Lubricating the wheel lugs is a discussion that pop up now and then. This is some background and insights:
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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.
__________________
Wally Plumley
----
"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."
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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.
RKD
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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.
Dave C
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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
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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.
__________________
Wally Plumley
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Are the calottes (rounded surface that contacts the wheel) lubed? That was the
point of this whole thread.
__________________
Wally Plumley
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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 Ball
----
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.
BerNard94
----
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 :)