911 Turbo Cabriolet AWD (997) F6-3.6L Turbo (2008)
Brake Rotor/Disc: Testing and Inspection
Front Without PCCB
Checking front brake discs - wear assessment
Brake disc wear assessment - General
The condition of the parts can make replacement necessary under two criteria, depending on the amount of wear on cross-drilled (perforated) brake
discs:
1. Cracks in the cross-drilled friction plate at advanced stage.
2. Brake disc minimum thickness is not attained due to wear (material erosion due to friction).
In practice, both forms of disc erosion occur.
Normally, brake disc replacement is necessary after the thickness falls below the minimum. In rare, isolated cases (of very high loads for long
periods) replacement may be necessary due to crack formation. To a certain extent, these cracks may be rated as not important.
Perforation crack length is too big (greater than 5 mm)
The maximum permitted perforation crack length is 5 mm.
Checking grey cast-iron brake discs - evaluating cracks
No need to remove from the vehicle as the perforation crack length is small (less than 5 mm).
Perforation crack length is small (less than 5 mm)
Some perforation cracks are over 7 mm long.
Brake disc cannot be used (maximum permitted perforation crack length is 5 mm)!