A4521232065341_1

Technical Service Bulletin
45 Brake discs surface cracks - steel brakes with tungsten carbide coating
45 21 23 2065341/1 December 13, 2021.
Model(s)
Year
VIN Range
Vehicle-Specific Equipment
Audi e-tron
GT, Audi
RS e-tron
GT
2022 - 2023
All
Steel brakes with tungsten carbide coating
Condition
Customer states:
 Cracks on the friction surface of the tungsten
carbide brake disc (Figure 1).
Figure 1. Brake disc surface cracks.
Workshop findings:
 The issue can be confirmed by the dealership.
Page 1 of 2
© 2021 Audi of America, Inc.
All rights reserved. Information contained in this document is based on the latest information available at the time of printing and is subject to the copyright and other intellectual property rights
of Audi of America, Inc., its affiliated companies and its licensors. All rights are reserved to make changes at any time without notice. No part of this document may be reproduced, stored in a
retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, nor may these materials be modified or reposted to other sites, without
the prior expressed written permission of the publisher.
Technical Service Bulletin
Technical Background
On the tungsten carbide brake disc, the friction surface (hard metal layer) is applied to the brake disc using a
special process.
As a result, there are different temperatures and thermal expansions between the hard metal layer and the base
disc while the brake system is in use.
When these different expansions are compensated for, a network of fine, surface cracks appears (relaxation
cracks).
The cracks are normal and have no negative impact on the functions or comfort of the brake system (Figure 1).
Production Solution
Not applicable.
Service
Not applicable.
Warranty
This TSB is informational only and not applicable to any Audi Warranty.
Additional Information
All part and service references provided in this TSB (2065341) are subject to change and/or removal. Always
check with your Parts Department and/or ETKA for the latest information and parts bulletins. Please check the
Repair Manual for fasteners, bolts, nuts, and screws that require replacement during the repair.
©2021 Audi of America, Inc. All rights reserved. The information contained in this document is based on the
latest information available at the time of printing and is subject to the copyright and other intellectual property
rights of Audi of America, Inc., its affiliated companies, and its licensors. All rights are reserved to make changes
at any time without notice. No part of this document may be reproduced, stored in a retrieval system, or
transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, nor may
these materials be modified or reposted to other sites, without the prior expressed written permission of the
publisher.
Page 2 of 2
© 2021 Audi of America, Inc.
All rights reserved. Information contained in this document is based on the latest information available at the time of printing and is subject to the copyright and other intellectual property rights
of Audi of America, Inc., its affiliated companies and its licensors. All rights are reserved to make changes at any time without notice. No part of this document may be reproduced, stored in a
retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, nor may these materials be modified or reposted to other sites, without
the prior expressed written permission of the publisher.