Lubricating the wheel lugs is a discussion that pop up now and then. This is some background and insights:
Optimol TA datasheet.pdf
From the 1986 booklet of service info by year:
Wheel Nut Treatment on Aluminum Rims
If wheel nuts are lubricated with the wrong type of grease prior to installation or even installed
dry, the spherical calottes of wheel nuts could seize in the countersunk holes of the rims.
The factory is using OPTIMOLY TA paste successfully at the present time.
This lubricant is available in 150gram tubes for Service (Part No. 000.043.020.00).
The tightening torque for wheel nuts is still 130 Nm.
Lots of interesting reading in this series of booklets, available in Jim Morehouse's CD set.
"Optimol, a German Company, was taken over by Castrol many many years ago. Optimoly TA is now
called Optipaste TA and is available in 400 g spray cans, and 500 g or 5 kg containers from Castrol
distribution outlets. Another very similar product is Mobil’s Greaserex RGM-2. [Doug Hillary —
Australian landshark mailing list.] Both Porsche and BMW specified Optimoly TA for wheel nuts on wide variety of models.
Never use a copper based grease such as ‘‘coppercoat’’. The copper reacts with water and bonds the aluminium nut to the steel studs."
When I first started driving Porsches over 10 years ago the local Porsche shop told me to always use a little daub of anti-seize on the threads before replacing lugs. Told of the numerous times their custom made hole saw/lug removal tool was necessary to get wheels off.
Don't forget to point the crest on the center cap at the valve stem.
I remember reading the WSM page a decade ago. I dimly recall doing some googling (search engine of the day was Alta Vista back then) and determining that the Optimally TA was more-or-less aluminum-based anti-seize paste and the CU was copper-based anti-seize.
We didn't quite try everything. The Dremel with the snake attachment was MIA. I've successfully removed the lug collet with a Dremel and various of the cutting tips. It's a real PITA, but you can do it with less damage to the wheel than with a hole saw. It certainly isn't as quick as a hole saw though.
But, in the case you reference, the primary issue was someone (other than you or me) using an air impact wrench with a cracked socket. The cracked socket only applied force to the top of the lug nut. This if course just banged the hex part of the nut off of the collet. The socket in question was a 'normal' socket and not an impact socket. So, it's also possible that the socket cracked while the air tool was being used the first time. I don't think lube/anti-seize of any sort would have helped in that case.
That particular incident was the final nail in the air-tool coffin for the magnesium OEM nuts as far as I was concerned. Prior I'd never used air tools on those nuts. But at this point I tell folks around here never, ever to use air tools on those and relate our little nut experience to reinforce. Never use air tools on those. They don't like them at all. Since then I've had to replace nuts or chase wheel stud threads on other people's 928s on which air tools had likely been used prior.
There are many that will argue the issue of using graphite products on the aluminum. IIRC, the Porsche recommendation is for applying a thin coating to the cone face of the nut, but they do not recommend adding any to the threads. Adding any oil or friction reducer to the threads changes the pressure applied to the face at a given wheel nut torque, so there would be a threat to inadvertently over-pressure the metal face junction.
I've been using a thin coating of waterproof non-graphite grease (Redline CV-2) for years now with good results. My use pattern may not be typical, since the wheels are off regularly for cleaning and inspection. The only water that the wheels and suspension parts see is when washing the car. There is no salt used on our sunny warm-weather-only roads, so electrolysis in not an issue. Add in religious use of the torque wrench too.
For those who follow the red-stud philosophy, a reminder that the red stud is an indicator of how the wheel and tire combo was installed at the factory, useful for diagnostics only when the original wheel and tire is installed. Many of us have replaced the wheels, all but one or two museum cars have had tires replaced. That said, I still follow the habit. Unless you are doing on-car balancing of the whole rotating assemblies and need to reinstall the wheels/tires back in their as-balanced relative positions, the practice is of no real value.
Dr Bob, '89 S4 Auto, black
dr bob said, "There are many that will argue the issue of using graphite products on the aluminum."
Actually I am one of those. Back when I was building airplanes for a living, we had strict rules about even using a standard pencil for layout marks on aluminum parts - graphite corrodes aluminum.
It might not be a problem when the graphite is encapsulated in the anti-seize grease, but it still makes me nervous.
Are the calottes (rounded surface that contacts the wheel) lubed? That was the point of this whole thread.
FYI, throughout this message thread, Optimoly TA was mentioned as the factory lug nut lubricant. I couldn't find anything in the WSM about that. This bulletin says Optimoly HT, which is copper-based, applied to the shoulder as well as the threads for aluminum lug nuts. I couldn't find anything later that superseded this bulletin.
bill (et al), bulletin 4-8507 was replaced by 4-8607, and then replaced by 4-8613, finally replaced by 4-8813. (clear as mud now).
tsb 4-8813 (current as of 2005), covers ALL Porsche models with aluminum wheel nuts, states to use optimoly TA.
WARNING: DO NOT
USE OIL, GREASE, ANTI-SEIZE OR LUBRICANTS ON LUG NUTS WHEN CHANGING TIRES
Proper torque on lug nuts is very important for three reasons. One is to keep the lug nuts from loosening up and the wheel coming loose, another is to prevent distortion of the brake rotor behind the wheel, and a third is to prevent broken studs. A torque wrench should be used for final tightening of the lug nuts, and the nuts should always be torqued to the recommended specifications.
CAUTION: Torque specifications for lug nuts are always for CLEAN and DRY studs and lug nuts. That means no oil, no grease, no anti-seize and no lubricants of any kind. Any of these products will reduce the friction between the threads. This may seem like a good thing to prevent rust and frozen lug nuts, but the reduction in friction means a much higher percentage of the applied torque (up to 25% or more) will go toward loading the lug nuts. The end result may be brake rotor distortion or broken studs!
Wheel studs should be cleaned with a wire brush to remove rust and dirt BEFORE the wheels are mounted. If the lug nuts are heavily rusted or have damaged threads and won't turn easily on the studs, replace the lug nuts. The same goes for any wheel studs with damaged or badly corroded threads. And remember to mount the wheels DRY with nothing on the threads.
C O N F U S E D ?????? So am I :)