BMW AUC Brake Disc Tolerances
BMW AUC Brake Disc Tolerances
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scz4

Original Poster:

2,839 posts

271 months

Friday 22nd January 2021
quotequote all
Morning all,

I bought a 2017 F11 530d earlier this month from a BMW dealer. Car has done 37.5k miles.

It was of course prepared to AUC standards. However, I raised a concern to them with regards to the condition of the front discs, they were corroded, have a lip on them, faint vibration and clearly original. Based on previous experience I would expect discs to last between 35k to 40k in a heavy car like this.

I asked for the AUC report, which they finally provided, see below. So if I read that correctly, they should be replaced at 34.4mm, but just so happened to measure in at 34.5mm. Looking at RealOEM.com the original brakes are 348x36, so I assume 36mm thick. Should I continue to push BMW for replacements? To me they are 94% worn (0.1mm left from a life of 1.6mm).



Edited by scz4 on Friday 22 January 11:27

130idvg

66 posts

218 months

Friday 22nd January 2021
quotequote all
Definitely deal with the dealer you bought from directly. I would certainly be pushing for at least a significant contribution to the cost. May depend a little on how much you hammered them down on price too - if they didn’t make any money on the car, they may be a little more reluctant.

thatdude

2,660 posts

157 months

Friday 22nd January 2021
quotequote all
I think there is good argument to push for those to be changed, as they are practically on the wear limits. It seems senseless to ignore 0.1 mm (and indeed, suspicious).


Smuler

2,288 posts

169 months

Friday 22nd January 2021
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It’s the BMW Approved dealer to deal with. I had an issue and mine were rectified that route.
As my issue would have been eased by using recovery , I contacted BMW U.K. customer services and they didn’t want to know. I’ve heard similar from others.
The pads look low too.
What’s the mileage to change on iDrive. How close is that to the threshold on the AUC sheet.
Good luck. I believe you have a case.

scz4

Original Poster:

2,839 posts

271 months

Friday 22nd January 2021
quotequote all
Unfortunately I don't think I'll have much joy based on this information I've obtained which clarifies things:


"The acceptable amount of wear on a disc before a disc needs replacing is 36mm less 2.4mm so minimum disc thickness 33.6mm.

The acceptable amount of wear on a disc before pads can be replaced (using same disc) is 36mm less 1.6mm so minimum disc thickness of 34.4mm. This is the thickness stamped/etched on the disc.


If you need new pads then the discs should be replaced also, if you don't need pads, then you are ok."

ashenfie

3,320 posts

76 months

Wednesday 27th January 2021
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The Disc's will have the min thickness stamped on them. Simple job to check.