The Stovebolt Site Forums The Shop Area General Truck Talk Leaf Spring U Bolts

I am installing new U bolts on the leaf springs of my '53 half ton. Are there tourque specs. for these? Also are the backing plates interchangeable, left or right? They look the same to me. Thanks in advance.

There is a torque spec but I can't remember at the moment. It will be based on the size of the thread.

The manual says "Replace U bolts to anchor plate and tighten nuts securely."

It's always good practice to check & re tighten the bolts after the first few hundred miles.
New U bolts tend to loosen a little after the first few hundred miles.

My grandpa always said to tighten till just before it starts getting looser. But then, he also said to tighten it as tight as you can get it plus one half turn. He never did offer directions on how to do either one of those priceless tips.
Carl

Installation of 48-51 rear springs (same Manual used for 1952, same instructions in 1954 Shop Manual):

Installation, step 5: Install U-bolt lockwashers and nuts and tighten to 75-90 ft-lb. other torque specs

The word "replace" is not used in this Manual. The word "new" is used in this section for replacement with "new" other parts.

Perhaps the word "replace" means to replace the part that was taken off? What manual used the word "replace"?

48-51/52 front spring installation - basically, the same procedure as used for rear springs

Yes, as long as the old U-bolts are in good condition, they can be re-used.


"Replace" simply means to put the U-bolts into the assembly, and makes no difference whether you are using good condition previously-used U-bolts, or new ones.

I don't agree with that.
For safety reasons U-bolts and nuts should always be repalced, never reused. It's not worth the risk.

Here's an excellent resource and explanation
http://www.eatondetroitspring.com/reinstalling-ubolts/
"The reason u-bolts should be replaced after they have been torque is because the threads are rolled, not cut.
Because of this the threads are distorted when torqued. This distortion will not allow the torqued to be maintained when the nuts are loosened then retightened."

Here's a video explaining the same thing:


And from a U-bolt manufacturer who also advises aginst reusing them. http://www.uboltsdirect.com/ubolts.php
"We never recommend using your old Ubolts. If you were to re-use an old Ubolt, there could be a problem when you retighten the nuts. The nut tends to grab the old threads, and these threads have been weakened because of exposure to road conditions ie. salt and moisture."

Yet another version of the same from a reputable source. http://www.acespringservice.com/u-bolt.html
"*DO NOT REUSE U-BOLTS*
*Used U-bolts will have rusted and damaged threads from the previous installation.
*A previously torqued U-bolt will suffer from distorted threads from the engagement of the deep nut. Deep nuts should be tightened once and retorqued, never loosened and retightened.
*A used U-bolt may have suffered from fatigue as well excessive stress since achieving accurate torque with commonly used impact wrenches is very difficult."


They're cheap, replace them and don't worry.

Grigg

Obviously, a U bolt manufacturer will want you to use new ones every time.

Tim, go to page 4-64 of the same manual, top of page. "Replace U bolts and anchor plates and tighten nuts securely"

Thanks.

Page 4-64 is in reference to 3/4 to 2 ton trucks, but it is not clear if "replace" means "replace with new U bolts and anchor plates".

Would you also use new anchor plates?

Nonetheless, I have always used new U bolts on my 1/2 ton trucks. Usually, one or more of the bolts would not come off without cutting the bolt.

A u bolt is a bolt bent to a U shape. The lock washers should be replaced if they are not still "spread". Other than that, you can reuse any bolt in it's former place if still in good condition. Those quotes are BS+. Rolled threads are not prone to any more "distortion" than cut. The washer keeps the nuts tight. You don't get accurate torque with an impact, that we all know. You use a torque wrench. The part about salt, road and rust is the "good condition" part. It never "hurts" to use new bolts if you have the money and if you believe they are better. IMO: replace, in a manual, means put the stuff back on, unless they use other modifying words like "new". The 55-59 Truck Manual, under "spring replacement"/removal and installation, does not use the word replace for the U-bolts, it says "install U-bolts". "Install nuts on U-bolts and tighten firmly".

Thank you, I agree completely.

As a materials engineer I can tell you that bartamos is right in calling those quotes BS, and he's correct that the statement about rolled threads is false. If the bolts are in good condition, you can re-use them. If they're not, replace them.

If there is that much distortion on the threads, then they likely will get heavily damaged when you take the nut off, or attempt to.

I hate quoting the internet. I don't trust any of it unless it agrees with me. Here is a quote from good old Wikipedia.

"Threads of metal fasteners are usually created on a thread rolling machine. They may also be cut with a lathe, tap or die. Rolled threads are stronger than cut threads, with increases of 10% to 20% in tensile strength and possibly more in fatigue resistance and wear resistance."

Well everyone is free to do what they wish, I choose to use new u-bolts for my own peace of mind and will advise others the same. The reasons previously given are all possible and logical, not always applicable given the varying conditions but possible.

Here's another slightly different good reason, the source, and unfortunately yes it's quoted form the net.. http://www.truckcomponentsonline.com/U-Bolt-Technical-Information_df_53.html

"Removed U-Bolts should NEVER be placed back onto the vehicle, they should be thrown away. Suspension U-Bolts are manufactured with a smooth rolled thread, while the mating Hi-Nuts are manufactured with sharp cut threads. When a U-Bolt is tightened to it's recommended torque level, the U-Bolt threads stretch as they mate with the Hi-Nuts. Although, not always visible to the naked eye, this damages the threads. Removing the Hi-Nuts from the U-Bolt will cause a cross-threading that will not allow the U-Bolt to be adequately re-torqued. "

Just because you could reuse them doesn't make it a good idea or as safe as using new ones, there will be some risk. I suppose some risk too that the new ones are junk.. take your pick.

If new u-bolts aren't required then what sources promote reuse of used ones and for what reasons?
And without go and no go thread gauges how will anyone know without a doubt if the threads are damaged, pulled or still in fine shape as they may appear?

All I can find are reasons to be cautious and use new U-bolts.

Again, they're not expensive so this shouldn't be a tough decision or even the debate it's turning into.

Grigg

Two slightly different views. Many web quotes. Poor little U-bolt. The Stovebolt lives on.

How about some input from the 'Real World" out there in Stovebolt Land? Anyone ever had a reused U-bolt of any condition fail?

mostly a moot point, I've never unbolted an original suspension Ubolt without it being so damaged as to be unusable, most have to be cut off .... if you can get the nut off, it must be a pretty new one, if it doesn't look badly galled [nut goes back on easily], reuse it

Bill

so I am all happy because I have brandy new stainless steel ubolts for the rear end of my latest project. I have stainless nuts, lock and flats. I decide to dry fit everything before deciding its all good. So, without using any Loctite, or anything, I proceed to test the connections. I find the bolts too long and not enough threads. In fact there was probably just exactly the right amount of threads but no more and this made me nervous. So, I proceed to remove the nuts and then I would call the stainless provider and tell him to make the ubolts shorter and with more threads to be sure there was room to tighten later.

Cant remove the nuts. You would twist the ubolt and break it off if you tried. Learn something new everyday. I had to reorder the ubolts AND nuts and start over. Stainless is a whole nother thing! I wonder if Anti-Seize and Loctite is the same thing? It really does make sense to replace your ubolts due to these issues. Just not worth the few bucks to risk it.

Stainless on stainless will gaul and lock up in a heartbeat, no surprise there. Next time use never or anti seize.

Are you sure you want stainless U-bolts? Are they as strong and tough as genuine suspension U-bolts? If you're not dead sure better stick with the proven steel ones and save stainless for when looks are more important than function.

Grigg

Deve: Are you joking about asking if anti-seize and Locktite are the same? Are you joking you were thinking of using Locktite when you had lock washers? How much was two sets of SS U-Bolts? Where did you get them custom made? Maybe I'm slow. I see you are a "restorer" so maybe you are joking? Why would you have torqued them down hard when just mocking up? Did you not send an old one or send dimensions to vendor?
"It really does make sense to replace your u-bolts due to these issues". Are you speaking of your "issue" of wrong length, no anti-seize? I would like to keep learning also, that's why I ask questions, not to be contrary.

OK Grigg, you are winning the web info by shear volume, I am out webbed. your last one has the exact words of the other in some places (seem odd?). Just give me one, I say , one web-alation from other than someone who sells U-bolts. Otherwise, I am the undisputed winner, all knowing, Inter-ballistic U-Bolt champ.

I have reused U-bolts with out any ill effects. They were not 70 year old ones, maybe four or five years old, so no damage from weather. They torqued up just as tight and correctly as when I installed them.

I believe if the nuts come right off with little effort, the threads must be OK there for the u-bolt is OK. I have changed a lot of springs on school buses and trucks and have never seen nuts and threads cross thread or cut each other like some of the quotes above talk about. They have been rusted, but some heat and a impact gun backs them right off. I would change about half due to the length and rust. Big equipment uses extra long cut to fit u-bolts, and the torch was the cutter of choice, so getting the nuts past that was difficult. If they came right apart, they went right back together.

Joe

From a truck suspension manufacturer, a manual for one of their front axles. http://www.hendrickson-intl.com/CMSPages/GetFile.aspx?guid=32c10923-6075-46a4-aab8-29a529c71d06
Page 46,

And another spring/suspension shop that's been around over 100 years, they have some nice info on more than just u-bolts.
http://www.suspensionspecialists.com/tech0004.html#2

Are there any resources that promote and explain reuse of suspension u-bolts?

Yes.
Sources:
1. Me (mechanical design engineer , Honeywell Aerospace.) (ret) I have reused many times.
2. Persons here on Stovebolt who are Material engineers.
3. Real world Persons here on Stovebolt who have not had any problems with failures and have reused U-bolts.
4. Many 4X4 Forums have the same opinions, yea and nay.
these guys are real rough on there stuff.
5. No one anywhere with actual failures of good condition reused hardware. As evidenced by the fact you still have not provided a history of failures, just people selling parts.
6. The reason I don't like the internet and don't like to quote blogs/Spring Co.'s web sites, is that if you have ever noticed, one guy will write up some issue based on what he heard in a bar or from uncle Rufus and then when somebody looks on the web to write about the same issue, they read that, and copy it and add what they heard in a bar and what their uncle Leon says. Pretty soon it's all the same words, word for word, as I've pointed out to you, and becomes Urban Legend "facts".
P.S. A person's opinion who is an engineer is not any more valuable that anyone else's. But surely as knowledgeable about mechanical hardware and materials as spring/axle company web site spiel.
No one, engineer or otherwise, would argue that a new set is not theoretically safer than old. We are not "promoting" just explaining that there is no danger in good condition hardware that will still take the proper torque values.
Let me know if you see this as constructive or you feel like it's personal (it's not). That way Cletis will understand it's a discussion not a argument/flame.

No offense taken, thanks for the discussion.

Grigg

Roger that, same here.
Thanks

I am never sure about anything I do, but I am told the U-Bolts once gone thru the hardening process has better stats than steel. I hear this from Doc at Totally Stainless, but McMaster-Carr also reports the same stats. I learned something new tho on how stainless welds itself together like that. Lesson learned!

I am still confused tho on if Anti-Seize and Loctite are the same thing. One seems to keep things looser while one seems to keep things tighter? You cant use them both.

anti seize is a nickel based grease
Loctite is a "glue" that sticks nuts to Bolts...
comes in different grades easy removal and heat/force removal...

So if I don't want my stainless nuts backing off in time? I don't do anything for any reason without using lockwashers. Never really understood the reason for liquid miracle crap in general, but now I see why anti-seize has to be used.

On the UBolts (stainless) I used, I dry fitted everything but didn't torque them. Didn't matter, apparently I got them too tight. Doesn't take much at all. I am sure they aren't tight enough for safety and yet I WILL twist them off if I remove them. THAT is why you must use anti-seize even when dry fitting. I guess anti-seize is for stainless only. Loctite is only for steel. Best guess.

Deve,

The names Anti-seize and Loctite kind of tell you what they do. You don't use Loctite unless there is no other locking feature. Locktite works best on real small hardware, in high vibration environments, that you can not torque very much or you will break it. Or, as I said, where no other locking feature is possible. It causes more trouble than it's worth if you can use any other mechanical method. (IE: parts have to be clean of grease and oil, and maybe cured, can't use near moving parts) Our trucks never had it or needed it. It is totally avoided in many industries and never used on access covers or maintenance items.
You use anti-seize usually on SS and some places where dissimilar metals are fastened together or you will get, as Grigg said, galling/seizing/cold welding. Use Moly Lube, don't over torque and don't use air/electric drivers with your SS bolts... and don't use SS to begin with!

I have been very impressed with the stainless hardware I get from Totally Stainless. Its just that I have never used Loctite, anti-seize or anything before this. Torque things properly and use the appropriate lockwashers and that's the end of it. Its another story with stainless so it caught me off guard. Thanks all!

I've seen enough old stuff break that I will go with new every time.

Just for kicks, go to your local spring shop, we have some 100 year old shops here in KC, and watch them build u-bolts. Its nothing more then a threaded rod bent in a giant press, nothing special about it.

I used to drag race for years, I seen just about everything you can think of break, except a U-bolt!

Joe

I guess Smith and the others who always put new on must buy their lug nuts and wheel studs by the case. Just kidding.

I did replace mine on my '50, but that's because they broke.
They were so rusted I decided to use an air wrench. When one let go, it scared the heck out of me. What a racket! I bought my replacements at a trailer sale and supply outfit. Relatively inexpensive.

Some anti-seize is copper-based (Kopr-Kote) as well.


Out of curiosity, why are you so adamant on using stainless hardware anyways? Stainless U-bolts seem very unnecessary and have too many "What-if's" for me.

I've only ever had issues with steel u-bolts when unbolting, and if they're damaged or break you replace them.

I once wrote and tried to explain, that SS or Grade 8 is never necessary on our trucks. I was slammed, tarred, flamed, extinguished, flamed again, and run off. The post was locked and then deleted. So I have no comment. I want to live in peace.

Hardened stainless can be as strong as grade 8 or better. What drives me to search for preservatives for these trucks? Why would anyone choose totally rust proof fasteners, non-magnetic, that looks almost exactly like the now (extremely hard to find due to new EPA regulations)cadmium plating that was original to the trucks? The answer is now that they come in button head (looks VERY much like original except rather than clutch head, they are allen head) it makes enough sense to do. Stainless suppliers have really picked up their game. You can get grease zerks as well as most brake blocks and unique fasteners ALL in stainless.

You can get a free catalog from Totally Stainless and then you will have educated yourself on what's out there. McMaster-Carr also has a great selection. Bart is pretty much right on the most these trucks need is grade 5, but what invariably happens is, people go out and purchase grade 5 bolts but forget to get grade 5 nuts to go with them.

In my case, to be honest, my restorations are so intricate and OCD over-the-top that I have to catalog ever single nut, bolt, fastener and small part on the truck, then decide on which material is best for this restoration. The one I have been working on for over a year now is a stainless project. I use 3 different grades of stainless depending on the strength needed.

The U-bolts provided by Totally Stainless use grade 8 equivalent material (a little better). All you have to be sure to remember to do is put anti-seize on the threads. Something I learned the hard way.

I just got done putting a disc brake conversion on this project and the front suspension bolts are ARP bolts that I got from Totally Stainless. Very nice stuff all around. Polished, clean looking, and very strong. So you don't have to ever give that hardware connection another thought for the entire life of the truck.

It doesn't have much to do with what is 'necessary'. What is your comfort level when it comes to several things a lot of people don't consider.. for example..

1) Is the steel strong enough to meet or exceed the manufacturers spec?

2) What is the durability of the plating that is used and will it have the longevity to meet or exceed your expectations for years to come?

3) Since restoration is more about preservation than anything, how far would you go to ensure that particular hardware connection is ONE AND DONE? In other words, will the paint and substrate fail first or associated parts?

4) If you are spending on high dollar epoxy primer, then urethane high build primer, then sealer, then topcoat costing upwards of a few thousand dollars then why would you use period incorrect zinc plating on over the counter steel bolts? Hats off to the restorers that use original bolts and have them actually CAD plated, but I cant find a CAD plater anymore, and stainless is better in the long run.

If I sound opinionated, I absolutely am. Many years as a Kansas farmers son working on these trucks with bailing wire and duct tape. Nowadays, I look for more refined ways. All while having a BLAST doing it!

For decades I have used a philosophy that has worked well for me, "when in doubt, swap it out".

I have used these guys many times. They sell a good American product and run a good business. Prices are good as well. No affiliation, but I don't hesitate to acknowledge superior performance.

http://www.stengelbros.com/

oops, did I say never? Sorry, I meant never. As far as doubt, when I decide the fastener is still in good condition and it takes the torque and I use a new lock washer if it's "sprung", there is no doubt. I got shoes older than these trucks.
"I use 3 different grades of stainless depending on the strength needed", WOW! that is OCD!, but I call it CDO because it needs to be in alphabetical order for me.