Following on from my long term review and comments from another member about excessive brake disc corrosion, I wanted to share my similar experience.

These are images of my brake discs at about 45k miles.

The corrosion builds up and creates a hardened layer of material that chews up the brake pads so they only end up wearing the middle of the disc surface, if that makes sense.

I changed out the discs and pads at 50k miles, but they would have done about 70K miles.

You can pick up genuine brake discs and pads on auction sites easy enough so it’s not too expensive to remedy.

Thanks Andrew,

The fact that the seller of the brake discs cannot spell ‘brake’ correctly, does not instil confidence! 
Incidentally, where do you get your car cleaned? 
Regards,

Gareth.

Lol, I know.

His loss, my gain.

The new discs corrode as much as the old discs so I know they’re genuine ha ha haaa

The car hasn’t been washed in months in that pic on long term review. But the Polish guys at Tesco get to wash it every few months. That’s about it. I’m not too precious with it.

There you go then! His loss may gain?? 

Guessed your car cleaning routine - spray acid over wheels, discs and calipers, before blasting them with a high pressure lance. No wonder your brake components are suffering from premature corrosion issues. 

How come it’s only the front discs then?

30 minutes ago, TOOL said:

How come it’s only the front discs then?

Hi because they are fixed callipers on the front probably six pot and there is no movement in the calliper to let any trapped debris free floating units are far more forgiving, AUDI obviously thought it was a good idea to put track car callipers on a normal car, yes the braking is more progressive but you can loose that advantage after the first 30k as most people never change their fluid which especially on fixed callipers has a dramatic effect on pad/disc wear.

Steve.

Interesting to read that, thanks Steve.

The brake fluid has been changed every 2 years by Audi as per their schedule. The car was under extended warranty until last year for peace of mind.

I’ll show you the condition of the front brakes and pads after 50k miles, as I’ll be honest I’ve never seen this on another car.

Note: I took these pictures after the discs had been sitting dry stored for a while, not straight after they were removed.
You can see just how reduced the brake pad contact surface was. 
I then gave them a scrub with some 60 grade emery paper to see how they would come up.
 

I also measured the disc thickness on the wear surface and they are measuring 34.93mm so only about half worn.

There was still plenty of meat left on the pads too.

18 minutes ago, TOOL said:

Note: I took these pictures after the discs had been sitting dry stored for a while, not straight after they were removed.
You can see just how reduced the brake pad contact surface was. 
I then gave them a scrub with some 60 grade emery paper to see how they would come up.
 

I also measured the disc thickness on the wear surface and they are measuring 34.93mm so only about half worn.

There was still plenty of meat left on the pads too.

Hi nice picture and you obviously have the right kit for the measuring, I used to have a friend that was an instructor for the Nigel Mansell racing school at Sneterton so I had the privilege of spending a lot of weekends there and learnt a lot, what you have is classic wear caused by basically what is a track car set up on a road car, this system is essential on high performance road cars such as Ferrari etc that are running over 400bhp, you could have the discs skimmed but I think you would achieve bottom limit before they cleaned up, my theory for what its worth is if I used genuine discs and pads on my A6 they never lasted that long but the reverse is if I bought ATE high carbon discs and used Brembo pads I got at least a third more wear out of the discs and pads and on a cab thats not bad going, I think on later vehicle Audi have probably done the cost cutting thing with the carbon content for the discs, lets face it they would do this just save money.

Steve.

I think the genuine Audi discs are poor quality. They shouldn’t be wearing like this.

 

I’ll try and find someone local to me who can resurface them on a lathe properly as they’re off the car. Then install them in about another 10k miles.

There will be enough in the discs for another ~40-50k miles imho.

Hi, it seems when searching online for front brake discs on 4M Q7 many places like eurocarparts, autodoc even ebay have the wrong size disc. The front disc size should be 400mm and they come as left and right so part numbers are slightly different. many sites show 350 or 375mm. This might not be correct for all models mines a 3.0 petrol and this is the case. Upon finding the right discs they are well around £600 for the pair, there is a cheap one on ebay i found for £300 but i would not trust that.