Checking Rear Brake Discs (Evaluating Cracks)

Brake discs must  be replaced if a crack has progressed as far as the outer and/or inner edge of the disc.

As a precaution, brake discs must be replaced when:

• the > Maximum crack length 0.5 x a mm  is exceeded.
• the > Maximum crack width 1 mm  is exceeded.
• the > Maximum crack depth 1.5 mm  is exceeded.

The maximum crack length limit is calculated as follows: 0.5 x a

Courtesy of PORSCHE CARS NORTH AMERICA, INC.

Width of friction surface

The length of a crack can be measured using a steel rule, for example.

Courtesy of PORSCHE CARS NORTH AMERICA, INC.

Brake discs