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Wear assessment by checking thickness of brake disc > < Brake test

A5

Assessing degree of wear on ceramic brake discs
Assessing degree of wear on ceramic brake discs
  Note
Ceramic brake discs are installed on the front axle only.
Checking area of bolted connection on friction ring and brake disc hub:
  WARNING
The brake disc ring and the brake disc hub are bolted together and must NOT be separated. Do NOT slacken the bolted connection on the brake disc hub.
Designation of ceramic brake disc on brake disc hub
   
1 - Direction of rotation
2 - Supplier
3 - Serial production number of brake disc
4 - Audi part number
  Note
The Audi part number of the brake disc is an example and can vary depending on the vehicle type and model
5 - Production date of brake disc
6 - Permissible minimum thickness of brake disc
  Note
The minimum permissible thickness of the brake disc differs depending on the type of vehicle.
7 - Weight of new brake disc with brake disc hub
Checking area of bolted connection on friction ring and brake disc hub:
  WARNING
The brake disc ring and the brake disc hub are bolted together and must NOT be separated. Do NOT slacken the bolted connection on the brake disc hub.
  Note
The weight of the new brake disc with hub differs depending on the type of vehicle.

The brake disc must first be cleaned before assessing the degree of wear as described below.
  WARNING
Do NOT clean the brake disc with water or other fluids as this will falsify the results.
  Caution
Always observe respiratory protection requirements when cleaning brake discs or other parts of the brake system using compressed air.
  Note
t  The brake disc vent holes must be completely free of brake dust and dirt. Clear out carefully with a suitable tool if necessary. Do not use force.
t  Thoroughly blow out the brake discs with compressed air (including the area between the cooling channels and vent holes).
  Caution
Always observe respiratory protection requirements when cleaning brake discs or other parts of the brake system using compressed air.
To assess the brake disc wear, proceed as follows:
t  1. Wear assessment by checking thickness of brake disc
t  2. Wear assessment on basis of wear indicators
   
1. Wear assessment by checking thickness of brake disc → Chapter
Thickness of brake discs in permissible range → brake disc OK
Brake disc thickness in critical range min. Th + 0.2 mmValue at or below limit
↓↓↓↓
Further wear assessment on basis of wear indicatorsRenew brake disc
↓↓----------
3. Wear assessment on basis of wear indicators → Chapter
None of the six wear indicators fully worn out → brake disc OK
----------One of the six wear indicators fully worn out
---------↓↓
----------Renew brake disc

Always renew brake discs on both sides of axle if:
t  the brake discs have to be renewed because of wear.
t  there has been a technical modification to the replacement brake disc (indicated by changed part number).
If one of the three wear limits defined below has been reached, do NOT continue using the brake disc. The brake disc must be renewed.
In this case, always renew the brake discs on both sides of the axle.
When doing so, always renew the brake pads on both sides of the axle.
   

Wear assessment by checking thickness of brake disc > < Brake test