Rear caliper carrier bolt replacement.

[Fatbloke]

Hi All

When I get round to fitting my B12 kit soon, I am replacing the front (upgrade to 312mm) and rear disks and pads. What I would like to do is replace the rear triple square caliper carrier bolts with equivalent size/strength standard or allen bolts.

Is there a suitable replacement bolt available?

 

[pburv]

Here is a company we use at work..
https://www.gwr-fasteners.co.uk/
What I would suggest is you use the appropriate grade of bolt..I'm guessing 'high tensile' ?
Find out the exact thread size,length and type ie metric or imperial and then look for high tensile type which is usually marked or labelled 'S'
This article explains the differences...
https://www.gwr-fasteners.co.uk/

 

[Bigjase88]

4.8 is normal bolt
8.8 is high tensile
10.9 is even higher tensile
12.9 is even higher again.

the problem with high tensile bolts is they can shatter quite easy. Drop a 12.9 and i have seen them break

 

[pburv]

Here is a company we use at work..
https://www.gwr-fasteners.co.uk/
What I would suggest is you use the appropriate grade of bolt..I'm guessing 'high tensile' ?
Find out the exact thread size,length and type ie metric or imperial and then look for high tensile type which is usually marked or labelled 'S'
This article explains the differences...
https://www.gwr-fasteners.co.uk/

Not sure what happened with my link on this post??
But this is what I meant to post up...
https://www.workshopwarehouse.co.uk... type of grade,the structural grade for bolts.
As @Bigjase88 has posted above you should be looking for 8.8 (S) grade of bolt.

 

[Fatbloke]

Looks like (if these are correct for the 8v tdi) the bolts are 10.9, M12, 1.5 pitch and 65mm from the bottom of the head.

https://www.autodoc.co.uk/febi-bilstein/9799886

I found 60mm or 70mm mostly but the only 65mm ones I saw were 12.9 tensile strength.

I will have another look. There must be something to ditch the triple square.

Thanks for the info guys. Its very helpful.

 

[Bigjase88]

Yeah 10.9 sounds about right

 

[AlS3BE]

Just out of curiosity, why?
Audi has tested the original bolts and they hold up with the braking systems so why change it? I know it’s only a bolt but it’s part of a tried and tested safety system and you you don't want to put a potentially sub standard bolt in place. Don’t think they are that expensive from Audi either.

 

[Fatbloke]

Just out of curiosity, why?
Audi has tested the original bolts and they hold up with the braking systems so why change it? I know it’s only a bolt but it’s part of a tried and tested safety system and you you don't want to put a potentially sub standard bolt in place. Don’t think they are that expensive from Audi either.

Because triple square is a pain in the rectum , especially with limited access to hold the tool straight, apply pressure to hold it in and turn it. An Allen set screw of the same strength is much easier to deal with.

 

[AlS3BE]

I’m just playing devils advocate but regardless of the end of the bolt, triple square or hex, the space and other restrictions for tools is still gonna be the same. Just using a different end/socket. a new tool is possibly cheaper/safer than New bolts of unknown origins. I always like having new tools though even though I might only use them once
Not had issues with triple squares before but I’ve not fitted brakes for years as managed to get rid of cars before I needed brakes. Saying that I’m planning on keeping my s3 so will let you know if it becomes a pain in the near future.