New U-Bolts bending while tightening

Replacing U-bolts since my bump stops rotted off.

Picked up some Wheeler's u-bolts and while attempting to tighten them to 90ft-lbs (FSM spec), they have clearly bent under the spring seat.

Is this an issue...?

 

The issue is not with the bolts, its the bottom plate that’s warping and taking the bolts with it. I would replace the old bracket.

 

That's gonna be a bitch to get off.

 

Yeah thats not normal. Are you tightening them all one at a time or are you do a few turns here and there? If you run them all the way down one at a time, Id imagine that would cause that. The bottom plate has to "settle" in position as you tighten them all intermittently.

 

I've been tightening them evenly.

 

I wonder did you get a bad lot of U-Bolts

Both sides did this ??

 

That's what my initial thought was. It didn't really feel like I was cranking down on them THAT much to bend them...considering they're 9/16.

I did not attempt the other side yet.

 

This is happening because you are wrapping the plate around the axle as you tighten and it is causing the nuts to bend the u bolts. You’re going to have to get new plates as well

 

/\ YEP /\
That's exactly what's going on. From the looks of those parts, you've got some serious rust.

 

Yes, I do.

Frame and pretty much everything associated was replaced except the rear axle. In the process of refurbing my rearend.
I guess that much rust has deteriorated the bracket so much that is just doesn't have the strength it did before. Although it does feel solid.

I just torqued down the other side, going really slow and carefully doing each bolt a small bit to evenly tighten everything down, and I got to 85ftlbs with everything looking alright.

Going to disassemble this bent up one tomorrow... Trying to find a replacement plate...

If anyone did a ubolt flip and want to sell their old ones, please let me know!
Found a set

 

good time to upgrade to a u-bolt flip kit

 

That is one thing that crossed my mind, but I don't really have a need for that and I don't want to relocate shocks at this time.

 

If you cannot find replacement plates you can reinforce the ones you have. Straighten them back out, clean off the rust and weld a section of channel iron inside of them
OR
You can fabricate new ones with a section of channel iron and two pieces of angle iron cut & welded to match the contour of the axle tube.
This cannot safely be done with a single piece of channel iron but it can be done with channel iron and two sections of angle iron.

 

This was also something I thought of, but I don't have a welder nor the time to do something like that right now.

This project is taking longer than anticipated so I'd rather just spend the money on an OEM plate just to fix the issue for now.

I think it's interesting how these plates got so rusted that they've lost that much strength. I guess I shouldn't be surprised considering what some of the frames turn into. Seems like they should have been made a little bit beefier in the first place, but I won't really know how much material I've lost until I get my hands on some rust free ones.

 

I've got plates, did my flip a while ago. Lemme know if you want em

 

I don't know the exact grade and quality of the U bolts you picked up, but I would like to add something from personal welding/fabrication experience. I've had multiple semi truck drivers I've done welding for come back with a smile on their face saying things like "ah I finally found a shop that makes these on the fly, they bent me a few and made them right there! A couple of slightly tight fits, knocks with a hammer, and etc, made me realize a lot of those bolts are like cheese and not hardened obviously so the threads would get botched with little effort. I'd definitely consider the hardening of whatever bolts you buy again. If they don't list it or can't give you the specs, I wouldn't bother.

 

I've got Wheeler's U-bolts (longer ones mind you) on my truck and they don't bend at all like yours do; replace the lower bracket.