Bobcat 743 Issues

[dirtbiker245]

This 743 has been sitting around my dads yard for 15 years or so. It has under 500 hours on it.

• About 10 years ago:
  -My Dad was driving it and broke the u-joint between the motor and hydrostatic pump so he had no movement of any kind, just motor running.
  -He took the motor out, changed the joint and put it back together but never finished.
  -all hoses were still disconnected and capped and starter was not put back in as well as random peripheal components.

• About 3 years ago
• I got to it and wanted to get it going. I finished putting it back together.
• -I got it to start and run after having changed all the hoses and changed all oils and filters.
• -It only would go backwards at normal speed and forwards at VERY slow speed.
• -The arms lifted and the bucket tilted both directions no problem.
• -It had lots of shaking and noise that would stop when I would put it in full speed reverse.
• I got frustrated and needed a working skidsteer for a job and bought a 2 year old S205.

• Fast forward to now.
• -I have a ranch property that I'd like to have this at permanently while using the s205 at jobs.
• -Motor started first click, no issues there. lift arms go up and down, bucket tilts.
• -There is still lots of noise and vibration while idling or at any engine speed. The vibration and shaking dissapears when I go full reverse.
• -The issue now though is that it wont go forward or reverse at all.

I checked the linkage, and while it may not be "perfect" it should be at least giving me some sort of movement.
I checked the fluid levels and they all seem "correct" or close to me. Im thinking maybe I have air in the hydrostatic system?
Any other advice? Ideas? Ive been looking at the manual and the troubleshooting guides but am lost at this point.

-Riley

 

[OldMachinist]

It may have damaged the input shaft and bearing on the pump when the u-joint broke.

 

[dirtbiker245]

It may have damaged the input shaft and bearing on the pump when the u-joint broke.

Though that would make sense, the lift and tilt functions work normally.

I have been attempting to change the port block bronze filter.... I think I broke something trying to get it out. how are you supposed to take it out. I see the filter in there, the bronze with a threaded end. I assumed I put a nut on the threads and grab it with vise grips and pull... so now the threaded part broke off, and the filters still stuck in the port block... never a dull moment.
Ideas? Suggestions?

 

[brdgbldr]

Though that would make sense, the lift and tilt functions work normally.

I have been attempting to change the port block bronze filter.... I think I broke something trying to get it out. how are you supposed to take it out. I see the filter in there, the bronze with a threaded end. I assumed I put a nut on the threads and grab it with vise grips and pull... so now the threaded part broke off, and the filters still stuck in the port block... never a dull moment.
Ideas? Suggestions?

I'm only taking a guess...(All of you experts don't laugh, it happens) Are you sure that the drive motor lines are hooked up correctly?

 

[[email protected]]

I'm only taking a guess...(All of you experts don't laugh, it happens) Are you sure that the drive motor lines are hooked up correctly?

make sure you dont have the aux hydraulics engaged with nothing hooked up to it, makes the hydraulics act screwy.

 

[dirtbiker245]

I'm only taking a guess...(All of you experts don't laugh, it happens) Are you sure that the drive motor lines are hooked up correctly?

I have the port block off right now and am changing the bronze filter and cleaning out the block completely.
I will verify all lines when I re-assemble, however I did check through them and they all appeared correct.

 

[Tazza]

I have the port block off right now and am changing the bronze filter and cleaning out the block completely.
I will verify all lines when I re-assemble, however I did check through them and they all appeared correct.

If the shaft isn't bent, ensure the u-joints are free to move. I had one that shook a lot because the u-joint bound up a little when i installed it. Pulled it out and machined a bolt down, vibration was gone.
The lift and tilt run off the pump at the front of the drive pump. Not the same pump that drives teh wheels.

 

[7LBSSMALLIE]

If the shaft isn't bent, ensure the u-joints are free to move. I had one that shook a lot because the u-joint bound up a little when i installed it. Pulled it out and machined a bolt down, vibration was gone.
The lift and tilt run off the pump at the front of the drive pump. Not the same pump that drives teh wheels.

743 shakin and vibration;;; was a pump alingment done.(this would not account for fwd rev thing . EVERY TIME 743 ENG PULLED PUMP ALINGMENT NEEDS DONE> I GOT A FANCY GO OR NO GO JIG. it mounts in eng mount holes basic piece o pipe that slips over shaft easy when alingened. you can do this without it looking for x and y axis but keep in mind level factor as well stat is shimable up down left and right as well as level.(to eng ) the rear back plate that eng sits on likes to get bent check it. also flywheel fins broken throwing weight off or bolt interference. also keep in mind the stat input shaft coulper is a taper if that 3/8 BOLT OVER TIGHTENED.(been there done it) male coupler splits and widendens . not allowing full fit to u joint(bunching it up) impacts make life easy but they can hurt you too, didnt mean to ramble just a few thoughts for a kindered spirit. (buy the way i would love to know if i was right)