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Home >> Porsche >> 2019 >> Cayenne S >> Repair and Diagnosis >> Brakes >> Mechanical - Hydraulic >> 46 Brakes - Brake Mechanism 2.9L -- 9YA - Cayenne (9YA) >> WM, 465302 Checking Rear Brake Discs (Grey Cast Iron) >> Checking >> Checking Rear Brake Disc (Minimum Thickness)

Checking Rear Brake Disc (Minimum Thickness)

Information 

Normally, brake discs are used until the maximum wear dimension is reached.

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). Only the brake disc dressing machines approved by Porsche AG may be used.

As the pressure force of a brake piston on the brake pad vanes 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.

-B-  Central wear area.

G15292417Courtesy of PORSCHE CARS NORTH AMERICA, INC.

Wear areas A and B

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

G15292418Courtesy of PORSCHE CARS NORTH AMERICA, INC.

Wear area B

Measure the brake discs using a suitable micrometer screw at least 3 different places (-A, B, C-  ), offset by 120°.

G15292419Courtesy of PORSCHE CARS NORTH AMERICA, INC.

Measurement points for brake disc thickness