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.

 

[mhart]

Now that weather is better and MMM is off, I was able to get underneath and look at this. Now that I look closer, the steps are a bit rounded. Perhaps this is the problem. The issue is that the nut spins freely as I mentioned. I assume that if I can get this off somehow, it will be an easy fix.

 

[RaydaKub]

Now that weather is better and MMM is off, I was able to get underneath and look at this. Now that I look closer, the steps are a bit rounded. Perhaps this is the problem. The issue is that the nut spins freely as I mentioned. I assume that if I can get this off somehow, it will be an easy fix.

Yeah, mine are rounded off also, and probably the stops (spring against the sides of the cam) are not in the best position. To take it off, run a socket up inside the cam. It's been over a year, but I think it was a 13mm. The spring is bolted on from the side and presses against the outside of the cam.

Sent from my iPad using TractorByNet

 

[mhart]

By Cam you mean the grey piece with the rounded edges? It will likely be difficult to get this off if the nut spins freely. Any tips on that.

 

[RaydaKub]

Yes, that's what I mean. Have you seen an expanded drawing of them?

http://www.tractorbynet.com/forums/...79-mower-height-limit-control-mowerheight.jpg
It's part 160 in the pic. The spring lever that is supposed to keep it in place is part
210 and bolts on to the V welded into the frame.

If it is too tight, you might need to pull the knob off and put a vice grips on the shaft and have somebody hold it while you break it loose from down below.

 

[mhart]

Thanks so much for your help with this.

Its not that it is too tight, the nut just spins freely and wont come off. Maybe it is stripped. Seems like it will be impossible to get out.

 

[RaydaKub]

Thanks so much for your help with this.

Its not that it is too tight, the nut just spins freely and wont come off. Maybe it is stripped. Seems like it will be impossible to get out.

Oh crap. That will make this difficult. Things are pretty tight up there, so getting tools in is gonna be a bear. The nut is almost 2 inches deep into the cam, then the cam rides up on the underside of the V bracket. On the top side, the shaft is made with a collar so that it stay on the top side. Getting at the top side pretty much requires that you take off the seat, fenders, floor pan, the whole works. Even then, grinding that shaft off is not going to be pleasant unless you have a very small cutting wheel to get in there. The shaft and nut shouldn't be terribly expensive, but that's probably not a part they have in stock because it isn't usually going to wear out. I'm sorry that you have to go through this. Mine actually seems easy now. The whole V bracket was snapped right off, but at least mine could be taken apart.

If you decide to go through with this repair, do something I didn't. Grind the lever that comes up to the cam teeth flat, and grind the cam steps flat as well.
Good luck with this!

 

[mhart]

I was actually able to get this off. I then went to the dealer and bought a new CAM and put that on. The deck holds fine at the top position but again, the knob will spin and deck will drop all the way down if I set the knob to another cutting height. Is there something I am missing?

 

[RaydaKub]

If the knob spins freely, you must have that spring tab broken, or at least bent out of shape. It only provides a detente on the side of the cam, and not a very strong one at that. Look at the picture I linked in before. That should help.

How did you get the nut off the shaft? Was the shaft ok, not stripped?

 

[mhart]

Rayda, I was able to get a better look after crawing under there and realizing that what I was spinning freely was the shaft end. I know, I am embarrassed. I was then able to get the nut off.

I thought I was in the clear when I installed the new CAM. I will try to take a look at theat spring tab tonight, it seems that is the likely problem. If it is bent, can I fix it or just get a new one.

Thanks again so much

 

[RaydaKub]

You should have been able to feel that tab push against the outside of the cam. Either it is broken or loose. Doubt it is bent, there's no way for anything to get in there to bend it.