Service Aktion 46F2 for all Audi cars with ceramic brake system

[harald]

Here in Germany we have just a service –action called 46F2 concerning all Audis with a built in ceramic brake system, because a lot of drivers complained about a crackling sound from the front axle. Some cars even encountered a break of the rotors.
This service will exchange the connection elements of the brake discs to reduce the clearance.
Call your dealers and ask for it before your ceramic brake will burst

Have a nice weekend

Harald

[Europrice]

Harald,

The issue appears to be the design of the attaching/floating hardware of the aluminum hats to the ceramic discs. There are 3 iterations of the front and rear ceramic rotors for the R8 already and each has a different design of this hardware. Any crackling or clicking sounds usually indicate loose hardware or too large a tolerance, though that "loose" fitment is to allow for expansion of the disc at higher temperatures, within reason. Tension is kept on the hat/disc junction to make the discs silent, though too loose a tolerance can cause issues. If you see below you can see the original design:



Here is the very latest design:



You can see the redesign of the hat, bobbin and hardware in the circled areas. They've even redesigned the rear rotors in a similar way:

Early design:



Very latest design:



Sounds like they are changing the hardware to be more like the latest design, though I wonder if they are replacing the hat at all to the latest design or just a hardware redesign. I have customers on the older style who have had no issues, though clacking noises shouldn't be ignored with any two piece rotor. Those noises can indicate loose hardware which can be catastrophic for discs, though some low level clicking is normal for some two piece rotors. Genuine race rotors can sound absolutely terrible when rolling slowly, like the rotors are going to come flying off any moment. This is because some discs do not use any spring to keep tension on the mounting hardware/bobbin so they have completely resistance free room for expansion and movement.

Do you have any pictures of the modifications they are doing to the older discs?

Thanks!

[harald]

Alex,

my dealer showed me the instructions on his computer when I brought my car in. So I haven't any pictures or further informations. As I could see it is exactly as you have described it. They had changed the hardware elements which you have encircled to reduce the tolerance. As I was told it depends on the VIN if these issue is necessary or not.

Harald