Check Brake Discs For Wear - AR42.10-P-0264-01RG

Model 167, 190 (except 190.381), 197, 205, 212, 213, 218, 223, 231, 232, 253, 290 with code B07 (AMG - ceramic brake system) 

Risk of injury  to skin and eyes from laser beams

Never look directly into the laser beam. Do not attempt to suppress natural reflex of closing the eyelids. Avoid direct skin contact with the laser beam. If damage to the eye is suspected, consult an eye specialist immediately.

AS30.30-Z-0001-01A

Courtesy of MERCEDES-BENZ USA

Before starting the measurement, Check calibration of measuring equipment (2) using supplied test plate (2.1). Make sure that no external electromagnetic fields are present in the area of use of the measuring equipment (2). Use measuring equipment (2) within the specified operating temperature range only.

1. Switch on measuring equipment (2) and place into both positioning openings of test plate (2.1).

   The displayed measurement value must match the reference value (2.2) on the adhesive label attached to the test plate (2.1). A deviation of ± 2.0 units CQ (Carboteq value) is permissible. If the deviation exceeds ± 2.0 units of CQ (Carboteq value), perform a reset procedure on the measuring equipment (2) in accordance with the operating instructions. If the reset procedure of the measuring equipment (2) fails, calibrate the measuring equipment. For proper calibration, send the measuring equipment (2) to a service center that is certified by the manufacturer.

2. Position measuring equipment (2) absolutely flush with the outer edge of the brake disc (1).
3. Move the measuring equipment (2) along the curved radius of the brake disc (1) until the laser beam is aligned with the measurement marking (3) engraved on the brake disc (1). The brake disc (1) must be dry during the measurement. Otherwise, there may be deviations in the measurement result. The displayed value must be between the new value (4) and the wear limit (5) attached to the brake disc (1). If the wear limit (5) is undershot, replace the brake disc (1).

   If only one brake disc (1) is replaced on the front or rear axle because of damage, a wear value of 33 percent of the difference between the new value (4) and the lower wear limit (5) applies to the second brake disc (1) on this axle.

   It is not necessary to remove the brake caliper. Only measure the outside of the brake disc (1). The outside is subjected to a higher thermal load and therefore, with regard to the Carboteq limit value, is always more critical than the side facing the vehicle.

   The measuring equipment (2) contains a class 2 laser. It is essential to observe the safety information in the manufacturer's operating instructions.

   If this value is undershot at one of the 3 measurement markings, also replace the second brake disc (1) of the axle.

   Example calculation 

   Courtesy of MERCEDES-BENZ USA

4. Freeze the display of the measuring equipment (2) in order to be able to read off the measurement value even after the measurement.
5. Turn brake disc (1) and perform a wear measurement at the remaining engraved measurement markings (3) as described in operation steps 3 and 4.

The measurement does not replace visually inspecting the brake disc (1) for damage.