G-MASSA

I think my engineering degree is wearing off ... I was incorrect in my belief that the torque to overcome fastener elongation (clamping force) was the main component of the overall torque load. The thread and seat friction components are by far the main components of the overall torque load and thus clamp loads are greatly affected by lubrication in typical applications. Torque to load is seldom used alone in critical automotive manufacturing settings because there is more error / risk that the design load ranges are not achieved. It's a very complex science. After all the calcs are verified a simple torque to dry load is applied because that's the easiest way to handle the least amount of variables (and no consumer has the tools to do what the factory does).

In short- I wouldn't under torque.

Overthinking? Absolutely! But that's also how our fine cars came to be!

pp000830

Hi Jason,
I looked in the 993 Shop Manual and the specification book. Nowhere does it specify lube when mounting aluminum wheel nuts. Where did you read this?
Andy

JasonAndreas

The Workshop manuals and TSBs are cumulative, so you really need EVERYTHING published beforehand (there are also Porsche dealer mechanic's training manuals for the 993 that were separate to the workshop manuals that go into more detail). And if you look at the yellow pages at the very beginning of your 993 workshop manuals you'll see "Survey of Information Published in Technical Manual beginning in 1985". In there you'll find the reference to the original TSB,

"Aluminum Wheel Nuts" 5/85 - Special Tool P 300 - 07.06.85

Which unfortunately I do not have an electronic copy of (PCNA use to sell a book (part numbers #PNA.000.082. A-Z, the first collection of 993 specific TSBs is #PNA.000.082.E) containing every TSB for that year for every model, they still occasionally pop up on ebay) but what I can send you is a screenshot of another early TSB with the exact same info.

Quadcammer

this has literally gotten to new levels of anality.

1. In four years of ownership of this car, I have never once ever placed any lubricating liquid on the lugnuts. Miraculously, the lug nuts A) have not fallen off; b) have not become so fused to the studs that they cannot be removed.

Literally across the world people put lugnuts on with just a hand wrench, no torque wrench, no special optimoly bull****, no socket wrench made of ginger root, and yet wheels falling off is not a common occurrence.

The fact this is even being discussed in such detail is just mind blowing.

JasonAndreas

You should see the Audi A8s equivalent of workshop manuals. Talk about covering your *** or in this case, the corrosion warranties, when it comes to mixing aluminum and steel fasteners, what needs lube, what doesn't, etc. The Audi A8 approved collision/body centers are required to use different tools for each metal...

One of my favorite Porsche TSBs for the 993 is 64-9403 Mixing of Windshield Cement.

which means there were dealer mechanic(s) somewhere that didn't realize they were supposed to mix a two part adhesive (and yes the tubes were clearly marked part A/part B) for it to work. Common sense to some, not so common to others.

d ward

Whilst we're all debating if to grease our nuts or not

It maybe useful to know if there is an equivalent to this optimoly grease with its no doubt large helping of Porsche tax

Is it just an Aluminium anti seize grease or is it something else more specialized ?

Matt Lane

A small tube of the Opti-Moly would probably last 2 lifetimes if used sparingly as intended. I'd suggest "Why bother?"

Just a thought.

Oh, and lotion for one's nuts is always nice.

Best,

Matt

d ward

hi matt
I can see your point, but a tube of it is around $70
So if the same thing is available for a few $ without the Porsche badge
I
Would prefer to spend the money saved on something else for the Porsche as I'm sure some other owners probably would

I know lots of people think anything from Porsche parts department is lovingly made by unicorns and handmaidens from unobtaniam and so won't buy from anywhere else ;-)

But as a lot of Porsce stuff is just someone else's stuff repackaged, I'd rather buy that at a fraction of the cost where possible

:-)

Matt Lane

I'd have to agree! I seem to remember paying less than half that - but I am well along into my lifetime-supply tube!

Cheers

Matt

JasonAndreas

The North American MSRP is $38.55USD and it can be found for less than $20 at dealers (try Sunset Imports). Which isn't that much more than a lipstick balm of loctite. And once you start taking the rest of the car apart you'll find that its called out for all over the place.

Here's the Specifications and MSDS.

The only thing that stands out with the Castrol paste lubricants is that they don't affect torque specifications (according to Porsche). Every other brand always warns of the exact opposite.

Paolo1

Since the threads and the shoulders of the nuts require the optimoly, what part of the nut is the 'shoulder'?

Is putting optimoly on the threads of the bolt equivalent to trying to reach inside to put some on the threads of the nuts? I am sure the reason is likely clear to everyone here but me.

Thank you for indulging me.

Edward

You said it: warranties. In other words, litigation. Bottom line: CYA because some numbnut is going to go for deep pockets despite his obvious mental inadequacies. Yup, our world today ...ugh.

That said, it is prudent to use antiseize with some fasteners. But the key is where to apply it, and how much; or in some cases you must not. This is where the manual and prudence intersect. With lugnuts, clearly the world has gotten away without applying factory torque values and lube, but the world is also replete with steel wheels/bolts mounted to trucks, econoboxes, and beaters. This is a low bar, and one I'd not aspire to when discussing any genuinely nice car. So yes, abide by the stated torque values as the factory has likely gone through just a bit more R&D than any poster here. And for lugnuts, I use a very small amount on the mating surface of the lugnut/wheel, and even less still on the threads. And I do this on every single car we have had, the extended family has had (because I had been everyone's designated wrench), and this for decades, and all for the simplest reason: I had to use a hammer, socket (which got destroyed in the process), and mondo breaker bar to deal with a Ford's lugnuts once many eons ago, and I swore never again ...at least with any car that I work on! Good judgment is one thing, overthinking wholly another. You decide.

Edward