ATU 8/2016

2

AUDI AG

INS

Presentation title

Date

Important Reminder

This information is supplemental only.

>

There may be information in this presentation that is not necessarily relevant to the
North American market.

>

Always refer to ELSA for the latest repair information

>

Check for any Knowledge Articles in A.U.D.I. Search

>

Check for any open campaigns or RVU's

>

Check for the latest TSB's

>

Always check ETKA for the correct part numbers

Running gear: Audi magnetic ride - knocking noises from
rear shocks on S3(8V) and TTS(FV)

4

AUDI AG

INS

Presentation title

Date

Audi magnetic ride - knocking noises from rear shocks
Operating principle

Piston bores

Solenoid not
actuated

»

Solenoid
actuated

The shock absorbing dampening is adjusted by changing the input current and
the resulting magnetic field

5

AUDI AG

INS

Presentation title

Date

Audi magnetic ride - knocking noises from rear shocks
Current Customer Complaint

> Complaint

Knocking noises coming from the back of the car when
driving over bumps or on uneven roads.

> Measure

Change the rear shock absorber mounting.

> Part number:

850 513 353 to 8V0 513 353

> Note

Only perform this repair if the vehicle was originally
equipped with part number 850 513 353.

> T5Bs

2042645
2042539

»

53(8V)
TT5 (FV)

The T5Bs listed above are only applicable to vehicles equipped with the Audi
magnetic ride suspension and were built with part 850 513 353.

Brake System: Braking noises - basic principles for
diagnosis and repair

7

AUDI AG

INS

Presentation title

Date

Braking noises - basic principles and countermeasures
Agenda

•

II
II
•

Basics

Countermeasures for squeaking noises

Countermeasures for rattling noises and clicking when reversing

Summary - tips for practical use

8

AUDI AG

INS

Presentation title

Date

Braking noises - basic principles and countermeasures
Basics
The purpose of the brake system is to reliably and comfortably slow the vehicle and to
fully brake the vehicle in an emergency, with the shortest possible braking path and
while retaining the stability of the driving dynamics. Despite continual efforts in brake
development to satisfy all requirements, the brake can generate some annoying noises.
The generation of these noises depends on a variety of influencing factors, which must
be noted in particular when attempting to reproduce the noise.
Environmental conditions:
Climate: dry, wet, warm, cold, snow
Road condition: weather-dependent (e.g. road salt), construction-related
(e.g. cobblestones)
Operating conditions:
Brake temperature
Speed
Brake pressure
Vehicle tires (wheel rim design)

9

AUDI AG

INS

Presentation title

Date

Braking noises - basic principles and countermeasures
Basics

> Noise incidents are normally classified according to frequency band and mechanism
of excitation

> Classification of vibrations when braking:
/
High-frequency
squeaking

"'Cl
Qj

u

::J
"'Cl
C

Low-frequency
squeaking

......
I

Qj

Qj
V)

I

0..

>

+-'

C

~~ ,
>

>
C

,._

I

Groaning,
whining
V
.,...__- - - - - - - - - - - - - - - - - - - - --+-- - - - - - -1

0
+-'

ro

Mooing

-u

I Juddering
High-frequency
faults

a,

u

Qj

::J

LU

·-

x -g

I,,.
10

Low-frequency faults

100

500

lk
Frequency [Hz]

3k

20k

10

AUDI AG

INS

Presentation title

Date

Braking noises - basic principles and countermeasures
Countermeasures for squeaking noises

> Damper/shim plates

> Damper plates, or "shims" may be attached to the backplates of the brake pads.
> These vary in shape and material and are sometimes unidirectional.
> Relevant disc brake pads are marked with an arrow that indicates the direction of
rotation of the brake disc when driving forwards.

11

AUDI AG

INS

Presentation title

Date

Braking noises - basic principles and countermeasures
Countermeasures for squeaking noises

> Adjusting the brake pad (chamfer)

> Chamfers on the brake pad material ensure that the pad is not pressed evenly on
the brake disc

12

AUDI AG

INS

Presentation title

Date

Braking noises - basic principles and countermeasures
Countermeasures for squeaking noises

> Active vibration dampers

> Vibration damper vibrates out of phase with the disruptive excitation.
> An elastomer supporting body performs the damping function.
> Series use, e.g., RS models.

13

AUDI AG

INS

Presentation title

Date

Braking noises - basic principles and countermeasures
Countermeasures for squeaking noises

> Passive vibration dampers

> Natural frequency is offset due to passive components in the brake system.

> Vibration dampers are delivered together with the brake caliper/brake pad and
are not intended for subsequent installation.

> Series use, e.g., 56,57, 58, R8.

14

AUDI AG

INS

Presentation title

Date

Braking noises - basic principles and countermeasures
Countermeasures for rattling and clicking when reversing

> Spring mounting for brake caliper

> Rattling noises and clicking on the brake when reversing are caused by relative
movements of the brake pad in the brake caliper guides. This is usually due to
defective or missing spring elements.

15

AUDI AG

INS

Presentation title

Date

Braking noises - basic principles and countermeasures

Summary - tips for practical use

>> Before performing repair work for braking noises, a frequency analysis
must be performed and the above environmental and operating
conditions must be noted.

>> Precise determination of the source of the noise (front axle/rear axle,
rig ht-side/left-side).

>> Perform repairs exactly as described in the workshop manual or TSB.
>> Brake pads must never be reworked. Manual reworking of the brake
pads, such as grinding or filing, leads to a reduction of the friction
surface and causes mechanical and thermal overload. The effectiveness
of the brake is reduced and wear and noises are increased.

>> Always check pads/discs for unidirectional markings prior to
installation.

Running gear: Multi-collision brake

17

AUDI AG

INS

Presentation title

Date

Multi-collision brake
Agenda
•

II
•

Mode of operation of the multi-collision brake

Use at Audi

Procedure at the dealer

18

AUDI AG

INS

Presentation title

Date

Multi-collision brake
Mode of operation of the multi-collision brake

> Studies have shown that in the event of an accident, the first collision is often
immediately followed by a second collision, either with a vehicle in front, another
road user, or with obstacles such as crash barriers or trees.

> This is where the multi-collision brake intervenes: the multi-collision brake is
activated when two independent sensors detect an accident.

> The airbag control unit then issues a command to the ABS/ESC control unit to brake
the vehicle. After an accident, the vehicle continues to brake independently, even if
the driver no longer actuates the brake pedal. This prevents what could otherwise be
a second collision, or reduces the impact energy of a subsequent collision due to the
reduced speed. The reduced speed also makes the vehicle easier to control.

> The driver can retake control of the vehicle at any time.
> In the owner's manual, this function is referred to as the "Automatic Post-Collision
Braking System".

19

AUDI AG

INS

Presentation title

Date

Multi-collision brake
Mode of operation of the multi-collision brake

> Accident situations in which the multi-collision brake enters into effect:

»

The multi-collision brake can prevent the vehicle from swerving into oncoming
traffic after colliding with the crash barrier.

20

AUDI AG

INS

Presentation title

Date

Multi-collision brake
Mode of operation of the multi-collision brake

> Accident situations in which the multi-collision brake enters into effect:

»

The multi-collision brake can prevent the rammed vehicle from being shunted
into the oncoming lane.

21

AUDI AG

INS

Presentation title

Date

Multi-collision brake