Anti Seize? - PeachParts Mercedes-Benz Forum

Gil · #1 10-28-2002, 12:03 AM

Has anyone ever used anti seize compound on their wheel studs?

I've got a 300CD with lug nuts that are a real pain in the ass to remove, and I'm considering using some of that silver anti seize compound to make the job easier in the event of a flat tire.

Problem is, I don't want to have the lugs come off on the highway or any other time, for that matter.

Any ideas or thoughts on this subject?

Gil

1984 300CD

#2 10-28-2002, 11:36 AM

or Thread-locker a much better choice, since it is just about as effective as antiseize in preventing the bolts from rusting in and helps to keep them tight in its own way. And for heaven's sake, use a torque wrench anytime you're not in an on-road emergency situation to avoid warping the rotors or hubs by uneven tightening! T-bars can do just as much damage as air wrenches.

Gil · #3 10-28-2002, 10:47 PM

I always criss cross the bolts when tightening them, no matter what car I'm working on. It's just good policy. A special set of Mercedes-approved, anal-retentive instructions on how to do this for my particular auto seems a little over the top, but I'll give it a look

I will go ahead and try some anti sieze the next time, though. Thanks to everyone.

Gil

Luke@tirerack · #4 10-30-2002, 08:12 AM

as previously posted ... remember the SEARCH function is your friend

Anti-sieze on a lug bolt is a very bad idea !!!

Here's why: Bolts or studs provide clamping force by being purposely stretched. Most torque specs bring a bolt well within its elastic limit. Then when loosened they will return to their original length and can be safely reused (Some bolts, including many head bolts, are purposely stretched past their elastic limit, and can not be reused). The torque wrench is the most convenient-but not the most accurate-method of properly stretching
automotive bolts. Engineers spend hours correlating the proper bolt stretch to the required turning effort.

About 90% of a torque specification is used to overcome friction; only 10% of the specified twisting effort provides clamping force. It is no surprise then that most lubricant tables recommend a 40-45% reduction of applied torque when using
anti-sieze on a bolt. So, a lugbolt coated with anti-sieze should be tightened to a maximum of 49 ft-lbs. Tightening this lugnut to 85 ft-lbs. means it is now over-torqued by 73%! Considering that most torque specs stretch a bolt to within 70% of its elastic limit, over-torquing by 73% will easily send the bolt or stud well beyond its elastic limit-and could be dangerously close to its failure point.

For this reason I would suggest to all forum members to never use anti-seize on your lug hardware.

Gil · #5 10-31-2002, 12:00 AM

Well, THAT wasn't something I'd considered at all.

So, what your saying is that if I use anti sieze and tighten the bolt as I normally would, I'm actually going to get that bolt tighter than I would have (because of the lubracitive rpoerties of the anti sieze product), and put the steel at a greater risk of tensile failure?

I'm a little surprised that this could happen by simple hand tightening, as the addition of a simple 'lubricant' would result in maybe an additional quarter of a turn placed on the lug. Remember, I'm trying everything I can to prevent these lug bolts from sticking. Why would the addition of a dab of anti sieze suddenly endow me with superhuman stregnth to put the lug bolts in a perishable position?

Moreover, isn't there a wide margin of error designed into something as critical as a lug bolt (they really are bolts on this car, not nuts)?

All I'm trying to prevent is getting stuck on the side of the road with a frozen lug bolt and a flat tire.

Am I totally off track in suggesting the anti sieze danger is overstated?

In any case, these lug bolts are stubborn beyond any I've ever dealt with before. I'm still thinking of using the anti sieze, but also making sure I don't tighten as I normally would, but rather less than normal.

Do you think this approach would be safe?

Gil

Luke@tirerack · #6 10-31-2002, 07:51 AM

just make sure that the threads of both the lug bolt and lug opening in the hub are clean, dry and in good condition (no burrs) and you will not have a problem. It is very easy to over tighten lugs by hand if you are installing them incorrectly. As stated before anti-sieze on lug harware is an extremely BAD IDEA. By the way, all Mercedes vehicles have lug bolts not nuts.

oldsouth · #7 10-31-2002, 08:43 PM

Luke is right, any lubricant on threads will allow you to tighten more than dry. I used to have a whole tree chipper that the knives would get loose and the manufactor told us to spray wd-40 on the threads before tightning with the impact. That did the trick.

Jim Anderson · #8 11-01-2002, 11:13 AM

Why does Mercedes use bolts instead of nuts? Peugeot uses nuts, you mount the wheel on studs and I miss them a lot. Wheel mounting time is a tenth of the time that way

oldsouth · #9 11-01-2002, 11:59 AM

I have wondered that myself. That and canister oil filters.

Gil · #10 11-01-2002, 05:36 PM

I can't remember the exact engineering/physics behind it, but for some reason, wheel bolts do, in fact, hold better than wheel nuts. Proabably something related to more surface area (threads) coming into contact with each other than in most wheel nut arrangements. Take a look at how long the wheel bolts are versus your average lug nut. Thinner nut equals fewer threads resulting in less (friction based) tensile stregnth. Safety was likely the reason MB went this way.

VW used to do this also, but switched over after everyone complained. Race cars rarely use wheel bolts either, so I'm skeptical as to any appriecable safety advantage versus saved time and less cursing aloud during a tire change.

My two cents.

Gil