Nuts and bolts

[simon44]

Hi there,

How important is it to use genuine Audi nuts and bolts for attaching the various exhaust parts together over other makes? I notice that the original bolts were rusted tight so we were thinking of trying something different/of better quality and I also notice that a lot of the nuts Audi supply for the exhaust sections are copper, I guess because of the heat from the exhaust.

Any advice on how close to Etka I need to be would be great!

Cheers,


Simon

[S2central.net]

There are fastener specialists who can advise you. Copper stuff is important round the exhaust areas as you say.

Any bolt with numbers on the head - like 10.9 for example - that means its a high tensile bolt. These need to be replaced with similar.

Nylocs need to be observed also - and always renewed where possible.

The only bolts which should be considered Audi only are those of stretch design - like head bolts, strut to hub bolts and a few other places.

[Fat Audi 80]

I have used stainless steel nuts and bolts on my exhaust for years with no problems. My CATS are replaced and removed once a year though, so that helps too. However, I would be more careful to use the correct nuts and bolts on the Ex Manifold and turbo areas, where it gets really hot...

HTH

Cheers,

Steve.

[simon44]

That's brilliant - thanks Guys. I noticed that the bolts for the downpipe to CAT and the bolts from CAT to Y Pipe look the same but have a different number - cant remember exactly but 10.9 and 10.8 so very slightly different which I guess is allowing for the heat differences maybe.

The downpipe to CAT is on with stainless steel bolts and nuts although I now have the Audi ones so wondering whether to leave as is for now and replace later or go for it now. I think the stainless steel ones used are aircraft grade or something like that so quality, but the retentive side of me thinks use the Audi ones.

Many thanks for your help.

Cheers


Simon

[Error404]

I use A4 grade stainless on all non-critical nuts and bolts, cheaper than OEM ones, and will last for ever.

As Paul says, use oem bolts or appropriate high tensile bolts for the criticals, but for exhausts, body and trim fixings, stainless is the badger IMHO

[Keeper of The Kitten]

On the hottest of the exhaust parts, if you can get inconel nuts they are the least likely to get stuck when the time comes to take them off again.

Unfortunately they're also the most likely to cost you an arm and a leg.

Stainless nuts are great but they are prone to galling on installation, be careful with them and never force them if they feel like they are sticking.

Never use anything unmarked (low grade) on critical areas.

[Error404]

What do you mean by "galling" Martin?

[Keeper of The Kitten]

They catch and the thread surface gets torn - stainless nuts have an unpredictable habit of trying to cold weld themselves to the stud they're being threaded onto, hence you should take care with them during installation and never force them.

[Error404]

thanks - I use them quite a bit and never really been overly careful - maybe i've been lucky so far

[Keeper of The Kitten]

It's probably worse when using stainless nuts on stainless studs, but still worth being careful!

[Fat Audi 80]

I have used a lot of stainless steel nuts and bolts in the past and found this only really happen on cheap nuts and bolts. If you have some decent quality ones it is less likely...

[simon44]

Thanks Guys. This post has thrown up some interesting knowledge and top tips. Massively helpful - thank you.

[simon44]

One quick question on this - I notice that at the top of the downpipe where it bolts to the turbo there is one type of Hex nut that also requires a washer then another 3 of another sort of Hex nut that dont require a washer. As I've ordered extra washers would it make sense to fit a washer with all 4 Hex nuts even though Audi dont specify this? (sorry, I havent got the Family Album reference with me but this is page 43 of the pdf manual.)

Many thanks,


Simon