Reuse U-Bolt Nuts?

[Dzimm]

So I know it's not acceptable to reuse u-bolts but is it okay to reuse the nuts?  

 

I'm asking because I need to remove the leaf springs on the truck to swap some of the leaves.  I have new D35 u-bolts already but I cannot find just the nuts anywhere (possibly due to search terms), because of this I was looking at new u-bolts and came across a few that didn't come with nuts and the description said to reuse the nuts.  This got me thinking. 

 

The reasons always given for not reusing the bolts is that it's torque to yield and that the nut has sharp threads that cut the rounded ones on the bolt.  The bolt is what stretches when it's tightened and the bolt threads are what are damaged, so it seems that the nuts should be fine to reuse.  

 

What is your guys thoughts?  Or can anyone point me to new nuts, preferably the tall ones, that don't cost as much as a whole new bolt kit?

[MeanLemons]

I reuse my u bolts all the time. Never had problems. 

[AZJeff]

I know that many people reuse u-bolts all the time, but all the spring shops I know of say it’s not a wise practice, for reasons Dzimm noted.

 

reusing nuts should not be an issue, since it’s the bolt that yields, and not the nut, when the torque is applied.

[Dzimm]

Yeah there seems to be quite a few people that say they reuse bolts with no issues and there is a lack of evidence in that being the cause of any issues.  It's a peace of mind thing though to do so as something could happen, then again, something could happen with new bolts.

 

I'll just reuse the nuts then (temporary anyway) assuming they come off easy.  Just wanted to get some other points of view.  Thanks!

[schardein]

These days my budget allows for new u-bolts on my projects.  But that wasn't always the case.  I think that the condition of the u-bolt and nut can be a guide here.  I've pulled some axles at the junkyard where the nut came loose fairly easy and u-bolts were basically rust free.  Others, The u-bolts are rusty and the nut fights you all the way off, screeching every time you turn it using all your strength on a 18" breaker bar haha.  I don't re-use those... these days I just cut them off.

 

If the u-bolts are still relatively new, I wouldn't (and haven't) had a problem re-using them.  I would re-check the torque after the first drive, and then again at, say, 50, 100 and 500 miles.  

 

On a related note, I've seen some factory spring plates that are distorted at factory u-bolt torque levels.  I recently replaced the spring u-bolt plates on my CJ with thicker ones from Barnes, along with larger than stock diameter u-bolts (5/8" versus 1/2").  The stock CJ plates were distorted, and I had problems with the u-bolts seeming to get loose and require re-torqing.  The larger/thicker parts solved that.  I'm in the process of putting together a MJ Dana 44 for my MJ, and the stock D44 spring plates are distorted.  I will likely replace them, I see that Rusty's offers a hd replacement.  I mention this because if you find the u-bolts seem to require re-torqing, maybe it isn't the bolts so much as the spring plates that are the problem.

[Eagle]

I am not convinced that the rear axle U-bolts are torque to yield. The head bolts are, and even those can be re-used once. The FSM for the 2000 XJ calls for a torque on the rear spring U-bolts of 52 ft-lbs. Those are 12mm U-bolts, with is pretty close to 1/2". And the torque on the 1/2" wheel studs is around 100 ft-lbs, and those aren't considered torque to yield. The MJ U-bolts were 14mm. I reused them when I removed the rear AAL from the red '88, and I'm sure the previous owner reused them when he installed the AAL. I haven't experienced any problems and I don't expect to.

 

I also reused the factory U-bolts on the 2001 XJ when I rebuilt the rear springs when one of them broke a leaf.

[Eagle]

3 minutes ago, schardein said:

On a related note, I've seen some factory spring plates that are distorted at factory u-bolt torque levels.  I recently replaced the spring u-bolt plates on my CJ with thicker ones from Barnes, along with larger than stock diameter u-bolts (5/8" versus 1/2").  The stock CJ plates were distorted, and I had problems with the u-bolts seeming to get loose and require re-torqing.  The larger/thicker parts solved that.  I'm in the process of putting together a MJ Dana 44 for my MJ, and the stock D44 spring plates are distorted.  I will likely replace them, I see that Rusty's offers a hd replacement.  I mention this because if you find the u-bolts seem to require re-torquing, maybe it isn't the bolts so much as the spring plates that are the problem.

 

Good point. The MJ spring plates had a hat-shaped reinforcement bracket underneath it to help address that issue. A lot of people leave that off when they work on the rear suspension. (And, I think I remember someone saying that Jeep stopped using that for 1991 or '92.)

[schardein]

Just now, Eagle said:

 

Good point. The MJ spring plates had a hat-shaped reinforcement bracket underneath it to help address that issue. A lot of people leave that off when they work on the rear suspension. (And, I think I remember someone saying that Jeep stopped using that for 1991 or '92.)

IIRC, my axle came from an 89.  I got the spring plates and the hat shaped reinforcements.  But both pieces are distorted, on both sides.  Also, one side the shock stud is bent, so I either have to repair that also, or just replace them.

 

The truck wasn't wrecked, but I paid the place to remove the axle for me as I was working long hours at the time.  So perhaps the damage was done then?  But based on what I've seen on my CJ plates and some XJ plates, it's not an uncommon thing.

[Ωhm]

Short read on reusing nuts. Check out the section: Re-use of Fasteners and Torque

[AZJeff]

6 hours ago, Dzimm said:

Yeah there seems to be quite a few people that say they reuse bolts with no issues and there is a lack of evidence in that being the cause of any issues.  It's a peace of mind thing though to do so as something could happen, then again, something could happen with new bolts.

 

I'll just reuse the nuts then (temporary anyway) assuming they come off easy.  Just wanted to get some other points of view.  Thanks!

To make sure the nuts don’t come loose, beat the free end of the threads to distort them.  It’s like hillbilly nut staking.

 

I hope you realize I am kidding, of course.

[cruiser54]

I'd rather reuse factory parts, like I have for 50 years.

Only ever got new u-bolts when doing a lift or something where they were too short.

 

Also, what's "new" anymore?

Shiny reverse engineered chinese crap? Look at the failure rate of the chinese stuff!!

They don't care about our safety. Hell, they've poisoned baby food, dog food, put lead in paint.