A little disappointed with Kubota

[RickB]

Replacing the disc is a sound strategy. As a fail safe, I’d remove the paint from the hub contact area and probably the bolt/nut contact area as well. If you were to decide to forego the lock washers and substitute 5/8” hardened SAE spec flat washers that wouldn’t be a mistake as far as I’m concerned.

To answer the COO question, the tractors are built in Japan. Wheel equipment may or may not be supplied here in the US, I don’t know about that. Wheels are bolted on the tractors at either the dealership or distribution warehouse depending on how the dealer orders the tractor.

 

[crazyal]

I've got new longer bolts and nuts on order. Should be hear by next weekend. Since the bolts have captive lock washers I'll just pick up new ones. M16 and 5/8 are so close in size that washers are pretty much interchangeable and 5/8 is easy to get. The washers I've got are belleville (another name would be cone or spring washer). They are cupped shaped and as they are torqued down they flatten out.

 

[SPYDERLK]

I've got new longer bolts and nuts on order. Should be hear by next weekend. Since the bolts have captive lock washers I'll just pick up new ones. M16 and 5/8 are so close in size that washers are pretty much interchangeable and 5/8 is easy to get. The washers I've got are belleville (another name would be cone or spring washer). They are cupped shaped and as they are torqued down they flatten out.

FYI: A captive lock washer can be easily removed by grinding radially inward opposite the split until thin. Then splay open to remove.

 

[aczlan]

That's the trouble with engineering mistakes. They don't always fail, but they do tend to perpetuate themselves.
Al's bolts failed; others didn't... or haven't.
rScotty

I hate to break it to you, but John Deere uses the same design on their 310 series backhoes. The only difference being possibly the diameter of the hole in relation to the diameter of the stud going through it.

Aaron Z

 

[RoyKing]

Belleville washers are not made to be torque flat, they are made for something that changes length like exhaust and intake manifolds. From that Pic you don't have room for large flat washer, you are either going to have to make some washers or tack weld the nuts to the worn hub.

 

[SirMaxwell]

Scotty I agree. Certainly raises the question (if this was bought 'new') then why was someone dorking with the wheels? No idea how long ago the purchase was but I'd sure put some pressure on the dealer to explain this one.

Makes you wonder if the flat mating surfaces of hub and wheel are not true, and/or some substance not allowing the surfaces to stay mated. Occasionally letting the wheel shift and thus elongating.

 

[goeduck]

Makes you wonder if the flat mating surfaces of hub and wheel are not true, and/or some substance not allowing the surfaces to stay mated. Occasionally letting the wheel shift and thus elongating.

Good question.

 

[RoyKing]

We need more pics, with wheel removed, front and back

 

[bdhsfz6]

As I stated earlier, all six of the Kubota tractors I've owned use this wheel nut design and I haven't seen this problem. My father in law did have it happen though. He had this wheel movement problem on one of his tractors. He referred to it as "wheel shift". I don't remember which tractor it was. He had several Allis Chalmers and John Deere at the time. This sounds like a crazy idea but he solved the problem by thoroughly cleaning the mating surfaces of the hub and wheel. He then applied a paste containing a fine grit to increase the friction between the two surfaces. I don't remember what it was called but he said it was a product used for, among other things, bicycle seat posts to keep them from slipping when clamped.

I don't know about tractor wheels but this stuff works perfectly on the seat post of my bike.

https://www.amazon.com/gp/product/B0013VDRZU/ref=ppx_yo_dt_b_asin_title_o06__o00_s00?ie=UTF8&th=1

The product is safe for carbon fiber components and it works on steel as well. It doesn't seize and the parts are easily removable.

I'm sure there are similar industrial products on the market using the same friction principle. Might be worth a try.

 

[JWR]

We need more pics, with wheel removed, front and back

Absolutely. As prior posts by myself (and a guy who spotted the crack in the disc before me) maintain that the discs are cracked. They need to be pulled off, examined and very probably replaced. Good pictures of the (removed) discs would prove what the problem is now. How they GOT THAT WAY is another story.