Leaf spring U bolts torque spec

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Is it OK to loosen and re-torque? Reading elsewhere that the clamping force will not be right if you already overstressed them. Also saw some discussion of the way the threads lock they can be retorqued to increase but should never be re-used once backed off. I know my rusty old bolts need replaced, but seeing posts here about ones that were impacted on and wondered if they should be replaced. Or is that just hype from people that want to sell bolts?
Also what's a good source for new bolts. I have 7-1/4, so they are only 7/16". A lot of the bolts I see available are plated, not black like I believe originals were. Does anyone know for sure what is correct grade? I would think that could make a big difference in torque, clamping, spring movement...
 
RustyRatRod said:
Wasn't meant as "venomous" it was only truthful. I cannot help it if people who are supposedly into Mopars do not own and read perhaps the two most important books ever written about them. It's complete ignorance to me. Much like anyone who owns a Mopar, but does not have the factory service manual. It befuddles me. Then on top of that, those same people question ME about something that not only is confirmed in the Mopar manuals, but in a lot of others, plus confirmed with my own experience. Instead of a smug "I doubt that", it could have been "Hay Rob, how bout a reference?" But you had to put a dig in first and it's not the first time for you. Your "I doubt that" discounted all of my experience. Period. I should have told you to F off, but I explained myself instead and you call my response venomous. Lemmie tell you buddy, you ain't seen me get venomous. Yet. I gave you what you asked for. A reference. You don't like my delivery? Then think about your response next time.
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Lighten up dude. We,re all Mopar brethren.
 
daredevil said:
Lighten up dude. We,re all Mopar brethren.
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I hear you and I understand. But let me ask you.

What do you KNOW like the back of your hand? How would you feel if not just one, but several people kept telling you that you were wrong about it when you knew you were right?
 
zkx14 said:
is it ok to loosen and re-torque? Reading elsewhere that the clamping force will not be right if you already overstressed them. Also saw some discussion of the way the threads lock they can be retorqued to increase but should never be re-used once backed off. I know my rusty old bolts need replaced, but seeing posts here about ones that were impacted on and wondered if they should be replaced. Or is that just hype from people that want to sell bolts?
Also what's a good source for new bolts. I have 7-1/4, so they are only 7/16". A lot of the bolts i see available are plated, not black like i believe originals were. Does anyone know for sure what is correct grade? I would think that could make a big difference in torque, clamping spring movement...
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x2
 
Thanks for the info Rusty... Clearly I have over tightened my u-bolts.. So I too am interested in whether or not they can be relaxed and re-torqued
 
I've seen tossed around that they are not supposed to be used more than once. My take on it is, as long as you can get the nuts loose I would reuse them. If you have over tightened them, here is how "I" would retorque them.

Jack the car up and support it on jack stands on the frame rails. Loosen the U bolt retaining nuts. As long as they will break loose and spin off almost or hand loose, I would say they are safe to reuse. If they are tough to turn backing off, similar to a self locking nut, or worse (and they probably will be) I would not recommend reusing them. This is just my opinion, use your own judgment.

Providing they come off good, here is what I would do. Back the nuts off and remove them completely. Have some RTV ready and smear some inside each nut and on the threads of the U bolt. I like doing this because U bolt nuts are notorious for rusting badly and this will help you remove them in the future if you need to.

Start each nut and tighten them in a crisscross pattern, tighten them to 45 LB FT. It is fine to do this with the weight of the car OFF the rear wheels. Since the springs slip between the shock plates, this is one of the few times it is ok to torque suspension bolts with the wheels in the air. There ain't many and this is one of them.

If your springs have been together for a while, it might even benefit you to completely remove them, disassemble them leaf by leaf and replace the plastic bushings between each spring and reassemble them. Those bushings are there to help the springs slip back and forth on each other. If they are worn or missing, or the springs are rusted all to snot and back it can cause the springs to bind. If that's the case, I suggest cleaning them up and painting them with something like the Rustoleum oil based paint. It's cheap from Home Depot.

Once you've done all that, carefully reassemble the spring packs and put a little grease on each plastic bushing. Disc brake wheel bearing grease works good. Just a little dab.

Once you get all done torqued and back together, lower the car on its wheels and bounce the rear of the car up and down several times to settle everything out good. That should do it.

My apologies for comin off like a asshole earlier. This is just something I have done a BUTTLOAD of with both cars and OTR trucks. I have wallowed around in mud under port a potty trucks with "stuff" dripping all over me removing, reconditioning and replacing leaf springs for a lot of years. It was one of the first jobs I had. Been to school on it even. Got some little bullshit certificates on it somewhere around here. So, when everybody was doubtin it, I kinda got bent outta shape. Forgive me.

As far as reusing the U bolts, technically, I don't believe you're supposed to do it. But my opinion has always been that if they come loose real good, they are ok and I stand by it. Done a buttload of them that way and never had any trouble.
 
Rob, thanks for the reply on the bolts and the added info on rebuilding the springs. Will need to do that if I don't replace them. Keith
 
I know I've already posted this on another thread, but Rusty appears to be right on the money. When I re-torqued my bolts down to a 'lesser' 45 lbs it did seem to improve the ride. I realize it may have seemed like some folks were disrespecting good advice, but it did provoke a better definition of why things work the way they do. It made me think more about the plastic I installed years ago in a front traverse leaf assembly on a T-bucket. Obviously those leafs were meant to slide. So I guess that anything done (like over-torquing u-bolts) to impede that movement would screw things up. Thanks Rusty.
 
Rusty, Thank You for your well thought out answer. I too have one of those MP performance manuals from back in the mid to late 70's. Looks like I need to get it out and reread and learn what i have forgotten. And I also need to fix my u bolts since I used the old impact on them. Thanks Again.
 
Glad I could help. Trust me. If it weren't for screwin up, I would know nothing.
 
Had some free time yesterday so I loosened and re installed my U bolt nuts to the proper torque.
 
Coolness. I bet you will be able to tell a difference.
 
Do they sell the U-bolts with the flatted saddle for the axle tube? I remember for a while there they were just bent rod and no flat! I think that's why I reused my old ones!

I rebuilt the springs on my 66 with new pads and steels, hope I gave em a shot of grease but I doubt it!! Doh!! Good info here, thanks Rob!
 
cosgig said:
Do they sell the U-bolts with the flatted saddle for the axle tube? I remember for a while there they were just bent rod and no flat! I think that's why I reused my old ones!

I rebuilt the springs on my 66 with new pads and steels, hope I gave em a shot of grease but I doubt it!! Doh!! Good info here, thanks Rob!
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:-D I will definately loosen and check, retorque after reading all this, beleive that rusty knows about this after reading all of it. but I always tightened them "farm tractor tight" on the old hemi car, have seen pics w/ the rear part of the s.s. springs spead like eagles wing feathers, never had any strange popping or anything. the hemi was prob. too loud to hear it anyway, and there was alot that happened when I dropped the hammer on it. wheels usually about 6 to 10' off the ground till second gear change, when there was a little bite. rusty, don`t get offended so easy,(pot callin the kettle black here) there is a lot of guys makin statements on here that don`t know squat about what their talkin about, we just have to read between the lines and make up our own mind. nuff said on my part!!!!!!bob:coffee2:
 
famous bob said:
:-D I will definately loosen and check, retorque after reading all this, beleive that rusty knows about this after reading all of it. but I always tightened them "farm tractor tight" on the old hemi car, have seen pics w/ the rear part of the s.s. springs spead like eagles wing feathers, never had any strange popping or anything. the hemi was prob. too loud to hear it anyway, and there was alot that happened when I dropped the hammer on it. wheels usually about 6 to 10' off the ground till second gear change, when there was a little bite. rusty, don`t get offended so easy,(pot callin the kettle black here) there is a lot of guys makin statements on here that don`t know squat about what their talkin about, we just have to read between the lines and make up our own mind. nuff said on my part!!!!!!bob:coffee2:
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Did I post something that offended someone??
 
Went ahead and double nutted the U bolts for grins and giggles.
 
I replaced the rear springs on my wife's 73 Dart 2 months ago. Torqued the bolts to 45 after reading a post by RustyRatRod.
 
An old thread that needed to be resurrected. I'm going to break out the MP Performance manual and re-educate myself... thanks Rusty.
 
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