Checking front brake discs (minimum thickness)

NOTE: Normally, brake discs are used until the maximum wear dimension is reached. → 46 Technical data/brake wear limits Only in a few exceptional cases is it advisable to skim the brake discs (if there is deep scoring or corrosion of the friction surface). In this case only the disc brake dressing machines approved by Porsche AG are to be used (see Workshop Equipment Manual, Chapter 3.4).

Only as new brake discs may be reworked!
Only rework the brake discs symmetrically, evenly from both sides!

As the pressure force of a brake piston on the brake pad varies in magnitude, different areas of wear arise on the friction surface. The brake disc can basically be divided into two areas of wear:

-A- Outer and inner wear area. See Fig 1.

Fig 1: Wear areas A and B

Courtesy of PORSCHE OF NORTH AMERICA, INC.

-B- Central wear area. See Fig 1.

Fig 2: Wear area B

Courtesy of PORSCHE OF NORTH AMERICA, INC.

The central wear area -B- is the area with the highest degree of wear. See Fig 2.

Fig 3: Measurement points for brake disc thickness

Courtesy of PORSCHE OF NORTH AMERICA, INC.

- Measure the brake discs with a suitable micrometer at a minimum of three different places ( -A, B, C- ), offset by 120°. See Fig 3.