MMM adjustment knob

[mhart]

I have read some of the threads about the MMM adjustment knob under the seat. It has been problematic at times, sometimes having a hard time getting it to rotate to the "top" setting. Generally, I can get it to work.


Yesterday I went to mow. I set it at 3.5 or so. When I went to lower it, the mower went all the way down and it spun the knob quickly down to the lowest setting. I now cannot get the settings to hold, it always rotates the knob on its own when I lower the mmm.

Any help appreciated.

Thanks
Matt

 

[TripleR]

Check with RaydaKub, he has experience with working on them.

http://www.tractorbynet.com/forums/kubota-owning-operating/222715-mower-height-limit-control.html

 

[RaydaKub]

Check with RaydaKub, he has experience with working on them.

http://www.tractorbynet.com/forums/kubota-owning-operating/222715-mower-height-limit-control.html

I guess I've got my little niche of heaven carved out here, eh? :laughing:

I don't know if they are all the same or not. I have a BX2230. Mine was broken right off the frame.
The knob rotates a shaft that goes through this bracket, then there is a large cylinder with several steps on it. Each step is one of the settings, but they all get the same cam resting against the given step. I noticed that the cam on mine was rounded off a little bit. I didn't fix it, but I maybe should have. Maybe yours is rounded off even more and slips off. Anyway, inside this cylinder is a nut. If this nut is too loose, it could allow the whole knob to turn too easily and if you tighten it down, you can't move the knob at all. If I recall, it was a 15mm nut, but don't hold me to that, might be 13. Needed at least a 4 inch extension on the socket to fit up in there.

As TripleR noted, look at my thread. If you pull up this picture

http://www.tractorbynet.com/forums/...79-mower-height-limit-control-mowerheight.jpg

you can see the cylinder as part 160 and the nut as 180. The cam that sits on each of these steps is shown on the horizontal shaft right between the arrows for parts 210 and 220.

Hope this helps!

 

[mhart]

Thanks so much for this information. I just got a chance to look at this again. I located the nut you are referring to. I was able to spin the nut with my finger continually. It did not seem to want to tighten at all. It is really hard to get a good look at it.

Given thiis scenerio, what would you do next. It is really annoying not being able to lower the deck to a certain level. I was also thinking, I am able to get the deck to lock in at the "top" setting. It is sometimes difficult to get the knob to turn into this setting for some reason, but when I can get it into the top setting, the deck will hold there. It just wont hold at any of the other levels. When I try it, the knob spins rapidly and the deck goes to the lowest level.

Thanks so much for any help

Matt

 

[RaydaKub]

The spinning nut has me concerned. If you can't tighten this up, you likely can't remove it either; it sounds like it is stripped.

There is another piece to this puzzle also. There is a small flat bar that provides spring tension against the stepped spool. Notice that the spool in the picture has squared off sides. The intent is that the tension is increased as you rotate to the next setting, then relaxes to "normal" tension once the next flat side comes into position. These are represented by part numbers 210 and 220. So even if the nut isn't tight, this bar should at least slow it down from turning. Maybe with the nut being loose, the spool isn't held in place well enough that this bar is touching the sides.

If that nut is totally stripped out, that whole shaft is gonna be a bugger to get out. Perhaps you'll need to add some tension by pulling vertically on the shaft and try to unscrew the nut to get it all out. The other option might be to try to grind off the flange about 2/3 of the way down the shaft and let it drop all the way through. It's not gonna be pretty though. Or grind the whole thing right off. Any of the 3 methods, it sounds like this shaft and the nut will need to be replaced.

 

[beckmurph]

I believe you have a bXX20? I had to take mine back to dealer to have fixed. I was mowing along last summer and every thing was fine, then I was mowing dirt. The deck had dropped to the ground. Kubota replaced the parts on the deck and I attempted to fix it my self. But I could not get it to hold the deck in place. Took it back to the dealer and they fixed it. Mows fine now.:2cents:

 

[mhart]

My deck will hold up at a position when using the 3 point lowering lever. Therefore, I can mow with it, but if I go to raise the deck and lower it again, I can never be sure that I lowered it the level that I had it at previously.

However, if I set the deck to a certain level using the adjustment knob, then use the lowering lever/ push it all the way down, then the deck will not hold at that desired level.

That being said, the deck will hold at the "top" position, even when pressing the lever all the way down. I dont understand why the deck will hold at the top, but not hold at the other levels.

 

[RaydaKub]

Can you reach up under there and see if the steps or the bar that is supposed to hook on the steps are rounded off? I know you said the nut was loose, does the spool wiggle around at all?

 

[mhart]

I did look again, does not appear that the steps or bar are rounded off. Spool does move slightly but nothing major. Tried again with the nut but it continues to spin.

 

[RaydaKub]

Man, I don't get it... I guess I would drop off the mower and crawl underneath with a trouble light. Set the limit to 4 and see why it doesn't catch on the 2nd step (top seems to work). Then have somebody turn it to 3.5 and see if it catches on the 3rd step. You should be able to lift the arms easily while somebody else turns the knob. There has to be some reason it doesn't seem to catch.