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

 

[byrdj]

just consider, if the torque is the same for dry verses well lubricated, the clamping force will be over double. you then need to consider the ductility of the wheel material. I measured yield with only a 20% increase in bolt force for alloy

then in the other vain, if the clamping force is maintained the same, then the required torque would be less than half and would result in reduction of the friction preventing the nuts to loosen.

you could safety wire the lugs to prevent backing off if you want to lube

 

[John2004]

>byrdj wrote:
"just consider, if the torque is the same for dry verses well lubricated, the clamping force will be over double. you then need to consider the ductility of the wheel material. I measured yield with only a 20% increase in bolt force for alloy"

This is worth considering, but we must also consider that if the torque is the same on identical threads, dry and un-lubricated, the clamping force still could probably vary by as much as double. See thread here...

http://www.eng-tips.com/viewthread.cfm?qid=229435&page=1

Of course, when repair shops tighten the lugs down with impact wrenches, they are in many cases going over double the axial loads produced by specified lug torques (I've seen impacts break lug studs right off when tightening).

This would seem to be less of a problem on steel wheels than aluminum, but worth considering in any case.

The thing that puzzles me is, how likely is it that NAPA would state right on their anti seize bottle to "use on lug nuts" unless they did some research and found the practice to be safe ? They also state to tighten all bolts to manufacturers specs after applying the anti seize, making no allowance for a reduction of OEM torque specs.

Safety wire would not seem all that practical. How would it be applied with both open end and closed end acorn style lug nuts ?

John

 

[byrdj]

 

[MintJulep]

I've never seen a manufacturer's torque spec for wheel lug nuts in an owners manual.

I suspect that any torque specs found in service manuals are simply looked up from a "standard" table anyway, and have no consideration of any specific joint design.

I have used anti-seize on all of my personnel vehicles since I have had personnel vehicles. Never had a problem. Never found a loose nut or bolt when removing wheels.

 

[GregLocock]

The repair manual for a car that I have on my desk says 150 Nm for the wheelnut torque.

Cheers

Greg Locock

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

 

[byrdj]

example
1/2 lug gets 90 ft-lbs dry
from my wallet card 1/2, felpro, 40KPSI loading gets 43 ft-lbs
thus felpro and 90 ft-lbs will have you aproaching stud yield

 

[CoryPad]

1. No, using anti-seize will not cause loosening.
2. Yes, using anti-seize can increase joint preload, perhaps beyond the safe limits for the fasteners and/or clamped components.

You are correct regarding liability.

You give NAPA way too much credit regarding the possible effects of their product on bolted joint performance. NAPA is essentially a marketing company and isn't involved in engineering.

You are correct that many places will only tighten lug nuts (or bolts, which are used on many vehicles) with an impact wrench. However, there are many places that do use the torque sticks and a torque wrench.

It is not common practice to retighten wheel fasteners after 50 miles.

The issue of corrosion is an important one. Wheel fasteners in the past used electroplated zinc coatings that did not provide much corrosion protection. This would lead to problems such as those you mentioned. New vehicles use modern multilayer zinc-organic coatings that have much improved corrosion protection in addition to integral lubricant for high preload developed with a "low" torque. Anti-seize compounds vary widely, some won't improve corrosion performance at all, but do reduce the friction. It is important to consider friction in the threads and at the fastener/wheel interface and how that will affect the torque-tension relationship.

American, European, Japanese, and Korean automobile manufacturers perform calculation, analysis, and/or testing for wheel fasteners to develop a proper assembly torque, not just a standard value from a chart.

Regards,

Cory

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

 

[John2004]

Thanks for your replies.

Corypad wrote:
"It is not common practice to retighten wheel fasteners after 50 miles".

When I worked for Goodyear & we sold a set of aluminum rims, we *always* told the customer and noted on the receipt that they were to return after so many miles to re-torque the lugs. This was never done with steel wheels but always aluminum. If you search the net you will see other people mention this as well.

I don't remember the exact mileage they were supposed to return at, I am pretty sure it was between 50 to 100 miles.

Mintjulep wrote:
"I've never seen a manufacturer's torque spec for wheel lug nuts in an owners manual".

The factory service manuals have both recommended lug torque and a recommended tightening sequence. I had always assumed the factory service manuals were based on engineering data produced by the vehicle manufacturer & not standard tables.

Of course lug torque specs vary from vehicle to vehicle, a pickup will have a higher torque rating than a small car.

Nowadays, more and more shops are using torque sticks for lug nuts which is a good thing. A common problem in the vehicle repair industry whether you get your vehicle repaired at a dealer service department or a general repair shop is that many if not most shops use impact wrenches for things that they should be torquing to specs. For them, it's all about getting things done as fast as possible, not about following service manual repair procedures exactly.

Cory, if the anti seize does increase preload significantly, could the lug torque just be backed off by some reasonable percentage to compensate or would this likely cause other problems ?

Regarding the comment about NAPA being mainly a marketing company, that may be true. Permatex makes the anti seize product sold by napa which I mentioned above. My point is that you would think whoever makes and/or sells the product, would make sure that product packaging would not likely get them into trouble liability wise.

If I were making and selling anti seize, and I stated on the product bottle to use the product on lug nuts, prior to making that statement, I would have conducted test after test after test to make sure that it was completely safe to use on lug nuts. Of course you cannot assume that the testing was done, based on product packaging.

I'm glad to hear the newer vehicles have more rust resistant coatings on the studs and lugs. From a safety standpoint, I believe they should either make both the lug nuts & lug studs out of materials that won't rust (for all practical purposes), or coat them so they don't.

John

 

[MikeHalloran]

I got tired of rusted lug nuts decades ago, and have routinely used anti-seize on lug nuts, and on the axle pilot diameters where some wheels take shear loads also.

I use the low end of the recommended torque range with the anti-seize. That's the torque range recommended by the car manufacturer, traditionally specified with new, clean, oiled studs. The anti-seize seems to get you close to the same 'feel' with used parts.

I have had shouting matches with tire dealers about _their_ recommended torques, which are generally way too high for alloy wheels. Yes, I go so far as to bring my own torque wrench to the tire shop, and r/r the wheels from the car myself in their parking lot.

In forty plus years, I have had exactly one lug nut loosen. Not from the anti-seize; from yield of a brain- damaged design of a wheel cover retainer, made of dead soft steel and too little of it.



Mike Halloran
Pembroke Pines, FL, USA

 

[dvd]

I would like to see the car that Mr. Locock has on his desk.

 

[CoryPad]

John,

No automobile manufacturer recommends retightening wheel fasteners after a short distance. Perhaps aftermarket shops do.

Yes, the torque could be reduced for joints prepared with anti-seize.

Factory service manuals contain information derived from engineering data.




Regards,

Cory

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

 

[MintJulep]

Greg and Cory,

So is the wheel-to-hub connection designed taking into account the huge possible variation in preload that is known to occur in the real world?

 

[John2004]

Mike H. Wrote:
"I use the low end of the recommended torque range with the anti-seize. That's the torque range recommended by the car manufacturer, traditionally specified with new, clean, oiled studs. The anti-seize seems to get you close to the same 'feel' with used parts".

That's a good point, it would seem important to know whether the original OEM torque specs are for lubed or non lubed threads. If the OEM specs take into account oiled lug studs, I would not expect significant friction reduction when using anti seize.

Based on my own experience and from what I have gathered so far with my research, it would seem better to use a little anti seize on lug nuts as opposed to not using it. My preference is to use it sparingly, an to try to avoid getting it on the seated contact point between the end of the lug and the rim.

I have also heard of people using a little anti seize at the contact point between the back of the rim and the rotor and/or brake drums. Sometimes corrosion can make rims stick here as well although it's generally not as bad as rusted lug studs. I'm not sure whether anti seize here is a good idea or not.

I have always had good luck with anti seize whenever I have used it. I used to use grease on some threaded connections but found anti seize to be superior.

Just out of curiosity, regarding other applications in general, does the application of grease, oil, anti seize, or lubricants in general on properly tourqued bolted and/or threaded connections, cause any significant contribution to the loosening of the joint ?

Thanks
John

 

[MikeHalloran]

I recall reading a camping trailer manual that recommended retorquing every 50 miles for a while.

The same book also recommended making sure the studs and nuts were _dry_, and tightening until they squeaked... which is a sure way to convert torque into heat, not tension, and ending up with a loose joint, and a fatigued, broken stud. That's just stupid... well, I wouldn't even call it engineering, just a demonstration of ignorance.

On a related note, when I was a kid, the local service station owner did a good business installing seat belts in cars that didn't come with anchors for them... and went to considerable trouble to punch undersized holes through the floor pan for the anchors, drive the bolts through them with a hammer, and use a big wrench to tighten the nuts on the thread- damaged bolts, on the theory that if it was really hard to tighten, it would be resistant to loosening. There's an awful lot of ignorance out there...





Mike Halloran
Pembroke Pines, FL, USA

 

[John2004]

Was it the late sixties Dodge Chargers that used to have left handed lug stud threads on one side of the vehicle and right handed lug studs threads on the other side ? I think it was the drivers side that had the left handed threads.

I think it was an attempt to use the normal forward rotation of the wheels to help to always keep the lug nuts tight. Good or bad idea ?

Perhaps it would mainly only come into play if the wheels were breaking traction and being accelerated and/or spun very fast.

 

[unclesyd]

Things haven't progressed much.

Elton McBroom Chief Engineer Premier Industrial Corp

There is an impressive pile of ignorance atop the subject of nuts and bolts. This article will spade away the ignorance only if it scares the hell out of you --and you stay scared

Taken from "The Whys of Fasteners Failures": Sports Car Magazine; January 1964.

In 1962 Premier had been invited to Indianapolis Motor Speedway to supervise the tightening of all fasteners. After the race for the first time in history there were no broken bolts laying on the track. They stayed for a couple of years until they weren't needed anymore and the next year was the year that there a massive failure of external wrenching cap screws. I recall about twenty cars dropped out in the first 6 laps from connecting rod bolt failures.

Whether the reason for the bolt failure was ever discovered I do know that none of the engine builders were told why. All this time I knew and if I had known that this particular fastener was going to be used I could have prevented the bolt related engine failures.

 

[SincoTC]

Was it the late sixties Dodge Chargers that used to have left handed lug stud threads on one side of the vehicle and right handed lug studs threads on the other side ? I think it was the drivers side that had the left handed threads.

I think it was an attempt to use the normal forward rotation of the wheels to help to always keep the lug nuts tight. Good or bad idea ?...

I think that this would only make a significant difference if the fastener is actually on the axis of rotation and is there to prevent rotation of the clamped part, as on one end of a double ended Grinder or a crankshaft pulley.

Trevor Clarke. (R & D) Scientific Instruments.Somerset. UK

SW2007x64 SP3.0 Pentium P4 3.6Ghz, 4Gb Ram ATI FireGL V7100 Driver: 8.323.0.0
SW2007x32 SP4.0 Pentium P4 3.6Ghz, 2Gb Ram NVIDIA Quadro FX 500 Driver: 6.14.10.7756

 

[CoryPad]

Mint,

Wheel to hub joints are designed to be robust against multiple tightening methods (hand tool vs. power tool) and conditions (lubricated vs. non). However, liberal use of anti-seize on newer parts is not part of it, and definitely could lead to damaged parts.

John,

Using anti-seize on the other interfaces is common in Canada and Alaska where corrosion is extreme. Frequently, those interfaces have uncoated steel parts (hub), so anti-seize can be very helpful. For new fasteners, corrosion really is much reduced and not as much of a factor.

Using lubricants on threads doesn't contribute to loosening.

As Mr. Clark mentioned, using different thread handedness is only useful if the fastener shares the rotation axis with the joint, and only if the applied forces/torques are of the same magnitude as the preload/resisting forces. Central wheel fasteners are used in motorsports and exotic vehicles (Porsche, etc.), so the handedness could be switched. However, the idea of switching the thread instead of increasing preload is not good joint design.

Regards,

Cory

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

 

[diskullman]

Regardless of any other advice about not using anti-sieze, I've spent way too many hours sitting in my driveway with drills & hammers dealing with the results of broken studs, broken lug bolts(used on Saabs) including the smaller alignment screws to hold the disc to the hub. I won't put the lug nuts back on without anti-seize.

Russell Giuliano