Where to use/not use Anti-Seize

[ntsqd]

Got to thinking about this.

So use it everywhere that doesn't require thread locker? Won't the anti-seize make the bolt / nut more prone to backing out or am I missing something completely?

The way that I look at it is like this:
Rod bolt nuts are not usually locktited and are normally lubricated on assembly. Can't imagine a more critical nut. The difference is that the torque specified is intended to slightly stretch the bolt. This is the "elastic" portion of the bolt's ability to stretch. Loosening the nut results in the bolt springing back to it's original length. If you go too tight then you're into the "plastic" region and the bolt will not spring back to it's original length. In nearly all cases that over-tightened bolt or stud is then junk.

So if there are no other 'locking' methods, then when lubricated the bolt or stud may just need to be taken into it's elastic region. If there is some other locking method, be it a conical seat like lug nuts or a Nylok nut or a cotter pinned nut etc. then anti-seize would be a good call. Particularly in the rust belt.

 

[Freewheel]

I put moly grease on my OME u-bolts and was not able to get them to spec tightness, and I worry that I might have stretched them a bit when I was trying. The value of 1/2 torque value for threads with dry moly on them is interesting - wish I had known that earlier...

But anyone have any figures for a torque reduction with moly grease??

 

[Spike Strip]

I don't know why I get such a puerile thrill from this thread When it's actually some pretty good tech....

But I can't resist saying: I use Astro-glyde on my lock nuts.

It's a slow night at work... Nobody got Herpes today.

 

[cruiseninak]

Spike I am really curious where you got this info? My experiance with torque critical parts is on airplanes. Torque is always intended to be measured dry no lubricants. Ha ha but seriously. What about contaminants/small changes in the lubricants or on the bolt/stud or nuts that would change their properties?

 

[GLTHFJ60]

Got to thinking about this.

The way that I look at it is like this:
Rod bolt nuts are not usually locktited and are normally lubricated on assembly. Can't imagine a more critical nut. The difference is that the torque specified is intended to slightly stretch the bolt. This is the "elastic" portion of the bolt's ability to stretch. Loosening the nut results in the bolt springing back to it's original length. If you go too tight then you're into the "plastic" region and the bolt will not spring back to it's original length. In nearly all cases that over-tightened bolt or stud is then junk.

So if there are no other 'locking' methods, then when lubricated the bolt or stud may just need to be taken into it's elastic region. If there is some other locking method, be it a conical seat like lug nuts or a Nylok nut or a cotter pinned nut etc. then anti-seize would be a good call. Particularly in the rust belt.

Gotcha. I was thinking that the the threads were the locking method for a bolt with no lock washers or other special seat. That's why I was questioning whether or not using anti-seize was a good idea. If the locking method is the bolt being within that elastic range, as in the factory torque spec, then that is how it locks in place.

Now head bolts have a non-threaded portion which is where I'm assuming it stretches a bit. What a fully threaded bolt that threads into a captured nut or something, all the way to the head?

If anti-seize is such a good thing, then why doesn't the factory use it on all suspension components, or do they?

 

[FJ40Jim]

If anti-seize is such a good thing, then why doesn't the factory use it on all suspension components, or do they?

Because it would cost money and be unnecessary in many parts of the world.

When thinking long term about vehicle service, there are 2 possible risks for the fastener:
1. The fastener can seize in place (rust, galvanic action, thermal weld...), making future service much more difficult.
2. the fastenr could spontaneously fall out because it did not seize in place.

In my part of the world, I use a lot of anti-seez, because it has been empirically determined that #1 is not just a minor risk, but an eventual certainty.

OTOH, #2 just doesn't happen if the right fasteners are installed w/ the right tork load.

YMMV.

 

[ntsqd]

So I pulled out my Torque calc stuff and the results are indeterminate. What compensates for the differences in lubricity is called, and I suspect Spike is going to have fun with this, a "Nut Factor" (K). The problem is that each of the various lubricant options has a range of values. They all overlap and some are quite wide. My printed out reference has been replaced by a calculator.
Bolt Load Calculations/Formulas - Stress, Stretch, Torque, Turn-Of-Nut - Riverhawk Company
Click the "Torque" circle in the upper blue band across the page and you'll see the listing of Nut Factors and their ranges.
If there is interest I can post the formulas necessary to do the calcs by hand.

 

[dgangle]

The conversation of this topic has gone silly. Wer're not working on the space shuttle. We're talking about never-seez on u-bolts and misc suspension component fastners of a +35 year old 4X4.

It never ceases to amaze me how a simple topic can be extrapolted into never-never land.

 

[GLTHFJ60]

The conversation of this topic has gone silly. Wer're not working on the space shuttle. We're talking about never-seez on u-bolts and misc suspension component fastners of a +35 year old 4X4.

It never ceases to amaze me how a simple topic can be extrapolted into never-never land.

I guess, but this is definitely useful information. If we had not taken it to a more detailed level, would you, or more importantly the author of the thread, known to reduce the torque spec when using anti-seize?