guys enough for all your help, I have no experience working on Bobcats before, I have done a lot of auto repair work, rebuilt engines, restored tractors etc. but no Bobcats. This forum gave me a great resource of how to info and I appreciate the support and time you guys give. Thanks,Bill

 

[thetool]

If it is indeed the motor as it sounds like it is, you can't go wrong with the new one, if it's affordable for you.
Your manual will show you how to disassemble and reassemble your motor, how to inspect, etc., but as you are aware parts may be more costly than a new unit.
The only potential problem I see is once your repair is completed, you will have a new or rebuilt, “stronger” motor on one side and this may be apparent.
Also, whenever I R&R'd a motor I always replaced all O-rings-Motor O-ring and plastic shaft seal(blue or white flat ring), and hose fitting bosses. Got a lot of ribbing for this but never had one come back leaking after I repaired it.
Good Luck

 

[thejrancher]

If it is indeed the motor as it sounds like it is, you can't go wrong with the new one, if it's affordable for you.
Your manual will show you how to disassemble and reassemble your motor, how to inspect, etc., but as you are aware parts may be more costly than a new unit.
The only potential problem I see is once your repair is completed, you will have a new or rebuilt, “stronger” motor on one side and this may be apparent.
Also, whenever I R&R'd a motor I always replaced all O-rings-Motor O-ring and plastic shaft seal(blue or white flat ring), and hose fitting bosses. Got a lot of ribbing for this but never had one come back leaking after I repaired it.
Good Luck

Hi guys, I disassembled the drive motor,it all looked good,no pitting,no distorted seals. When I got to taking the pistons and rollers out of the block one of them was hung up, it would only stick out about 1/2" and no more. I finally got it out, the piston wall is scarred pretty good,definitley beyond repair and the ring is broken in pieces embedded in the groove on the piston. The walls of the cylinder are not scarred, a little marked up, look like they could be buffed out with emery cloth or maybe a dremel tool buff head. Anybody have any suggestions on what to buff with. I figure a seal kit and a new piston and ring should make it right. Am I on the right track?

 

[Tazza]

Hi guys, I disassembled the drive motor,it all looked good,no pitting,no distorted seals. When I got to taking the pistons and rollers out of the block one of them was hung up, it would only stick out about 1/2" and no more. I finally got it out, the piston wall is scarred pretty good,definitley beyond repair and the ring is broken in pieces embedded in the groove on the piston. The walls of the cylinder are not scarred, a little marked up, look like they could be buffed out with emery cloth or maybe a dremel tool buff head. Anybody have any suggestions on what to buff with. I figure a seal kit and a new piston and ring should make it right. Am I on the right track?

That sounds like your problem.
I don't know if you can just buy pistons though, i guess you can call around and see what your options are. Even slight scoring will allow oil to by-pass, but if you are willing to take the chance its up to you. If its only for personal use you should be ok. Make sure you check your oil cooler is clear, there must be a reason for it to fail, heat is usually a factor in motor/pump failure.