753 hub bolt comes loose

[dirtpig538]

When I use my 753 Bobcat, the left rear hub bolt loosens itself, even though I have tightened it very tight with a big wrench and a cheater pipe. What is causing it to come loose?

 

[dirtpig538]

Should I just retighten and put a couple of tack welds on it?

 

[Tazza]

Should I just retighten and put a couple of tack welds on it?

If it's coming loose, i'd suspect the key or keyways are worn out allowing it to loosen up. Really, there should be no movement allowing the bolt to loosen up when that tight.
I'd like to jack the corner up, remove the bolt and see if the hub comes off easily or not. Check for wear, clean the tapers with solvent and re-assemble if there is no wear.
You could take the bolt out, clean the threads with solvent and blow dry with compressed and, then put some loctite on the threads and tighten up, see if it comes undone again.

 

[dirtpig538]

If it's coming loose, i'd suspect the key or keyways are worn out allowing it to loosen up. Really, there should be no movement allowing the bolt to loosen up when that tight.
I'd like to jack the corner up, remove the bolt and see if the hub comes off easily or not. Check for wear, clean the tapers with solvent and re-assemble if there is no wear.
You could take the bolt out, clean the threads with solvent and blow dry with compressed and, then put some loctite on the threads and tighten up, see if it comes undone again.

I agree, there shouldn't be any movement that would turn it. The loctite is something I am going to try.. It was tightened with an 18 inch breaker bar and 4 foot cheater. I just can't see how it could possibly come loose.

 

[Tazza]

I agree, there shouldn't be any movement that would turn it. The loctite is something I am going to try.. It was tightened with an 18 inch breaker bar and 4 foot cheater. I just can't see how it could possibly come loose.

With that much pressure on it, there is no reason it shoudl ever come loose.
I'd suspect a worn key or key way. Some people put grease or oil on the tapers when assembling them, this defeats the purpose of it being used to lock the two together. It allows it to move slightly and wears the key or key way out.