Brake Rotor Thickness, Checking For Wear

WARNING: This page is about a different car, the 2021 Audi S4 and 2021 Audi A4 Quattro. However, it is still accessible from the selected car via links, so may be relevant.

Special tools and workshop equipment required

Commercially available digital caliper or micrometer gauge.

Procedure

Fig 1: Identifying Ceramic Brake Rotor Data

Courtesy of AUDI OF AMERICA, LLC

The minimum permitted brake rotor thickness "min.th." is engraved in the brake rotor cup -3-.

-- Measure the brake rotor thickness -x- three times around the circumference in addition to the individual wear indicators.

Fig 2: Measure Brake Disc Thickness Three Times On Each Wear Indicator Circumference Of Brake Disc

Courtesy of AUDI OF AMERICA, LLC

If dimension -x- = minimum thickness +0.2 mm is reached, also check the wear indicators to determine the brake rotor wear. Refer to WEAR INDICATORS, CHECKING .

CAUTION:

Risk of accident due to insufficient braking action on worn ceramic brake rotors.

Reusing ceramic brake rotors that have reached the wear limit is not permitted.

- Immediately replace the ceramic brake rotors once they have reached one of the wear limits defined below.

CAUTION:

Risk of accident due to uneven braking.

- If a brake rotor is damaged or worn, check the other brake rotors for damage and wear.