A little disappointed with Kubota

[fried1765]

If your nuts are seating properly, I would definitely use blue locktite to keep them tight. I had a bad nut and wheel experience because I was going to wait until 50 hours to retorque them. Luckily I caught it before the wheel was trashed. I bought new bolts and nuts, locktited them and torqued them and never touched them again in 800 hours of moderate to heavy use.

I think it is a bit too late for your advice, although it might have worked earlier.
The holes are apparently now oval shaped, and no amount of tightening or locktite will fix that.

Welding and restoring the holes to their original round seems to be the only way to do a real fix.

 

[SPYDERLK]

This is from the better of the two wheels. This nut has never loosened up. The manual say 160 ft/pounds. Every time I've checked it with my torque wrench set at 160 it'll click without the nut tightening any further. I actually loosened one then torqued it back down just to be sure. The bolts are threaded all the way so it's not like they are bottoming out before applying the correct pressure to hold the wheel on.
View attachment 590655

I think it is too late to fix this without replacement. - - Arent those cracks around the bolt hole? I have 4 Kubotas long term with that type of mounting and have no indication of any motion much less failure. Those are 16mm Gr10.9 fine threads capable of sustaining well over 250ft-lb. - Your bolts/studs may have experienced additional stress due to the cracking. - The lock washers are not a plus although I have not experienced trouble. They present two problems; 1) scarring the disk, and 2) applying the clamp force on too small a footprint, thereby adding stress to the scarred hole periphery. It would be better to have a larger OD high strength flat washer against the disk - with or without the lockwasher.

Im not sure where your trouble originated, but when you renew the setup you will start with a built in advantage if you get some 5/8" Grade 8 flatwashers from TSC and incorporate them as mentioned.​

 

[crazyal]

Let me say this again. The hole from the factory are too large. This wasn't a problem created because the bolts loosened up.

The front wheels have tapered nuts (like a car) but the rear wheels are just a flat bolt with a lock washer (two are studs with nuts and a lock washer). It's an extremely small amount of surface area to secure the wheel. Until recently they have never loosened up. To this day the right wheel has never had a bolt or nut loosen up (that's picture I posted). I posted that picture because unless you clean your wheels and look closely you may assume, like I did, everything is fine because you didn't find anything loose. On the good wheel the holes are not "egg" shaped. Adding lock tight or longer bolts with a nut on the back would do nothing to solve the problem. Again, the holes from the factory are too large.

About twice a year I check the torque on all the bolts/ nuts. It's just one of the checks I do often while greasing (but not every time I grease). But since I wasn't finding any loose I didn't examine them closely. This fall/ winter was the first time one was loose. Even then it was still snug, I just got maybe an 1/8 of a turn out of the torque wrench before it clicked. Since then I started checking it once a month. After two more months of finding bolts not staying torqued down I switched to every time I use the tractor. Over the last month and a half of checking each time the holes on the left wheel have gotten "egg" shaped. I was hoping to get through to spring before fixing it but that seams unlikely. Right now my priority is to save the good wheel (right side).

These are Ag tires. I could try to fill in the hole with weld and redrill the holes but it seams like just drilling 6 new holes would be easier. I have to believe that the axle is a machined part and the holes are precisely located. The disk is just a stamped part on a press punch and maybe it was easier to just make the hols a little oversized just in case the punch isn't as accurate. For now my plan is to try and add a thick bellevile washer. Even though the bolts ar M16 I ordered 5/8" washers with the idea the hole will be a little smaller. Hopefully the extra surface area is all that's needed to keep the good wheel from getting worse.

 

[SPYDERLK]

These are Ag tires. I could try to fill in the hole with weld and redrill the holes but it seams like just drilling 6 new holes would be easier. I have to believe that the axle is a machined part and the holes are precisely located. The disk is just a stamped part on a press punch and maybe it was easier to just make the hols a little oversized just in case the punch isn't as accurate. For now my plan is to try and add a thick bellevile washer. Even though the bolts ar M16 I ordered 5/8" washers with the idea the hole will be a little smaller. Hopefully the extra surface area is all that's needed to keep the good wheel from getting worse.

:thumbsup:The bellevilles are a good ploy because if strong enough they will be best at distributing force outward. Perhaps these would do it w/o breaking the bank:

McMaster-Carr

 

[sixdogs]

To me it looks like the rear wheels loosed up at some point and started the "elongating" issue that now continues. Once that starts you either have to replace the wheel center or do a weld and drill repair. Welding and drilling is difficult because the bolt holes are very precisely located and drilled only a whisker larger than the studs. It's hard to do that. From what I see, I'd buy new wheel centers and use the correct OEM parts. Then keep them tight.

 

[crazyal]

To me it looks like the rear wheels loosed up at some point and started the "elongating" issue that now continues. Once that starts you either have to replace the wheel center or do a weld and drill repair. Welding and drilling is difficult because the bolt holes are very precisely located and drilled only a whisker larger than the studs. It's hard to do that. From what I see, I'd buy new wheel centers and use the correct OEM parts. Then keep them tight.

AGAIN THIS DIDN'T HAPPEN BECAUSE THEY LOOSENED UP. I have removed the left wheel, the worst of the two so I could see how bad it was. The right wheel has never come off and I've only removed one of the bolts on the right wheel just to make sure that the shoulder wasn't bottomed out on the axle. To get that bolt off I had to put a cheater bar on my breaker bar because it was that tight from the factory.

If I had made the mistake of letting them get loose I would just buy the replacement parts and accept it. In fact if I had missed the bolts loosening I would feel better as I could point blame at myself and know that replacing the bad disk with a new one would fix the problem. However buying a new center disk could very well mean 8 to 10 years from now I'll be replacing them again. Also the holes in the left wheel are not egg shaped yet so I would like to prevent it from happening. However if it keeps moving they will be.

 

[Elkins45]

This may be a dumb thought, but have you considered just tack welding them? It would mean breaking out the grinder if you ever wanted to remove them, but even a few small tack welds might keep it from shifting.

 

[crazyal]

They would have to be welded to the axles. I'm not sure if I would want to potentially damage the axles.

 

[LD1]

How thick is the dish where the holes are?

I have never had an issue. Both my MX and my old l3400 had same style.

My MX dish is probably 1/2" thick. If it were mine....I'd get round holes again....either re-drilling or welding. But there will ALWAYS BE A LITTLE SLOP. You have to have clearance for the bolt to actually go through. And clearance, no matter how small, will get larger and larger with time if you cannot keep it clamped tight.

I'd countersink the two holes where the studs are, if the rim is thick enough. And use automotive type light nuts

 

[radios1]

why not just find bolts that fit fairly snug in the holes?.. countersink the holes, and use automotive type nuts. that's time tested good!.. not having that countersink is the problem..