Audi A3 8L: Rear Axle Brake Problems & Solutions

Hello everyone,

"My rear brakes on my A3 are causing me problems regularly. Just a few weeks ago, I had to replace the brake discs and pads because the discs were completely rusted over during the winter. This isn't because the car is driven too infrequently, as I think driving almost 100 km per workday is quite a lot. Nevertheless, the rear discs always rust completely, and the pads also tend to stick quite firmly in their guides."
I was only able to use the previous brake discs for just under a year before I found their condition (and the noise they made when braking) to be unacceptable, so I replaced the discs and pads.
Now I could see the same trend again on the new rotors: The brake pads seem to only make proper contact with the outer edge of the rotors. The inner third of the rotors already shows significant rust buildup, which is not removed during braking. It appears that the pads are being pressed against the outer edge more strongly than the inner edge. This uneven pad contact leads to the described wear pattern on the rotors.

"With me, the new linings are always installed correctly, and the guides are treated with anti-seize compound. However, I believe that the rust formation under the guide plates could be causing the described effect. When I replace the linings, I also remove the guide plates to clean them and the guide surface underneath. The lining holder in this area always shows significant rust buildup, which, on the one hand, promotes the jamming of the linings and, on the other hand, could also cause them to be misaligned."

"Does anyone among you have experienced the problem I described with their A3 or Golf 4?"
Who has found a permanent solution?

I'm considering replacing the brake pads and shims, hoping that will finally solve the noise issue at the rear axle.

I would be grateful for any tips, experiences, or suggestions.

Regards,
Alex.

I experienced this issue with both my old A3 and still have it with my current G3. I haven't had this problem with my Passat (yet!). It seems to be a known issue.

I'm assuming that the issue is truly a matter of the toppings sticking together and that there are no other mechanical problems (e.g., the saddle or its guide is stiff).

Using proper brake grease, a brake file (until the guide is perfectly clean), and regular checks can help. As soon as I see or suspect it might happen again, I immediately remove the pads, clean them, and apply grease, then reinstall the same pads (as long as there's still material left). Usually, I'll need to open them up again after 1-2 years.

Since then, I've been able to drive my pads and rotors until they reach the wear limit. It requires a little effort, but it saves money.

Oh oh... that brings back memories.

What discussions did my former apprentice and my former master have during my training about these guide/sliding plates ?

With my friend, I simply omitted the metal parts due to the annoying noises they made.
He has been using it for over 2 years, and it has been noise-free and accident-free.

Hello,
The fact that the SBB (Swiss Federal Railways) only carries the load on the outside suggests to me that they cannot easily slide back in their guides. If the guide plates are missing, the lining can rattle and repeatedly knock off the rust. However, a more elegant solution is to remove some rust from the guides, lubricate them, and install new plates.
The sheets can also be easily cleaned with a wide screwdriver (which is what I always do with the T4). If the coating on the surface is no longer present, it will naturally rust much faster.
After seeing repeated complaints in other forums about rusty rear brake rotors, and noticing that mine were also starting to rust, I started using the parking brake to bring the car to a complete stop more often, and since then, the rotors have been nice and clean!
@donalexo
If you're already changing your brakes yourself, it's a small job: when you change your tires to winter tires, take the brake pads out, clean them, remove any rust, lubricate them, and put them back in.
It also seems important to me to brake the blocks properly before storing them for an extended period.
I would only replace the leveling compound guide if it's clearly worn out and no longer guides the compound evenly, but I don't think that's the case.

Quote:

This isn't necessarily because the car is driven too infrequently, because I think that driving almost 100 km per workday isn't exactly very little.

Nevertheless, the rear windows always rust completely, and the brake pads also tend to stick relatively tightly in their guides. }

I have often observed such phenomena in vehicles that are parked on damp surfaces (e.g., porous asphalt). Vehicles that are driven in areas where a lot of salt is spread in the winter are also more susceptible to all types of rust.

There are likely differences in rust susceptibility among brake discs, depending on the manufacturer.


It is also common for the coating on linings to corrode in the area of the guides. For this specific area, I believe copper paste provides the best rust protection, as long as it does not come into contact with aluminum.