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Discussion Starter #1
A few weeks ago I had a conversation with a leaf spring shop near me, and the subject of U bolts came up, he asked me if I knew how to assemble a U bolt, of course I said yes, he said ok show me, so proceeded to assemble it, he quickly stated nope that’s wrong.

He indicated that the grooves on the nut were actually supposed to bite into a specific side of the washer, I said I’ve never even noticed grooves of them before.

The nut does indeed have grooves and the washer is definitely not the same on each side, one side has a slight concave to it.

I thought this was very interesting and I’m just curious if any of you guys have heard of this?

This side has grooves, is not completely flat and bevels in


This side has a flat surface


This side tapers out and has less surface area


This side has a more surface area
 

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It’s hard to tell in the picture but when the nut has the the ‘biting’ surface I always put that against the surface I’m tightening to. The washers I’m not so sure of. Those appear to be stamped out of a sheet? I’m not so sure if those are what I call cone washers, just a finished and unfinished side. I always have the finished side out... IMG_3766.jpg


1992, 4.0,5 spd, BDS 4.5 heavy duty lift, jb conversions ss sye, 8.8 with ARB, Aussie front, tj shafts, dual dia.brake booster, 33” bfg a/t
 

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GREAT!
I reused my original U-bolts when I changed my springs (this is against spring manufacturer instructions). Now as soon as I am healed, I'll have to go crawl under my Jeep just to see if my nuts are on correctly.

I checked the U-bolts a couple tines in the first few months since I changed the springs and everything was still torqued to spec. I used Antiseize on the threads.
That was 5+ years ago and I'm confident that they're still tight. YMMV

Good Luck, L.M.
 
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Discussion Starter #5
I did some of my own research into this and really found nothing that could confirm this, the only thing I did find was those markings usually indicate grade C.

So was this just his best practice?, I think if it mattered a whole lot this information wouldn’t be so obscure.
 

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I am going to call bs.

The washers are a result of the stamping process, not an intentional scientific feat of engineering.

You are talking .00000025 difference on washer face.....for a leaf spring shackle......on a yj.......um, no.

This is going into the same file as fuel injector cleaner.
 

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Discussion Starter #7
I also looked at my old Crown U bolts and they don’t have the markings or any differences between the sides at all, the photos I provided are from hardware of the U bolts that were bent on site for me.

I should of also stated this wasn’t a spring manufacturer, it was a shop that replaces leaf springs on heavy trucks.
 

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I too reused the leaf spring U bolts when replacing the new springs and after cleaning, used a die to clean up the threads. The original U bolts seemed much stronger than the after market U bolts.
 

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Discussion Starter #9
This really isn’t a question of reusing old U bolts, rather it is nut orientation.

Before I was told this I have just used the flattest side and mated that to the plate, so pretty much the exact opposite of what this guy stated... I’m just trying to get to be bottom of this information.
 

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I'll help you get to the bottom.....

He's full of shit..... put the washers and nuts on and tighten em to spec... there is no top or bottom to them....
 

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Sounds like your shop guy has come up with a clever way to sucker folks into not doing their own spring replacements.
 

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Discussion Starter #13
This is the same guy that I used to attempt to fix my Mopar springs, that experience was quite odd, in the end it was just a huge waste of time as they had the same issues when I put them back on the Jeep.

I’m not quite sure if there was an angle though, as he wasn’t too excited to even have my business in the first place.
 

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To me the 3 grooves look like they may be stamped to deform the threads (Mechanical lock nut). If that is the case, they should definitely not be against the washer. They end up slightly deforming the bolt threads so you dont want to run them down the entire threads, because now all of the threads are structurally comprised and may fail prematurely.

As far as the washer goes, I agree with the previous statement. It is just how they come out when they are stamped. They're maybe some minute differences on paper but not enough to have any effect IRL. It wouldnt even make them more/less likely to loosen (look up the frictional force equation, surface area plays no part). And it isnt affecting the strength of the washer (how often does the washer fail?)

It sounds like this guy wanted to make you look dumb, but had the opposite effect. (He's probably got some washers on backwards upstairs)
 

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It looks like IRQ's #15 post gives us the info that we need.
The three marks on the end of the nut indicate grade "C".

I'm not an engineer, so all I've ever heard of is numerical hardware grades, primarily grades 2, 5 and 8. I know there are other numerical grades, but those are the most common in the auto industry.

It seems that IRQ's spring guy is a joker.

Good Luck, L.M.
 
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Discussion Starter #19
When an old guy that puts leaf springs on for a living tells you something I give them the benefit of the doubt, and I’ve heard crazier things that actually turned out to be true, however this was so out there it needed to be confirmed.

Thanks for wasting 5 minutes you will never get back ;)
 

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I don't feel my time was wasted. I learned that there's more hardware classifications than numerical grades.
Now, if I'll ever get to use that tidbit of info, that's another matter.

Good Luck, L.M.
 
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