Rust on Front Brake Disc (Inside Only)

Hello everyone,

Here's a problem with an Audi A3 8L:

Approximately 15,000 km ago, the front brake discs and pads (FS III) were replaced. The vehicle is driven relatively infrequently.

The outer surface of the discs is in very good and uniform condition, but on the inner side, you can see a rust ring, approximately 5-6mm wide, around the outer edge of the disc (on the contact surface).

"I've seen this issue with the rear brakes on cars like the Golf 4, where the diameter of the brake disc is slightly larger than the brake pads."

However, it's difficult to explain why this is happening. The tiles should also be positioned along the edge of the rust.

What surprises me about that is:
The brake piston initially presses the inner pad against the rotor. Even if the bolts on the caliper were stuck, the inner pad should still be pressed against the rotor.

Does anyone have any ideas?
The material is from ATE and is suitable for the vehicle.

Best regards,

Holger247

Quote:

The vehicle is likely to be used infrequently.

You've already explained it yourself, and it's always recognizable in people who are low-energy or lack motivation.

The reason the inner brake pad wears out first is due to the design of the brake caliper. The outer brake pad is almost constantly in contact with the rotor, or at least experiences very little pressure.