Use of Anti Seize on vehicle lug nuts 6

[John2004]

Hi everyone,

I would like to start a discussion on the use of anti seize on vehicle lug nuts. Searching the net, there are people that claim to have used anti seize on lug nuts for many years with no problems, and some people that advise against it.

I have two main questions I would like to address separately. The two questions directly below are related to the two main sources of controversy on the subject.

1. Will the use of anti seize on properly torqued vehicle lug nuts likely cause them to loosen over time, to the point where it could be dangerous ?

2. Will the use of anti seize on vehicle lug nuts cause a significant increase in the axial loads and/or stresses on the lug studs, that would likely cause a significant problem or danger ? If so, I would think you could simply reduce the specified torque by a certain percentage to compensate for the use of the anti seize.

I have a bottle of NAPA anti seize (item # 765-1674) and interestingly enough, it says right on the bottle to use anti seize on lug nuts.

I would expect most engineers and auto manufacturers to recommend not to use anti seize on lug nuts, even if they're not sure either way whether or not it would cause any problems, just because of safety liability.

On the other hand, one would think that a large company like NAPA also considered safety liability, and would not state right on the product bottle to use anti seize on lug nuts, unless it was a safe practice.

On the bottle of the NAPA anti seize product mentioned above, under directions, it states to apply the product, and then torque all bolts to manufacturers specifications.
The directions make no torque reduction allowance for the lubrication effects of the anti seize, and the effects it may have on increasing axial loads beyond those anticipated at OEM specified torques.

Also on the NAPA anti seize bottle, it recommends the use of the product on engine head bolts, but again, does not provide any recommendation for an OEM torque spec reduction with the use of the anti seize, which leads one to believe that it may not be a significant issue.

Most repair shops are not going to torque your wheels anyway, they will use impact wrenches which always over torque and many times warp rotors. Some shops use torque sticks on the end of the impact wrenches which is a good idea, but you would be hard pressed to find any shop using torque wrenches on lug nuts. It's just not fast enough for them. Even if you request that they use a torque wrench, they may likely forget, so you would have to watch them. I know because years ago I worked in an auto repair shop.

I have used anti seize on the lug nuts of one vehicle I have and I have not had any problems. I used it very sparingly, and I tried my best to make sure that there was no anti seize between the end of the lug nut (part that seats in the rim) and the rim. These were aluminum rims with closed end acorn style lug nuts. I re torqued after driving 50 miles or so which is standard practice on aluminum rims anyway.

The reason I used the anti seize is because I had to remove a tire once and the lugs were so rusted I could not remove the nuts without a breaker bar. I thought they might break. After that, I removed the lugs on all the wheels, replaced them with new lug nuts, and applied a small amount of anti seize to each lug stud at the time of replacement. That was years ago and I have not had any problems.

Many times cars will come into a repair shop with rusted lugs. Some lugs will come off with an impact wrench and others will break off because they are too rusted. However, just because the lug nut came off with an impact does not mean that the stud was not damaged, fractured, or over stressed when removing the lug nut, due to the corrosion present. This is another reason I can think of to apply something to lug nuts and studs to keep them from rusting.

Is there anyone out there that has had some real world experience with this, perhaps with fleet vehicles ?

I would appreciate any feedback or thoughts.

Thanks
John

 

[unclesyd]

You can go to RS Technologies and get a little more information about applied torque and tension on a fastener. They evidently do a lot of work with lug nuts. The first link is to there fastener testing methods.
The second link is to the download page with several good papers on fasteners. The first paper has a good picture of how the applied torque is used by the fastener. Two can be downloaded and the others have to requested.

http://www.rstechltd.com/fastener_testing.html

http://www.rstechltd.com/Technical_articles.htm

 

[tbuelna]

The stock steel wheel studs on my '02 Chevy 1/2 ton truck have what appears to be an aluminum coating/plating. I'm guessing its purpose is to prevent galling or seizing. The owner's manual specifically says NOT to put any type of lubricant on the wheel studs or lug nuts.

For the record, the OEM wheels are cast aluminum. The lug nuts are some steel alloy with zinc plating. And the lug nuts have never come loose in 90K miles of driving.

 

[CoryPad]

The stud coating is a multilayer product either from Metal Coatings International or Magni.

http://geomet.net/coatings.htm

http://www.themagnigroup.com/500series.html

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[limey1]

Ref: John 2004.
I have seen commercial vehicles in England fitted with left and right hand threads. The easiest way to remember the handing is they always tighten toward the front. Ive seen this as far back as the old British Leyland double decker buses. Now granted, these nuts are tightened with an 8' bar and Dolly (With anti seize). As far as persoanal vehilcles, as long as you use a strong arm or decent wheel brace (As opposed to an air wrench) to tighten these nuts, there is no problem using anti-seize.

 

[LGR]

I was always convinced it was the taper on the lug nut that when wedged into the wheel with torque kept the lug nuts from coming loose, not the thread. The thread was there to create the force required.
The left hand thread would only be of benefit for wheels such as the "knock Offs" (one big nut in the middle) on the wire wheels of old Jags. This was stated technically correct earlier I just thought I would give an example.

I've been told that anaerobic thread lock liquids act as a lubricant when in a liquid state, any comment on that? I wouldn't recommend it on wheel studs though, not because it would cause any damage it just isn't necessary.

Yes, I have used anti-seize on wheel studs for 30 years.

 

[ScottyUK]

I seem to remember in the mid-80's reading about some research into the reasons why a lot of British trucks were losing wheels around that then. I was a teenager at the time, but this thread stirred a memory. While looking for a bit more information I found this report from the UK's Transport Research Laboratory might be of interest:

http://www.dft.gov.uk/pgr/roads/veh...eldetachment/heavyvehiclewheeldetachmentr1727

One thing we see on many British trucks these days is a series of indicators which clip on to the wheel nuts and which make any loosening immediately apparent. E.g

http://www.tyre-rite.co.uk/detail.aspx?ID=1402.

Are these common in other countries?


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If we learn from our mistakes I'm getting a great education!

 

[strWennie1]

I think my advisor at the University worked with someone on a MS thesis on the topic. From memory.

First, lug bolts are way over designed for the loads- due to shop, abuse, liability.
2) I think OE's official stance is lug bolts/nuts are to be replaced not reused- then the coating is intact. Torqued dry clean threads.

I personally use a little on the threads. All my cars have bolts or nuts where the head has a conical to seat the wheel. This is where big time friction holds things. I keep it off the seat- just the threads. Replace studs and or nuts when they no-longer thread easily by hand inidcating they have yielded or been cross-threaded.

I would imagine all these combo's are steels with a long elongation. That way they yield and don't break, rust slower, and don't have stress corrosion issues like some higher strengths. They are probably cheaper too.

M

 

[mkkessel]

IMO, the use of anti seize prevents galling and lubricates the threads. Lubrication using anti-seize may well give only a slight frictional advantage over clean dry rust free hardware, but that advantage opens up widely on used, galled, rusted, or corroded materials. Although torque is no indicator of pre-load, the more friction-free the process of tightening or tensioning is, the greater the chance of achieving a satisfactory pre-load will be.

The use of torque wrenches at tire shops only came into vogue after aluminum wheels became stock equipment on many cars and trucks. Sorry to say, but the torque wrenches aren't for the purpose of accurately pre-loading the lugs. Instead they offer the tire dealer a hedge against fracturing cast aluminum wheels.

Even if lubricated, the larger variable in terms of friction is the tapered shoulder on the lug. This taper design is essentially used to more easily center the wheel on the stud as the lugs get passed over when step tightening. Unfortunately this design also adds a significant surface area resulting in friction read at the torque wrench but not applied as suitable stress.

"Tighten until the stud snaps, then back off half a turn."