Idiot needs help recovering from ruined front wheel

[bitseeker]

I screwed-up and would like some advice.

I failed to notice that all six studs on the front wheels of our 4WD 5240 had backed out of the hub enough to allow the wheel to drop off of the centering and load-bearing projection on the hub. My oversight caused the wheel to crack and the six holes in the wheels to be elongated. The wheel and studs are toast. I will also replace the lug nuts.

What's odd is that none of the lug nuts loosened, just the studs backed out of the hub. I'd like to think that the unchanged exposed stud threads outside the lug nut caused my oversight, but is was plain stupidity. I blocked up the front and was able to remove all six studs and get the wheel off (loaded tires are HEAVY!). Looking at the hub thickness, it seems much fewer threads are in contact with the hub than in contact with the lug nuts. Unless there was something restraining the studs in the hub, like loctite or a jam-nut on the inside of the hub, it seems as though the studs would always come out before the lug nuts come off. It could be that there were, or were supposed to be, jam-nuts, but there were none. The studs are 14 mm X 1.50 x 57 mm.

I looked at the Kubota Workshop Manual and the hub to stud connection is not shown or discussed anywhere I could find, so I do not know if there was anything restraining the studs in the hubs. I can't see the back of the hub on the other side for comparison.

How should I re-install the studs to keep this from happening again?

Thanks for your help.

 

[TripleR]

Sorry I can't help, but will be interested in what you find out.

 

[bitseeker]

Thanks TripleR,

I am confident that someone on TractorByNet will know.

If I find the answer elsewhere, I will post that.

 

[Poopdeck Pappy]

I'm glad that didn't happen when you were rolling down a paved road at 18mph. That could have been . . . umm . . . interesting.

I once had a tie rod nut fall off just when I pulled into a driveway after driving a tractor down the road at full road speed. The front wheels went all cockeyed. I've often wondered what would have happened if that nut had fallen off 30 seconds earlier.

 

[bitseeker]

I had the same thought as you did about what could have happened. Not pretty!

What's worse is that there were many indications of trouble before I finally noticed the true cause. The ride seemed rough on the paved driveway. Without looking, I attributed the rough ride to cold weather and the tires having sat for a few days developing flat spots. Secondly, I noticed that wheel was tipped out at the top, and assumed that it had always been that way. I centered myself in front and looked to see if the other front wheel had the same angle. The wheels were turned to the side some, and I figured it was built into the steering geometry.

You can bet I'll be lots more diligent in finding the cause of future vibration or odd appearance.

I want to understand how the studs were able to tread out of the hub and make that less likely to happen after the new wheel is back on the tractor. I am wondering if over-torquing the lug nuts could have loosened any loctite type thread-locker at the hub and galled the lug-nuts to the studs. I had to split a nut to get it off the stud, and both the stud and lug-nut were galled at the wheel end, locking them together.

 

[Arc weld]

It's highly possible it wasn't assembled correctly at the factory but if it was loose for a while anything could have happened.

 

[Stick895]

What does it look like on the other wheel? Or on similar tractors on the dealers lot?

 

[PILOON]

I have had similar event always with my frt right.
In my case it was caused from angle snow plowing that was causing the frt rt to skip/grab in the crabbed position.
The slip/grab tended to unscrew the lug bolts.
I saved my rim by making a backup plate from 1/4" stock (like large washer) and using longer bolts to mount.( I used the good rim as a drill template.)

I'd suggest that using 4WD on pavement might just be the cause of loose frt rim attachment as the frt leads the rears by as much as 5%. That plus improper torque.

You have studs so the proper repair would be to use helicoils to repair the drums, new studs and new rim or as I did weld a backer plate on the rim. (actually plate should be on front so as to sandwich the rim to the drum)

 

[JJZ 109]

Looking at the hub thickness, it seems much fewer threads are in contact with the hub than in contact with the lug nuts. Unless there was something restraining the studs in the hub, like loctite or a jam-nut on the inside of the hub, it seems as though the studs would always come out before the lug nuts come off. How should I re-install the studs to keep this from happening again?

Thanks for your help.

It it possible that the threads on the hub side are opposite of the lug nut side? As in left handed thread on the hub and right hand for the nut?
You've taken the thing apart so you know what you're looking at. I guess I haven't seen a threaded in stud. Any of the automotive type I've ever taken apart have been the type that are driven or pressed in from the rear of the hub. But if yours are indeed threaded I'd definitely reassemble with some sort of thread locker.
Let us know how you make out in the end.

 

[Gary Fowler]

That is weird. Never heard of that happening. My tractor (LS) has only two lug nuts (studs in the tractor hub) and these are used for mounting the wheel and alignment to the hub ring. The rest are lug bolts. If your tractor has all studs embedded in the hub, I would put some blue Loctite on them when you replace them to keep them in place. The problem with that is it would be hard to remove them if needing to replace if you do, but they shouldn't back out again.

I think a better choice would be to do like my LS wheels and just put in two studs 180 degrees apart in the hub to align the tire with(use Loctite on these) and then use lug bolts to secure the remainder with. You can easily see if a lug bolt is loosened.

Another thing that you could do after tightening it to put a diagonal mark across the nut (or bolt) and extend it on to the rim using a metal paint marker or even a permanent ink marker. If the lines then become broken it is obvious that it has loosened off and needs tightening.