Wheel nuts

[graham.webb]

A simple desire to get my wheels refurbed has produced a saga of a fruitless journey and jammed wheel nuts. The two offending nuts have now been removed by my indie (terrifying use of a 19mm hole saw), and my car currently sits on a set of borrowed wheels. So grateful that they've sorted it out for me.

Here's the question, though...it seems that what with electrolytic corrosion and overtightening the idea of aluminium wheel nuts is doomed to problems (apparently it's not uncommon for them to shear off at the collar), so what's the argument against using steel nuts??

Racers use them, and everyone sells them (even if they're listed after the chrome nut covers and locking jobs), so would I be better off buying a steel set to reduce the risk??

Looking on the bright side, I reckon the locking wheel nuts are rendered unnecessary by all this!!

 

[Copperman05]

Personnally I dont think there is an issue with using new alloy nuts. Its not surprising that after 20+ odd years some will start to corrode and cause problems similar to those you have encountered. Changing the nuts every 10-15 years wold probably negate the issue. Where are you thinking of getting your wheels refurbed? I had my done at Lepsons and although not cheap the finish was like new. Edd

 

[Alpine]

at £2 to £4 per nut, it is not worth the worry, just get a new full set of alloy ones. They'll last at least 5 years. I got mine from Berlyn Services, see here: http://www.partsforporsche.co.uk/

 

[Mike_Pollock]

Put them on with a smear of "Copperslip" and they will be fine. Id also smear it on the mating surfaces wheel to hub/brakedisc/spacer, as electrolytic corrosion can occur here too.

 

[Pastry]

bit of a debate on ph about copper grease i was reading today; http://www.pistonheads.co.uk/gassing/topic.asp?h=0&t=969689 a few say not to put copper grease on alloy nuts as it can accelerate corrosion? don't know if theres any truth in it, i used it on the bolts for the spoiler and hatch pins as one was seized when i took it off. they undid fine when i got round to replacing the pins about 6 months later.

 

[bmnelsc]

In Canada builders were using aluminum for house wiring during the 70's which lead to corrosion problems when connecting to normal copper based fixtures, receptacles, switches, etc. To combat the problem, the use of an anti-oxidant paste was made a requirement for all connections between copper and aluminum components. I would think using copper based grease on aluminum components would aid corrosion rather than inhibit it. Because it is grease it would block contact with air which may offset the natural tendency for dissimilar metals to corrode when in contact. I'd think an anti-oxidant paste (usually contain zinc) would be preferrable to copper based grease for this purpose.

 

[geoffbateman]

I would not recommend a copper based grease for aluminium to steel jointing as the conductivity of the grease can actually aid corrosion which is an electrolytic process. I use a good grade PTFE type grease which seems to work well. I also remove the wheels a couple of times a year (to clean) and regrease the nuts at the same time. Obviously ensure that the nuts are torqued up correctly 94lb-ft, I believe and if anyone else has had the wheels off I always, at the earliest opportunity, undo the nuts and re-torque them to the correct setting, that way I know they are right.

 

[Hilux]

I have been using copper grease for 20 years without any issues at all My Landcruiser with alloy wheels has had coppergreased nuts and hub/wheel interfaces for the last 6 years My 944 had the same for 3 years My Mk1 Golf has them now Cars I`ve rebuilt with alloy engine parts are all coppergreased if they dont need thread lock Its also supposed to destroy rubber on brake pistons etc if it gets on them (it doesnt) Eggs were once bad for us - now they are not Meat was bad for us - now its not I can guarantee that if copper grease was so bad we would have known about it years ago. Re wheel nuts - use moly grease if you`re scared

 

[sawood12]

Copper grease if perfectly fine and perfecto for all the jobs mentioned here - the problem is that people use too much of it. You only need to use a small smear. And copper grease inhibits corrosion - it doesn't conduct electricity and therefore insulates mating surfaces and inhibits electrolytic corrosion.

 

[Alexw]

Maybe its alu + steel + salt + copper that does the damage? I'd have thought the grease would stop the corrosion as they grease doesn't conduct? Even with the copper in it. I've used copper grease and just normal grease on mine so far and no problems... other than when I accidentally lean on the exposed threads and get covered in the stuff [] Infact the only time I had a problem was when I cleaned the grease off the face of the hub as I was working on something there and forgot to reapply, it took a lot more force to the next time I took the wheel off. I'd have thought the ones that are corroding are the ones that are dry. The only problem I've heard with alu bolts, that actualy happens, is idiots with rattle guns rounding them off. They should be torqed up properly by a soft socket - 130nm IIRC? Infact the threads should be greased because its a wet setting, putting them on dry means they might not get tighted up to the wheel properly. This happened to someone on here a few years a go on a track didn't it? I've heard problems with people buying locking nuts as it unbalances the wheels.

 

[pauljmcnulty]

Meat was bad for us - now its not

Blimey, you're so behind the times! Didn't you year Friday's news, meat is now bad for us again. I recommend you read the Daily Mail, that'll keep you up to date. [][][]

 

[Hilux]

The great thing about copper grease is that if the solvent dries or burns off it leaves a copper deposit that prevents electrolytic action between dissimilar metals. You are correct - dont use too much.

 

[graham.webb]

You're probably right Alex. I know from my work on building systems that even two dissimilar, but supposedly passive materials will set up a "cell" and corrode in the right conditions. Stainless steel and galvanising (zinc) to be precise. I think the official Porsche recommendation is Optimoly aluminium grease...available in a tube from OPCs. On the basis of what you've said, I expect even plain grease would be better than nothing, especially if the torque figure is "wet". Still think the idea of aluminium nuts is flawed in that it's not idiot proof. The effect on rotational vibration must be minimal too, as the nuts are close to the centre, and anyway the addition of a great clunky locking wheel nut spoils it surely? Thanks for the comments....I'm still wondering if many people have cried enough and pelaced the lot with steel nuts?!

 

[sawood12]

I really don't think there is a problem with alloy nuts, they just need a bit of consideration - like using a decent well fitting 6-point socket instead of a 12-point one to ensure you spread the load over a larger area when undoing and tightening up the nuts - also best to observe the correct torque when tightening to ensure you don't over-tighten. Also it is probably a good idea to have a tin of satin black paint and give them a spray every couple of years or so. The biggest risk with them is when you take it to have tyres installed and you get some ham-fisted mechanic with an air tool over tightening them and bashing them about. I personally don't like the look of chromed nuts and sometimes the chrome plating can become cracked and flake off, so though more robust, the steel nuts are completely immune to abuse. I've wondered if you could remove the studs altogether and use a bolt from a more modern car instead of nuts.

 

[Hilux]

Still think the idea of aluminium nuts is flawed in that it's not idiot proof. The effect on rotational vibration must be minimal too, as the nuts are close to the centre, and anyway the addition of a great clunky locking wheel nut spoils it surely?

Look up unsprung weight and gyroscopic force. Less weight etc better turn in and losing unsprung weight is 10 x better than losing sprung.

 

[graham.webb]

Thanks Paul...I'd forgotten about that!

 

[chrisg]

I've had 2 x 944's both with alloy wheel nuts, total ownership > 10yrs - never had a problem with them. With regard to copper slip, I must confess I liberally spread it over any 'exposed' thread that could potentially get rusted up or bind, that way any parts of the car are easy to remove. I have a the express recommendation of my 'engine' man and advisor put small amounts on the bleed screw threads that go into the ali. brembo calipers - seems to make removal of them and prevent shearing off/ rounding of the 11mm nut a thing of the past.

 

[Hilux]

I've had 2 x 944's both with alloy wheel nuts, total ownership > 10yrs - never had a problem with them.

If the anodising/coating starts to go grey change them I have been told by a few people who should know. Never found out exactly why but I understand its a sign of fatigue.

 

[tref]

Re the copperslip/no copperslip debate, I sware by the stuff, used sparingly, where-ever threadlock isn't required, however... I must admit that for wheel nuts and bolts I have gone back to conventional high melting point grease. The reason is two-fold. First is purely subjective, but it "feels" nicer doing them up and undoing them - the threads feel smoother, less "gritty". To me at least. Secondly, on wheel "bolts" rather than wheel nuts, I have found that brake dust sticking to copperslip on the little bit of exposed thread at the back of the hub seems to stick harder to the bolt with copperslip than with grease. Obviously this doesn't apply to 944s, and not every-one cover the mileages I do to notice this type of thing, but it can be a significant pain! One other thing, having a real good go at cleaning up the studs carefully, right to the bottom, of all the old crud and grease can make the world of difference... it feels like I'm the only person to do so, as I have yet to buy a car with clean wheel studs! Tref.

 

[Super_Marv]

ORIGINAL: tref One other thing, having a real good go at cleaning up the studs carefully, right to the bottom, of all the old crud and grease can make the world of difference... it feels like I'm the only person to do so, as I have yet to buy a car with clean wheel studs! Tref.

Good point Tref - at £80+ for new wheel bolts, you'd be silly not to clean up the studs properly, before fitting the new ones!