Single use bolts!

4.2 V8 32v Naturally Aspirated - 414 bhp
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James1984
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Single use bolts!

Post by James1984 » Thu Dec 27, 2018 11:41 am

Im doing a refresh of the rear subframe and all the control arm bushes and the bolts are listed as single use, im going to tps today to get a price on them but already had a price elsewhere at £157, pricey for 16 bolts so im wondering who actually replaces them? I was originally thinking of fitting new eccentric bolts and new locking nuts on all the other bolts but im thinking i should probably replace? Whats peoples view on this?

jon_273
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Re: Single use bolts!

Post by jon_273 » Sun Dec 30, 2018 4:40 pm

You could just clean them up and use some Loctite threadlock.

James1984
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Re: Single use bolts!

Post by James1984 » Sun Dec 30, 2018 7:39 pm

jon_273 wrote:
Sun Dec 30, 2018 4:40 pm
You could just clean them up and use some Loctite threadlock.
My main concern is the plus 90 degrees on the bolts, the torque setting is 85nm plus 90 degrees whereas the torque for a m14 bolt is 180nm, so i would like to know if the plus 90 degrees takes the bolt past the 180nm.

eljay
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Re: Single use bolts!

Post by eljay » Mon Dec 31, 2018 2:33 am

I can’t comment from what people normally do, but when a bolt says single use it’s because the application will have used up the bolt’s elasticity required to maintain the correct tension. Attempting to retighten a bolt that’s been tightened at that level will result in breakage either at the time or in the future. Essentially it’s stretched and can’t come back to shape for another go.

I’d replace them if it says to, if you want a troublefree fiture. You may get away with it, but is it worth it?

James1984
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Re: Single use bolts!

Post by James1984 » Mon Dec 31, 2018 10:20 am

eljay wrote:
Mon Dec 31, 2018 2:33 am
I can’t comment from what people normally do, but when a bolt says single use it’s because the application will have used up the bolt’s elasticity required to maintain the correct tension. Attempting to retighten a bolt that’s been tightened at that level will result in breakage either at the time or in the future. Essentially it’s stretched and can’t come back to shape for another go.

I’d replace them if it says to, if you want a troublefree fiture. You may get away with it, but is it worth it?
Probably not worth it, im changing all of the eccentric bolts anyway and they are the most expensive ones, bolts for the rear excluding subframe to body are £160 so every little helps as they say, ive headd a few reasonr why they could be single use such as rust coating, ati friction coating etc but think i will just grit my teeth and take it.

coffey555
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Re: Single use bolts!

Post by coffey555 » Mon Dec 31, 2018 10:14 pm

Are you powder coating the original subframe or fitting a new one?

This is next on my 'to do list' after a full respray so just trying to get an idea of costs.
Misano Red RS4 B7 Avant

James1984
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Re: Single use bolts!

Post by James1984 » Tue Jan 01, 2019 12:51 am

The origional one, havnt had any quotes yet but cant see it being that bad, finish doesn’t have to be perfect for me

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alex760
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Re: Single use bolts!

Post by alex760 » Wed Jan 02, 2019 5:03 pm

James where did you get the torque value of 85nm + 90 degree? I'm swapping my rear subframe bolts as I've just fitted coilovers but I'd read online it 110nm +90?

cheers mate
alex

James1984
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Re: Single use bolts!

Post by James1984 » Wed Jan 02, 2019 5:49 pm

Subframe is 110nm plus 90 degrees, control arms are all 85nm plus 90 degrees with the exception of the eccentric bolts which are 95nm with no extra degrees, i found an online manual with the torque figures, like an online version of the audi workshop manual.

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alex760
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Re: Single use bolts!

Post by alex760 » Wed Jan 02, 2019 7:44 pm

brilliant, cheers james. That clears a few bits up :thumbs:

Shockerboy
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Re: Single use bolts!

Post by Shockerboy » Mon Jan 07, 2019 12:27 pm

Repairing a RS 4 brakes last week i came across a butchereed bolt holding the front caliper on . Wait for it , cant buy this bolt alone you have to buy the calliper and bracket close to £1000.00 ( What are Audi thinking ) sorry bit off topic

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dhali
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Re: Single use bolts!

Post by dhali » Mon Jan 07, 2019 1:21 pm

Shockerboy wrote:
Mon Jan 07, 2019 12:27 pm
Repairing a RS 4 brakes last week i came across a butchereed bolt holding the front caliper on . Wait for it , cant buy this bolt alone you have to buy the calliper and bracket close to £1000.00 ( What are Audi thinking ) sorry bit off topic
I take it that is the mushroom head allen key bolts holding the bracket to the caliper?
Have you tried the caliper refurb companies ?

Shockerboy
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Re: Single use bolts!

Post by Shockerboy » Tue Jan 08, 2019 12:41 am

Hi there Dhali I eventually found a specialist bolt company in Wolverhampton who had almost the perfect replacement so a tragedy was indeed avoided .
thanks for the tip , ill be prepared in future ha ha .
Fitted a set of KONI's to the car as well so hopefully client will see massive improvements in handling and braking / collecting tuesday 08

James1984
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Re: Single use bolts!

Post by James1984 » Tue Jan 08, 2019 1:51 am

I still the bolt bot just a m12x80mm long? Shouldn't be that hard to find?

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