Bobcat 741 (same as 743) pintle lever sloppy & weak left side

[pcasey58]

Hi all, I was taking apart the linkages because the sticks were sloppy and left drive function is weak. I've already tried swapping drive motors and there was no change. I noticed with the machine running on the ground the rear pintle lever which controls the left drive was bouncing back and fourth . I am assuming there is a problem with either the high pressure or replenishing valve but not sure which one would cause this condition. This has been giving me problems for a long time and I think I'm getting close to fixing it but dont know what would make the pintle lever bounce like that. I would appreciate any feedback ps the machine was not moving at all while the pintle lever was bouncing. is there a shaft or something that may be worn out?

 

[Adam A]

Try this post. Very informative. http://www.heavyequipmentforums.com/showthread.php?19690-Repairing-creeping-Bobcat

 

[Tazza]

Try this post. Very informative. http://www.heavyequipmentforums.com/showthread.php?19690-Repairing-creeping-Bobcat

A 743 has a different style of centering plate/stoppers than the later models as shown above.
What do you mean that the pintle flops around? Do you mean that there is no resistance when you move the leter back and forth?
It is possible that the issue is internal wear. These pumps aren't that expensive to repair if something is too warn.

 

[pcasey58]

A 743 has a different style of centering plate/stoppers than the later models as shown above.
What do you mean that the pintle flops around? Do you mean that there is no resistance when you move the leter back and forth?
It is possible that the issue is internal wear. These pumps aren't that expensive to repair if something is too warn.

Hi Tazza, Sorry I missed your reply. Ill try to describe it the best I can. With the engine running and both levers in the neutral position, the front lever (right side control) stays straight up and doesnt move. The Rear lever (left side / problem side) moves towards the front of the machine and towards the back of the machine. It seems like the lever moves back and forth with the engine rpms. I will try to take a video and post it. Also I removed the replenishing poppet and relief valve for the left side today and had a stupid question... Is there a cam inside the relief valve or does everything move in one piece? the valve I am talking about is the one below. Is there a cam that moves inside that circle opening or does the whole unit move in and out?

 

[pcasey58]

Hi Tazza, Sorry I missed your reply. Ill try to describe it the best I can. With the engine running and both levers in the neutral position, the front lever (right side control) stays straight up and doesnt move. The Rear lever (left side / problem side) moves towards the front of the machine and towards the back of the machine. It seems like the lever moves back and forth with the engine rpms. I will try to take a video and post it. Also I removed the replenishing poppet and relief valve for the left side today and had a stupid question... Is there a cam inside the relief valve or does everything move in one piece? the valve I am talking about is the one below. Is there a cam that moves inside that circle opening or does the whole unit move in and out?

http://www.loaderpartssource.com/bobcat-parts/bobcat-hydraulic-pumps/hydraulic-drive-pump-relief-valve-to-replace-bobcat-oem-n7926.html this is the valve in question

 

[Tazza]

http://www.loaderpartssource.com/bobcat-parts/bobcat-hydraulic-pumps/hydraulic-drive-pump-relief-valve-to-replace-bobcat-oem-n7926.html this is the valve in question

There is no cam in it, they have a poppet and seat, as the resuure rises, it pushes the poppet up to allow fluid to pass by.
I'm not sure why the lever is moving on it's own, if the centering is not adjusted correctly, the steering lever can rock back and forth, i have had a machine that this happened to. I adjusted the neutral and it was fixed.
With the cab up, you should be able to hold the pintle levers (where the steering sticks attach) and jiggle back and forth and they should not have any play if adjusted correctly. If you push hard enough they will move the spring.