A461466 2022584-

Technical Service Bulletin
46 Brake pulsation diagnostic guidelines
46 14 66 2022584/4 January 9, 2014. Supersedes Technical Service Bulletin Group 46 number 12-23 dated June
18, 2012 for reasons listed below.
Model(s)
Year
VIN Range
Vehicle-Specific Equipment
All
2006 - 2014
All
Not Applicable
Condition
REVISION HISTORY
Revision
Date
Purpose
4
-
Revised header data (Changed model years)
Revised Service (Added images; updated instructions)
3
6/18/2012
Revised header data (Added model year 2013)
2
1/18/2012
Revised header data (Updated VIN ranges)
1
1/27/2010
Original publication
Customer may report that the steering wheel vibrates or pulsates when the brakes are applied.
Technical Background
Brake-related vibration and pulsation has several causes that depend on driving style and resulting brake disc
temperature, as well as environmental conditions.
Both the intensity of the wear of the brake system and the type of wear depend on the operating conditions of the
vehicle. The wear of the brake discs is determined by the frequency and intensity of the brake operations. Dirt
build-up, exposure to sand, long standing times, and road salt or similar, can also promote wear as well as cause
scoring marks on the brake discs.
The driving style of the driver also influences the wear of the brake system. An overly-aggressive driving style,
which results in frequent sharp braking, can lead to more wear (particularly of the brake pads). A gentle driving
style can result in very light brake applications. If the brakes are always applied with little pressure, a rust film and
other airborne particles may settle on the brake discs and pads. Firm brake operations can help clean off such
build-up from the brakes.
Production Solution
Not applicable.
© 2014 Audi of America, Inc.
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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
Service
1. Before proceeding, check for other applicable TSBs.
2. Confirm the complaint with a test drive. Check the following points:
• At what speed does the vibration/pulsation start?
• At what speed does the vibration/pulsation stop?
• How much pedal pressure needs to be applied for the vibration/pulsation to be felt (light/medium/heavy)?
• Is the vibration/pulsation felt or seen:
• In the steering wheel?
• In the brake pedal?
• In the seat?
• In the front of the vehicle?
• Does the vibration/pulsation also occur when the vehicle is coasting (not in gear) at the speeds established
in the first point?
• For warranty claims:
• Perform the procedure shown in the Brake Pulsation Service Tree (attachment 1) and attach one
completed copy to the repair order and one copy to the causal part being replaced.
• Use the appropriate Brake Measurement Form to document brake disc and pad thickness. Attach one
completed copy to the repair order and one copy to the causal part being replaced.
3. Diagnose according to the list of conditions listed below:
• Condition A: Brake disc thickness variations (DTV) (Figure
1) or parallelism after certain mileage that cannot be
detected with normal workshop methods. There is no Audi
specification for DTV/parallelism.
Service: Replace brake disc(s).
Figure 1. Brake disc thickness variations.
© 2014 Audi of America, Inc.
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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
• Condition B: Excessive brake disc or wheel hub run-out
(Figure 2). Industry guidelines for run-out are as low as
.04mm to .13mm (.0015in to .005in).
Service: Determine if the run-out is caused by the hub or by
the actual brake disc(s). Replace brake disc(s).
Figure 2. True rotor rotation (A) and rotor
lateral run-out (B).
• Condition C: Corrosion/rust build-up on brake discs (Figure
3) because the vehicle was not driven for prolonged periods
of time.
Service: Follow the procedure outlined in the Brake
Pulsation Service Tree.
Any rust build-up that occurred because inventory
maintenance (as outlined in the Inventory Maintenance
Checklist) procedures were not performed will not be
covered under Warranty.
Figure 3. Corrosion/rust build-up.
• Condition D: Corrosion marks from brake pads on the brake
disc, also known as “pad marks” (Figure 4). These marks
may appear if the vehicle has not been driven for a
prolonged period of time.
Service: Follow the procedure outlined in the Brake
Pulsation Service Tree.
Figure 4. Corrosion marks on the brake
disc.
© 2014 Audi of America, Inc.
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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
• Condition E: Deposits on the brake disc (Figure 5) due to
thermal stress. Thermal stress is when the brake pads
overheat as a result of aggressive driving,
Tip: If the vehicle is driven aggressively, the brakes
must be cooled down before the vehicle is parked for an
extended period of time. The driver can cool the brakes by
driving around with minimal braking before parking the
vehicle.
Service: Damage to the brake components due to
aggressive driving is not covered under warranty.
Figure 5. Deposits on the brake disc.
• Condition F: Worn brake pads and discs (Figure 6) have
reduced dampening characteristics.
Service: Try replacing the brake pads if they are at least
50% worn. If the replacement brake pads do not improve the
condition, replace the brake discs.
Normal wear and tear of brake components is not covered
under warranty.
Figure 6. Worn brake pad.
• Condition G: Blue-tempered brake discs or brake discs with
heat marks (Figure 7) exhibit extremely high thermal loading
of the brake system (with distortion and structural change of
the brake discs). This high thermal loading results in
permanent damage to the brake discs and brake pads.
Tip: If the vehicle is driven aggressively, the brakes
must be cooled down before the vehicle is parked for an
extended period of time. The driver can cool the brakes by
driving around with minimal braking before parking the
vehicle.
Service: Replace brake disc(s). This type of damage is not
covered under Warranty.
Figure 7: Brake disc with heat marks.
© 2014 Audi of America, Inc.
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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
• Condition H: Wheel/tire imbalance (Figure 8) or radial run-out
can significantly amplify vibration/pulsation or lead to body
vibrations, which only become noticeable when braking.
Service: Eliminate wheel and tire vibration concerns by using
VAS 6230 and any relevant TSBs.
Figure 8. Wheel/tire imbalance.
• Condition I: Faulty or damaged suspension components (e.g., ball joints, tie rods, bushing, etc.) can
significantly amplify the vibration/pulsation or lead to body vibrations which only become noticeable when
braking.
Service: Inspect the condition of these components. All values must be within factory specifications.
Ensure that only OEM components are on the vehicle. Damage due to outside influence is not covered
under Warranty.
Warranty
This TSB is informational only and not applicable to any Audi warranty.
Additional Information
All parts and service references provided in this TSB (2022584) are subject to change and/or removal. Always
check with your Parts Department and service manuals for the latest information.
© 2014 Audi of America, Inc.
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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.