U bolt vs axle tube diameter

[RODRIG3911]

So do you need to buy smaller diameter U bolts if you upgrade your rear housing?... Early Broncos came with 3 1/4" axle tubes from the factory. My WH super 9 has smaller (but stronger) 3" diameter tube. With the smaller tube I'm thinking I may need smaller U bolts. Mine come loose easy and I actually just snapped one trying to torque it to specs

 

[DirtDonk]

To be "perfect" you would use a u-bolt made for a 3" housing. But even the largest 5/8" diameter u-bolts made for the 3.25" housings work perfectly fine with the smaller 3" tubes.
We've tried it with different bolt diameters and it always worked.

So if you happen to have a new set that are made for 3" tubing, by all means go ahead and use them. If you only have your previous u-bolts made for the EB housing, go ahead and use them in good health.

While it's often recommended to replace u-bolts after every use, I've never subscribed to that practice with anything but either stock originals, or compromised u-bolts. If your old ones are in great condition with no thread damage or obvious deterioration anywhere, or are larger anyway, I'd have no problem re-using them at least once.
I would not re-use them more than 3 times perhaps, but that's not scientific. Just my own practice.

The exception might be the nuts. Whether they are of the Nyloc type, or of the C-nut persuasion, if they are getting loose, just get new ones.
If they are the tall non-locking type, never use an impact gun on them. I've seen way too many of them over-torqued to the point of damaging the threads.

Paul

 

[RODRIG3911]

Thanks Paul! I snapped one so I need to replace then anyways. If I find 5/8 by 3" would I be able to use them with a spring plate made for 3.25" bolts. In my mind I'm thinking I'd only need to pull each U bolt out 1/8" on either side of the plate. I just wonder if it'll torque down straight that way. If not, I'll buy the larger 3 1/4" U bolts to work with the plates I already have

 

[DirtDonk]

Yeah, the U-Bolt plate is a different story. You might be able to spread out the five eights inch u-bolts if you need to, but it's extremely difficult. You'd probably be better off filing out a little of the hole in the top plate.
You are talking about a really big thick heavy duty top plate, like our extreme set up. Correct? With 5/8” bolts it must be extra thick and strong.

 

[RODRIG3911]

Yes sir. I still have my top plates from when I was running your HD 5/8 Ubolts and plates. I think I'll try 3" bolts and grind the holes a bit on the top plates if necessary

 

[DirtDonk]

That works. But just so you know weÂ've tried the 3 1/4 big bolts on the 3 inch axle tubes many times and theyÂ've worked perfectly. Once theyÂ're torqued down itÂ's almost like you canÂ't even see a gap at the center of the tube. Much less than an eighth of an inch on each side!

 

[RODRIG3911]

Thanks Paul! I appreciate all the knowledge you give us on here. You've been helping me with mine for almost half my life now haha. If I ever get to meet you at an event I owe you some cold beers ;D

 

[Broncobowsher]

If you have a local spring shop bend up the U-bolts they might be able to stop a hair shy. This way you can use the 3" mandrel to match the axle tube but the tips spread just enough to fit the retainer plate.

 

[RODRIG3911]

If you have a local spring shop bend up the U-bolts they might be able to stop a hair shy. This way you can use the 3" mandrel to match the axle tube but the tips spread just enough to fit the retainer plate.

Good point! Going to Arizona Spring on Grant early this next week to have them build be a set of 5/8" U bolts