Notes On Evaluating Brake Discs With And Without Wear Holes - AH42.10-P-9406-14A
Model all (4xWD, CAR, smart)
Perforated brake disc with wear bores
The outer wear bore (11), center wear bore (12) and the inner wear bore (13) on perforated brake discs are located 120° relative to one another between the crescent-shaped brake disc bores (14).
Brake disc with wear bores
The outer wear bore (11), center wear bore (12) and the inner wear bore (13) are located 120° relative to one another.
General
Brake discs with wear bores were introduced in assembly production from model series 205 onwards. Therefore, within a model series brake discs with wear bores and brake discs without wear bores can be installed. Mercedes-Benz genuine brake discs are available for the corresponding model series with wear bores only.
The inner wear bore (13) indicates the absolute wear limit. If only the inner wear bore (13) is visible, the brake discs can still be used with the current brake pads, insofar as the brake discs do not exhibit any further problems. New brake pads may no longer be installed.
If the inner wear bore (13) is no longer visible, the brake discs must be replaced.
On each axle the brake disc with the most advanced level of wear should always be used for assessment.
The outer wear bore (11) and center point wear bore (12) indicate the degree of wear. As long as they are both visible, new brake pads can be installed on the brake discs, insofar as the brake discs do not exhibit any further problems.
For brake discs with deeply contoured ridging on the outer edge and with no visible wear bores, the wear limit with the measurement method must be used to check the brake discs, as the brake discs have either no wear bores or they are so worn that they are no longer visible.