S3 Rear Brake discs, strange wear

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OliJ

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I've noticed on both my rear discs, what looks like scoring, but it appears to be lines of rust. Not seen this before, I wouldn't consider it normal unless anyone elses look the same? Car only has ~1100 miles on it.

Going to have Audi look at it when i take it in for its (belated) 1000 mile oil change, but the brakes dont squeal when used, car doesnt pull to one side, thoughts?

Fronts are how I'd expect them to be.

20150125 124436 20150125 124523
 
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Does it disappear after you've driven the car for a few miles, if so it is normal...
 
Nope, I've tried firm braking and that doesn't seem to scrub it off.

Perhaps I need to take it out and brake harder...
 
Get a similar sort of thing going on on the wife's MINI John Cooper Works

I normally find a quiet stretch of road and do some hard braking from around 60mph. Sorts the problem for me

Just a thought :thumbs up:
 
I'll try and find a quiet road and brake down hard from 60->0 a few times if possible. See if that helps. Sorta seems as if the pad isnt making smooth contact with the disc.

I dont know how much rear brake bias there is, which might make it more difficult.
 
Not a lot of rear bias.

But you'd increase your effectiveness if you did 60>0 in reverse ;)
 
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Steady on, it's not an Allegro :D

Would pulling the parking brake up apply the rears or just smash on the fronts?
 
Pulling up and holding up on the EPB switch on the move will apply full hydraulic pressure to all 4 wheels, but make sure that there is no one behind you, and you have your seat belt on :)
 
Sounds like fun, do they lock up or does ABS still function?
 
I'll get out there and find somewhere to do some aggressive braking. See if that scrubs the rust off. I think my problem is that the rears hardly get applied, EPB starting at 30 I'm thinking....

Thanks for the info.
 
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Quite a few cars do this, it's often used as an indicator on Imprezza's that the car has had an easy life. Brake really hard a couple of times and it should scrub off. As Veeeight says there's not much rear bias.
 
Broke hard down a few times. The lines have just turned black. So will try a few more times. Then, meh, off to Audi i guess.
 
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audi upgrades
Just had my wheels rotated and took some photos:

IMG 3076 IMG 3078

These are both sides on the rear. The fronts look completely normal. Done just over 20k miles now and not really in the mood to pay for new pads and discs just yet. The outer corrosion rings suggests that the pads weren't aligned correctly to begin with - I'd have expected pad contact across the full disc.

Has anyone experienced similar wear on the rears? Where do I stand with the dealer on this?
 
veeeight said:
ABS still functions.

Everyone should do this at least once, so they aren't surprised if they ever have to do it for real !

Have a read from here:
http://www.audi-sport.net/xf/threads/a3-brakes-and-warnings.210651/#post-2144684
Click to expand...

Sorry to hijack this thread but just had a quick question regarding this feature. Is pulling up and holding on the button just the same as holding down on the foot brake? I am just trying to imagine an emergency situation in my head and reaching and pulling up a button seems far less intuitive than simply putting your foot down hard on the brake...
 
s3_trev said:
Sorry to hijack this thread but just had a quick question regarding this feature. Is pulling up and holding on the button just the same as holding down on the foot brake? I am just trying to imagine an emergency situation in my head and reaching and pulling up a button seems far less intuitive than simply putting your foot down hard on the brake...
Click to expand...


If your foot (hydraulics) brake fails, pulling up and holding up the button will engage both the hydraulic brakes and the electric servo motors of the EPB on the rears, so you are engaging 2 separate braking systems (if one fails).

Akin to in the old days, if you foot brake fails, you would pull up on the cable operated handbrake to give you some braking.
 
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Mine has done the same just on the rears too, My car has also done around 20k!
 
I'm in around 20k and have just noticed the same on my rears, although it's much less obvious on mine. Just had my 19k Inspection Service last Monday and brake pads and discs are listed as being fine with only 25% wear, don't feel anything on the pedal, might try and get it off with the 60>0 runs!
 
I had a similar incident in one of my rear brake discs at my S3. Dealer (at least said that) they found a small piece of rock there and replaced the disc under warranty.
 
Thanks for the feedback! Will mention the wear when I put the car in soon to have a problem with the sound system (no sound!) fixed...see what they say. Good to hear it's not just on mine!
 
Sorry to revive a 7 year old thread. Oh man :grimacing:
But having the exact same issue on my rears. I drive it like i stole it so cant see not braking hard enough is causing the uneven wear.
New OEM Disks only done 10,000 miles mostly all country roads. But look just like the first picture in the thread.
MOT says rear Brake discs worn... as an advisory.
If anyone still has the S3's did you ever solve it? Or is it just how these cars are
 
Try some reverse braking ie reverse down a gentle hill & apply brakes quite sharply. The ABS will kick in quite early as there is little weight over the fronts but a couple of goes and it will scrub the rear discs - I had to do this after first lockdown when the car was hardly used.

That will tell you whether it’s just mild corrosion or something more significant.
 
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