Bobcat 751 jerky right/left steering

[asforme]

I have a Bobcat 751. I purchased it in 2005 and am the second owner. I have only done filter, oil and grease maintenance on it. Since the day I bought it, it has always had VERY sensitive right/left steering. Bucket tilt/raise is OK and forward/backwards is OK. At low-speed it turns nicely, no jerking just smooth operation, however when you speed it up the right/left steering is so sensitive that there is an initial jerk then typical turning. The jerking happens in both directions. Say I need to turn right, it will jerk then I need to reverse control and it will jerk the other way. Sometimes I need to let go of the controls to get control. If I used the 751 for business, it would have been fixed long ago, however low-speed operation is fine for work on my farm. I have the original maintenance and parts manuals. Any help would be appreciated.

 

[bobbie-g]

I have a 751 (at my son's house now). The steering on it has always seemed a bit more touchy than other mechanical joystick machines. Having said that, it sounds like yours is a bit worse than it should be. Have you popped up the cage and looked at the linkages? Can't remember about that machine, but my current machines (763, 863) have rubber linkage connections which can wear out or degrade. Also, have you looked at the rear portion of the linkage where the horizontal linear motion is converted to rotary motion? The hydraulic control valves are inside the large pump assembly, just about under the back edge of the seat with the cage down. Those control valves are actuated by two vertical shafts, one for either side. Each shaft is rotated (to produce the forward/rearward tire rotation) by an aluminum bell crank. There is a clamp holding the aluminum bell crank to the vertical shaft. Often, these clamp bolts work loose so the shaft motion gets sloppy or erratic. (If the aluminum bell cranks won't tighten up via the bolt, you might try making a couple of shims out an aluminum coke can to slip in there to take up some of the wear slop). I think on the 751 those bolts are accessible easily. Not so on the 863. So those are a couple of things to check, engine off, cage up. Just wiggle the joysticks slightly to see if you can produce a nice, smooth rotation of the vertical shafts. Holler if you can't figure out how all that stuff works together. I suspect that design was worthy of a graduate thesis project. But it works well when adjusted correctly. Bobcat used that design for many years. ---Bobbie-G