Cracked disk on an L4740

[Schmitty]

Howdy guys and gals,

I had/have a bit of a wobbly wheel situation. I purchased my tractor with 1950 hours on it in Spring of 2018 and noticed some cracks around the right rear wheel bolts at the time of delivery. I have been keeping an eye on these and yesterday noticed they had gotten a bit bigger. Today my brother informed me that my wheel was wobbling as he as walking behind me.

We got the tire in the air and confirmed that just the wheel is wobbling, not the whole axle. When we went to loosen the bolts he was able to break them without much effort, and he's about 150lbs soaking wet...so they probably were not torques to spec (130-140 ft-lbs I recall).

So, would loose bolts cause this issue? Hopefully the picture works...I may have too few posts to include images.

Also, the left disk is just fine and has no sign of any cracking, new or old.

 

[fruitcakesa]

Loose lugs can cause such cracks.
My old L 4630 had similar cracks on one rim, cause unknown.
I ordered a new disk from Kubota

 

[200mph]

Besides replacing the wheel disc, I'd look closely at the studs/bolts and lug nuts to make certain they are not damage and proper fastener torque can be applied.

The wheel disc is approximately $215 (using Messick's as source)

 

[Yooper]

You can see where the bolts/nuts were loose by the wear pattern in the wheel. Definitely replace whatever fasteners that are used to secure the wheel.

 

[Dave_eng]

Check all wheels for nut torque.

If any others found loose examine very carefully for cracks.

Do NOT weld on any wheel with a tire on!! Google pyrolysis.

https://www.ihsa.ca/pdfs/safety_talks/tire_explosions_pyrolysis.pdf

Dave

 

[Schmitty]

Thanks all. There's a new disk on the way, just 3-5 business days to my local dealer, hopefully. Now's a good time to get this tire tubed, since it will randomly lose air.

I'll definitely take my torque wrench with me when this gets reinstalled and check the left side as well.

 

[BigG]

Check all wheels for nut torque.

If any others found loose examine very carefully for cracks.

Do NOT weld on any wheel with a tire on!! Google pyrolysis.

https://www.ihsa.ca/pdfs/safety_talks/tire_explosions_pyrolysis.pdf

Dave

I saw the utube, https://www.youtube.com/watch?v=uQbKCd3ezrA, and thought about the long thread where you were talking about welding on a tire rim. Some people were not sure that the tire would explode but here is another reference to the problem in layman's terms.

Thank you for sharing your knowledge with us.