Harry in Ky
Veteran Member
The tractor in question is branded as a Bobcat CT445 but it's still Kioti. Posting this here because I'm thinking the Kioti name may have more "eyes" on it.
It's a DK45 HSE tractor as far as I can see. The problem is this. The hydrostat decided one day to stick in the forward direction. The story as told to me, the tractor was running along as usual with no noticeable problems. Driver stops to open a gate, gets back on and can't get the range shifter to go into gear. Gears are grinding and it just won't shift. Also of note is the reverse pedal has no travel. It's pretty much solid in the neutral position.
A quick look at the external pedal links and pivots shows nothing unusual. After removing a few of the points and joints it turns out the pedals are both operating as the should, the problem is the control shaft going into the hydrostat will not move in the direction of reverse travel. Now what? I tried turning that shaft with a large Crescent wrench and decided that any more force in that direction was probably going to break something.
Searching for information on this tractor and it's transmission I find it's designed with a servo piston operated swash plate. I'm not sure how common that concept is, but my limited hydrostat experience has all been with strictly mechanical operation. I concluded that anything related to this piston mechanism is only accessed from the inside, so any work done on it means the unit come out of the tractor. I finally got the tractor in three pieces on Friday and got the unit out on the floor. Removed the two covers and exposed the piston, which was indeed stuck in the forward position. I now have the unit in another location where I have a reasonable shot at keeping everything clean while it's apart.
I did that today, and expected to find something broken, twisted, jammed, etc in either the piston/bore, or the swash plate mechanism on the inside. Following the procedure I got the pump rotating group out exposing the swash plate and found no problems at that point. Removing the plate requires the piston to be in the neutral position, so at that point I decided to give the piston a little "tap" in that direction, and it moved. Now with the swash plate out everything behind it looks normal, and the piton will go full travel in both directions with just enough effort to overcome the drag of the O rings. WTH? Took it all apart and put it together two or three times, and can't find anything wrong with what I see. I took the valve spool out of the piston, looked everything over hoping to find a piece of SOMETHING to justify the piston sticking in first place.
Now I'm really lost as to what to do next. I don't see anything I feel a need to replace other than seals, gaskets, and O rings. I see nothing at all to justify why I should be into the thing this deep.
I guess I'm grasping here, hoping someone has some experiences to share concerning anything similar on this style unit. At this point I'm not sure what else to do other than put it all back and hope it doesn't do that again?
It's a DK45 HSE tractor as far as I can see. The problem is this. The hydrostat decided one day to stick in the forward direction. The story as told to me, the tractor was running along as usual with no noticeable problems. Driver stops to open a gate, gets back on and can't get the range shifter to go into gear. Gears are grinding and it just won't shift. Also of note is the reverse pedal has no travel. It's pretty much solid in the neutral position.
A quick look at the external pedal links and pivots shows nothing unusual. After removing a few of the points and joints it turns out the pedals are both operating as the should, the problem is the control shaft going into the hydrostat will not move in the direction of reverse travel. Now what? I tried turning that shaft with a large Crescent wrench and decided that any more force in that direction was probably going to break something.
Searching for information on this tractor and it's transmission I find it's designed with a servo piston operated swash plate. I'm not sure how common that concept is, but my limited hydrostat experience has all been with strictly mechanical operation. I concluded that anything related to this piston mechanism is only accessed from the inside, so any work done on it means the unit come out of the tractor. I finally got the tractor in three pieces on Friday and got the unit out on the floor. Removed the two covers and exposed the piston, which was indeed stuck in the forward position. I now have the unit in another location where I have a reasonable shot at keeping everything clean while it's apart.
I did that today, and expected to find something broken, twisted, jammed, etc in either the piston/bore, or the swash plate mechanism on the inside. Following the procedure I got the pump rotating group out exposing the swash plate and found no problems at that point. Removing the plate requires the piston to be in the neutral position, so at that point I decided to give the piston a little "tap" in that direction, and it moved. Now with the swash plate out everything behind it looks normal, and the piton will go full travel in both directions with just enough effort to overcome the drag of the O rings. WTH? Took it all apart and put it together two or three times, and can't find anything wrong with what I see. I took the valve spool out of the piston, looked everything over hoping to find a piece of SOMETHING to justify the piston sticking in first place.
Now I'm really lost as to what to do next. I don't see anything I feel a need to replace other than seals, gaskets, and O rings. I see nothing at all to justify why I should be into the thing this deep.
I guess I'm grasping here, hoping someone has some experiences to share concerning anything similar on this style unit. At this point I'm not sure what else to do other than put it all back and hope it doesn't do that again?
