Assessing the carbon-ceramic brake disks (CSiC) for wear (CSiC)
- For damage assessment, use the following illustrations (brake disc wear phenomena).
Cracks (low-tension structure) in the brake disk friction surface
Cracks in the brake disk friction surfaces should be considered differently than those in the gray cast iron brake disks. These cracks are not a wear criterion in carbon ceramic brake discs but production-related and already present in new condition.
For this, see also Reference Sample Catalogue. Refer to REFERENCE SAMPLE CATALOGUE FOR ASSESSING VISUAL QUALITY OF CARBON CERAMIC BRAKE DISCS IN NEW CONDITION of carbon ceramic brake discs in used condition.
- The brake disks are each equipped with 6 wear indicators (3 each on the inner and outer sides, see arrows).
- The wear indicators are attached near the outer brake disk diameter at an angle of 120° to each other and can be identified by their surface structure and color shading, which differ from the rest of the friction surface.
- The size of each wear indicator is 2 cm2
The surface structure of the wear indicators (1) changes while the brake disk is being used. The change in this surface structure allows an initial assessment of the wear condition of the brake disk.
Graphic: Brake disc as new
Illustration: driven brake disc
The wear indicators (3 pieces per friction side) provide only an initial indication of the wear (initial assessment).
There could therefore be deviations in the display accuracy of the indicators in connection with a one-sided driving profile (e.g. racetrack, short-distance driving).
Depending on the driving profile, the brake disk loses up to approx. 200 g of its mass due to the effect of temperature and atmospheric oxygen, mainly in the area of the supporting body. This material-specific loss of mass is to be determined by weighing the individual cleaned brake disc. The minimum permissible weight is marked on the brake disc chamber in a durable manner.
Attention!
The decisive factor for the replacement of a CSiC brake disk due to wear is always whether the minimum weight is reached (excluding other damages)!
Follow repair instructions 34 11 220 in the event of exchange.
For edge damages, see "LIMIT SAMPLE CATALOG for assessing carbon-ceramic brake disks in used condition"