Technical product information
Topic
Market area
Brand
Transaction No.
Level
Status
Release date

Brake noise identification
Bentley: worldwide (2WBE),Hongkong-Macau (5HK)
Bentley
2052785/1
EH
Approval

New customer code
Object of complaint

Complaint type

Position

running gear -> brakes, brake control -> service brake noise, vibration -> noise

Vehicle data
New Continental GT
Sales types
Type MY Brand Designation Engine code Gearbox code Final drive code
3S3* 2018 E
*
*
*
3S3* 2019 E
*
*
*

Mulsanne
Sales types
Type
3Y2*
3Y2*
3Y2*
3Y2*
3Y2*
3Y2*
3Y2*
3Y2*
3Y2*
3Y6*
3Y6*
3Y6*

MY
2011
2012
2013
2014
2015
2016
2017
2018
2019
2017
2018
2019

Brand Designation Engine code Gearbox code
E
*
*
E
*
*
E
*
*
E
*
*
E
*
*
E
*
*
E
*
*
E
*
*
E
*
*
E
*
*
E
*
*
E
*
*

Final drive code
*
*
*
*
*
*
*
*
*
*
*
*

Bentayga
Sales types
Type MY Brand Designation Engine code Gearbox code Final drive code
4V1* 2017 E
4V1* 2018 E
4V1* 2019 E

*
*
*

*
*
*

*
*
*

Continental GT and Continental GTC
Sales types
Type
393*
393*
393*
393*
393*
393*
393*
394*

MY
2012
2013
2014
2015
2016
2017
2018
2012

Brand Designation Engine code Gearbox code
E
*
*
E
*
*
E
*
*
E
*
*
E
*
*
E
*
*
E
*
*
E
*
*

Final drive code
*
*
*
*
*
*
*
*

394*
394*
394*
394*
394*
394*

2013
2014
2015
2016
2017
2018

E
E
E
E
E
E

*
*
*
*
*
*

*
*
*
*
*
*

*
*
*
*
*
*

Flying Spur
Sales types
Type MY Brand Designation Engine code Gearbox code Final drive code
4W2*
4W2*
4W2*
4W2*
4W2*

2014
2015
2016
2017
2018

E
E
E
E
E

Documents
Document name
master.xml
brakenoisequestionnaire.xlsx
flowchart.docx

*
*
*
*
*

*
*
*
*
*

*
*
*
*
*

Technical product information
Brake noise identification

Customer statement / workshop findings
Customer statement:
Noise complaint from the braking system.
Workshop findings:
The noise can be reproduced and clearly assigned to the braking system.

Technical background
Brake noises can be attributed to many causes. Eight of the most common causes are:
1. Brake discs or pads are close to their wear limit.
2. New brake pads and/or discs have not been properly bedded in after installation.
3. Aftermarket pads or discs are installed.
4. There is debris such as small stones, grit, road salt or sand between the brake disc and pad.
5. Discs are covered in rust. Rust can form when the vehicle has been stationary for long periods of time (Figure 1).

Figure 1
6. Discs have a groove in them (Figure 2)

Transaction No.: 2052785/1

Figure 2
7. There is chemical contamination on the braking surface of the disc due to a wheel or tyre cleaner being sprayed directly onto the disc (Figure 3).

Figure 3
8. There are ‘pad marks’ on the brake disc as a result of the brake pad material transferring to the discs. This can occur when a vehicle has been stood
for long periods of time in a wet or snowy environment (Figure 4).

Figure 4

Production change
*

Measure
Note: For correct diagnosis and repair the attached Flowchart must be followed.
1. Check the overall condition of the brakes to determine if the brake noise can be attributed to one of the causes listed in the Technical Background
section of this TPI. If the noise is not a result of one these causes, proceed with point 2.
2. Record the noise and frequency
For the frequency analysis and the noise recording we recommend using the Chassis Ear Tool WT 10437.
To record the noise and measure the frequency using WT 10437 Chassis Ear Tool follow these instructions;
Refer to ‘File recording’ in the WT 10437 user instructions.

Using the microphone provided in the kit, record the noise from outside of the vehicle.
If the noise is only replicable during a road test, the microphone still needs to be positioned outside of the cabin for the best results. The assistance of a
second technician is required.

WARNING
Do NOT attempt to carry out the road test alone. The driver's concentration
MUST be focused on the road at ALL times.

WARNING
Observe usual road safety procedures and speed limits.
Select ‘FFT Graph’ as Wave Form Type and read the peak achieved during the recording as highlighted in the example above (in this case brake
squeal peak frequency is 2000Hz).
Save the file to your device.
The sound recording/video can also be taken from a mobile telephone as long as the noise is clearly identifiable.
If the noise cannot be reproduced a customer recording of the noise is also acceptable.
3. Check to see if a TPI is available that matches the customer complaint and recorded frequency. If there is an applicable TPI available, apply it and
complete a DISS complaint to include ‘Workshop findings’ only (No repair query required).

Should there be no applicable TPI, proceed with point 4.
4. Raise a DISS technical query. Both the completed ‘Brake noise questionnaire’ and the sound/video recording must be attached.

Warranty accounting instructions
Warranty claims about noise complaints caused by the brake system are only possible with a completed ‘Brake noise questionnaire’
and an audio/video recording.

Noise complaint from braking system

Visual check of braking system as per the Technical
Background section of the TPI

Not OK
OK

Follow standard repair
procedures then retest for
noise

OK
Use WT 10437 to create sound recording and
record frequency

TPI available?

Yes

No
Raise a DISS technical query
Attach the completed ‘Brake noise questionnaire’
Attach the sound/video recording

Noise still present
OK

Repair as per TPI then retest
for noise

Noise rectified

Noise
rectified
ddd

Noise still present

Vehicle is fixed

Brake noise questionnaire
Vehicle information:
VIN:

Road test:
carried out:

yes

complaint confirmed:

Noise type:

no

When does the noise occur:

grinding

judder

squealing

moaning

creaking

clonk

rattle

Where does the noise occur:
Front axle

yes

forward

backwards

always

slow down gently

Hold (e.g. at traffic lights)

0-30 k.p.h.

often

slow down hard

Curve

30-60 k.p.h.

rare

emergency stop

very rare

without brakes

more than 60 k.p.h.

Brake temperature:

Free Text:

Rear axle

cold

Frequency:
Noise recording or video must be attached to the DISS or sent to Product Support Inbox

kHz
How long has the noise been occuring:

Noise occurs only once in the same direction (repeatable moving back and forth):
yes

no

Does the noise only occur after the vehicle has been stood:
yes

no

If answered yes, how long was the vehicle stood for?

Does the noise still occur after the brakes are applied several times:
yes

no

Road conditions when the noise occurs:
Smooth surface

Rough surface

Cobblestone

Condition of the brake discs:
Okay

rusty

hotspot

Groove outside

Groove inside

Cracks

tinged

Sediments on the pad

Brake pad wear (visual check):
%

Front

%

Rear

Outside temperature:
of

15

C°

20

to

C°

Weather:
wet

dry

Snow

Customer Driving profile:
short haul

Long haul

sporty

normal

driven daily

not driven daily

parked outside

parked inside

other:

Further information:
(if necessary)

Repeat repair:
yes

Previous repair information:

no

hot