A6 / S6 (C6 Platform) Discussion Discussion forum for the C6 Audi A6 produced from 2004-present and Audi S6 produced from 2007-present

How to check brake disc thicknesses

 
Old 01-27-2019, 10:42 PM
  #1  
AudiWorld Member
Thread Starter
 
Join Date: Jul 2017
Posts: 229
Default How to check brake disc thicknesses

I've read a couple of previous threads and understand the brake discs on our cars come in various thicknesses, but how can I check what the correct thickness for my car is? Is there an online checker I could use, or is it irrelevant anyway, as I guess the original build specification doesn't necessarily apply as I don't know if someone has fitted different thickness brake discs in the past?

so is it a case of just measuring their thickness at various points and looking for a delta, of so how much variation in disc thickness should cause you to replace them? Thanks
Sverige is offline  
Old 01-28-2019, 10:36 AM
  #2  
Audiworld Junior Member
 
Join Date: Dec 2018
Location: Austin,TX
Posts: 47
Default

Originally Posted by Sverige View Post
I've read a couple of previous threads and understand the brake discs on our cars come in various thicknesses, but how can I check what the correct thickness for my car is? Is there an online checker I could use, or is it irrelevant anyway, as I guess the original build specification doesn't necessarily apply as I don't know if someone has fitted different thickness brake discs in the past?

so is it a case of just measuring their thickness at various points and looking for a delta, of so how much variation in disc thickness should cause you to replace them? Thanks
check the rotor surface with dial calipers. I thought the difference in rotors were their diameter not the thickness? Maybe Iím wrong.
Klaus Von Richter is offline  
Old 01-28-2019, 12:45 PM
  #3  
Audiworld Junior Member
 
09mazda6's Avatar
 
Join Date: Nov 2017
Posts: 29
Default

Originally Posted by Klaus Von Richter View Post


check the rotor surface with dial calipers. I thought the difference in rotors were their diameter not the thickness? Maybe Iím wrong.
I agree - from the audi.com parts website I believe that the A6 Avants and the S6 have larger rotors in part because of their extra weight and performance respectively. on Audi USA at least if you put in your VIN it does a good job of picking the right parts (not perfect).
09mazda6 is offline  
Old 01-28-2019, 12:53 PM
  #4  
Audiworld Junior Member
 
Join Date: Dec 2018
Location: Austin,TX
Posts: 47
Default

I just measured my diameter with a tape measure. It was 320mm on my A6 Quattro.
Klaus Von Richter is offline  
Old 01-29-2019, 11:02 PM
  #5  
AudiWorld Member
Thread Starter
 
Join Date: Jul 2017
Posts: 229
Default

Ok thanks guys. So if the variation is in diameter rather than thickness, what thickness will be the wear limit, indicating the discs should be replaced?

In in this case I just need to measure the diameter and thickness of the currently fitted discs and then I should be set to order replacements if needed.
Sverige is offline  
Old 01-31-2019, 06:55 AM
  #6  
AudiWorld Super User
 
beep-beep's Avatar
 
Join Date: Jan 2001
Posts: 7,362
Default

Originally Posted by Sverige View Post
I've read a couple of previous threads and understand the brake discs on our cars come in various thicknesses, but how can I check what the correct thickness for my car is? Is there an online checker I could use, or is it irrelevant anyway, as I guess the original build specification doesn't necessarily apply as I don't know if someone has fitted different thickness brake discs in the past?

so is it a case of just measuring their thickness at various points and looking for a delta, of so how much variation in disc thickness should cause you to replace them? Thanks
​​​​​​You need to put new pads when you replace disks. From this point of view you should replace disks whenever you replace pads. Usually disks can last for two sets of the pads. Means you need to replace disks every second pad set. But bmw suggests to put new disks every pad change.


​​​​
​​​​
beep-beep is offline  
Old 01-31-2019, 07:37 AM
  #7  
AudiWorld Member
Thread Starter
 
Join Date: Jul 2017
Posts: 229
Default

Originally Posted by beep-beep View Post
​​​​​​You need to put new pads when you replace disks. From this point of view you should replace disks whenever you replace pads. Usually disks can last for two sets of the pads. Means you need to replace disks every second pad set. But bmw suggests to put new disks every pad change.


​​​​
​​​​
thwnks, I will probably not worry so much about how to check for disc wear and just go ahead and replace them, with new pads also, next time I change back to summer tyres.
Sverige is offline  
Old 02-07-2019, 09:05 PM
  #8  
AudiWorld Member
Thread Starter
 
Join Date: Jul 2017
Posts: 229
Default

So I want to go ahead with changing discs and pads in around a month or two. Right now I just need to figure it how to buy the right parts. If I take off one wheel and measure the disc diameter can I safely assume all the others will be the same? No difference between front and rear axle specs?


Sverige is offline  
Old 02-08-2019, 12:39 AM
  #9  
AudiWorld Member
Thread Starter
 
Join Date: Jul 2017
Posts: 229
Default

Going through the receipts from the previous owner I see rear discs were replaced at 153k km, about 18,000 miles ago, so right now I'm planning on only changing the front discs and pads. Both front and rear pads were also replaced at the same time 18,000 miles ago, but as the fronts take more load I'll change them with the discs.
Sverige is offline  
Old 02-08-2019, 07:49 AM
  #10  
Audiworld Junior Member
 
09mazda6's Avatar
 
Join Date: Nov 2017
Posts: 29
Default

can't say for Allroad but on my c6.5 avant the front and rear rotors are different sizes - best best go to Audi.com and use your VIN or year, model etc to drill down to the right parts. Also at least on my car it appears that my rear pads are wearing faster than the fronts so you should check rear pad thickness as well.
09mazda6 is offline  

Thread Tools
Search this Thread
Quick Reply: How to check brake disc thicknesses


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: