Checking Grey Cast-Iron Brake Discs - Evaluating Cracks

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2019 Porsche 911, 2018 Porsche 911, 2017 Porsche 911, 2016 Porsche 911, and 2015 Porsche 911. However, it is still accessible from the selected car via links, so may be relevant.

No need to replace brake disc as the perforation crack length is small (less than 5 mm).

Fig 1: Perforation Crack Small Length (Less Than 5 Mm)

Courtesy of PORSCHE CARS NORTH AMERICA, INC.

Some perforation cracks are over 7 mm long.

Brake disc must be replaced (maximum permitted perforation crack length is 5 mm)!

Fig 2: Identifying Perforation Big Crack Length (Greater Than 5 Mm)

Courtesy of PORSCHE CARS NORTH AMERICA, INC.

Brake disc with cracked friction plate rim -arrow- . Brake disc must be replaced!

Fig 3: Locating Friction Plate Rim Damaged Area

Courtesy of PORSCHE CARS NORTH AMERICA, INC.