Lug Nuts "Turning/Sticking/Turning"
 

A 2009 Z51 coupe, 59k miles today.
Stock painted split-spoke wheels.
Factory lug nuts, lugs and nuts look clean. Never given any oil or anti-seize, but used brake cleaner (no resideue) on them once last year to remove any dust or dirt.
High quality torque wrench, less than a year old and never dropped.

Last winter on a very humid day in the 40's, everything in the garage was literally dripping wet with condensation. I'd had the wheels off and when I was torquing the lug nuts back on (star pattern 40/80/100 lb-ft), at about 85 lb-ft some of the nuts started a move-stick-move action as I was torquing them, like the metal was sticking or galling. I figured this was because of the condensation and didn't worry about it.

Now, 5 months/8k miles later, and after having the wheels on-off twice (tires), I experienced the same thing. About half of the lugs nuts are doing that move-stick-move thing starting around 85 lb-ft, that makes it difficult to get an accurate torque value and makes me wonder what's going on.

EDIT:
Torque values corrected.

Suggestions?

I know you must be doing it in increments because it's a 100ft lb torque. Any one ever run them on with an air gun or remove?
z51vett

Sounds like your studs are about to break off. I know a lot of people are against this, but if used wisely, a little oil will smooth things out and stop any breakage. You may want to reduce your torque a little.

Might have small amount of surface rust in the threads. Might try a new lug and see what it does.

FWIW I have never had that problem with my Gorrilla lugs. GL

Oil or anti-seize may help with the sticking, but it changes the torque setting. If the torque setting is given as dry, don't oil it and torque it, regardless of whether it's a lug nut, head stud, or whatever. Why? Because what's happening when you torque a fastener is you're stretching the bolt/stud. The torque spec, while measuring rotational torque, is really to ensure you stretch the fastener the right amount. If you use oil or any lubricant on something with a dry torque spec, you'll stretch the fastener more when you torque to the same spec. Bad idea. Trying to guess at how much to reduce the torque spec to stretch the fastener the same amount is a worse idea. There's no way to use any kind of lubricant "wisely" on a fastener with a dry torque spec.

I don't think the sticking the OP describes is because the studs are "about to break off," I think it's because there's some small amount of galling in the threads, either on the studs or inside the lug nuts.

OP, is this happening on all studs, or just some? If just some, inspect those closely, both the stud and the threads in the lug nuts for any dirt, debris, galling, etc.

Try a wire brush? I have a wire brush that mounts in an electric drill. I'd run that rascal on all the lug nuts in case there's rust in the grooves. I'd also use a battery brush on the inside of the lugs if they were showing dark threads. Sounds like some rust is forming and needs to be polished out of there.

Elmer

Clean STUDS with WD-40 and wipe off completely. Do not spray
WD -40 into lugs nuts. :flag::cool:

Were your wheels still in the air or did you have weight on them ?

:iagree:

We had a guy who posted last year about using some WD40 on his lugs and promptly snapped off two of them before ever getting to 100 lb-ft.

Unless your torque specs list some kind of thread lubricant, using it is an invitation to serious over-torquing. If you're going to do something that out-of-spec, why bother to use a torque wrench at all? Just use a long cheater bar and jump on it a few times.

Some people use thread lubes and have no problems.
My mother smoked two packs a day for most of her adult life and never had a problem.
I don't smoke and I don't use thread lubes, unless specified in the torque value.

I always hand-torque. I tell the dealership and tire shop to do the same, I think they do because I re-check after getting home and usually get just a very slight movement on a couple.

Wheels were in the air. Rears wouldn't move because of the trans/parking brake, fronts I use a wood wedge to keep them from spinning.

I'll try the wire brush trick and see if that helps. I also have a spare set of almost-new factory nuts, was hoping to save them but maybe this is the time to use 'em rather than just cleaning the originals.

I use anti-sieze on all the lugnuts on my vehicles. Been doing it over 25 years never had a problem.

Some people smoke their entire life and never get lung cancer. Doesn't mean either one is a good idea.

From one source on this topic: Arbitrarily changing the torque value 15%-25% by adding lubricant when it's not supposed to be there (or vice versa) is a bad idea, no matter how many times you've gotten away with it in the past.

:thumbs:

After 30+ years of dealing with galled threads and broken screws in my machine shop, I've come to the conclusion a dry thread is an unhappy thread. And also, it's almost impossible to relate this experience to others.

is it possible they are slightly ouf of round due to overtorquing by someone?

is it possible they are galling on the wheel? check for signs of unevenness on the face.

I couldn't agree more, machinist myself over 30 years. I've machine screw threads from triple lead acme to buttress to whitworth,pipe threads,metric even square threads.

You and the OP are the only one making any sense. :thumbs:

The two guys that claimed to have 30+ years in the trade are giving machinist a bad name.

Back in my past life of "Keeping Ships Fit To Fight", changing "dry install" to "lube install" fasteners will literally take an act of congress along with exhaustive testing prior approval for use. It was not a subject taken lightly due to the facts already covered by Steve_R.

That said, OP, after detail wire brushed, degreased, cleaned and blown dry, you need to take a real close look at the mating hardwares for abnormality. After verified having normal fit and finish, try by hand, switching known good lug nut on suspected stud and vice versa to form a base line. Do not use Gorilla brand, it is made in Taiwan with a poor reputation. On the other hand McGard is a better product with lifetime warranty, if going for aftermarket.

Most importantly, have your torque wrench check and calibration verified. Some SnapOn trucks have rechecking tool. Personally, I only use calibrated SnapOn or CDI torque wrench. SnapOn was used exclusively in Nuclear Power works for a good reason.

GL

:flag:

I agree. The automotive industry typically uses a "Factor of Safety" of 3. The airline industry uses 1.2 to 3 depending on the part.

So automotive wheel fasteners have something like a 300% safety factor built in and probably more because of the critical nature of keeping the wheels on. Meaning a 100 ft-lb fastener can take 300 ft-lbs before the load approaches the fasteners actual strength. A 10 to 20% over torque means nothing to a wheel lug or nut. Put anti-seize on it. Your threads will like it. And your threads will last longer than you.

http://en.wikipedia.org/wiki/Safety_factor

I would clean the studs and try a new set of lug nuts. There could be some deformation to the conical section of some of the nuts. Also, if the lug nuts were every over torqued (due to lubricant or whatever), the aluminum alloy wheel section that carries the clamping load of the lug nut could be galled, or deformed.

Question: if you leave the wheel off, and screw on the lug nut(s) by hand does the nut go nearly all the way down just by hand? If not, something is wrong with the stud or the nut.

Since GM wheels are hub centric, the hub shoulder carries the verticle load, not the wheel studs. So torquing the lug nuts on the ground or off the ground, should not make a difference as long as the wheel is flush with the hub bearing flange.