911 Carrera S Cabriolet (997) F6-3.8L (2007)
Checking brake discs for edge damage
Information
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Irrespective of wear, a brake disc change can be necessary on the brake disc friction surfaces due to edge damage.
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In such cases, only one brake disc may need to be replaced if the friction area surface of the other PCCB brake disc is still completely OK.
The following criteria apply to edge damage assessment:
Edge damage on PCCB brake disc
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Max. permissible width/depth = 2 mm
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Max. permissible length = 10 mm
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Max. 3 damaged edge areas permissible
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).