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cbhoyer
06-11-2016, 02:06 PM
Hi,
Hope someone can help me to identify a rather annoying sound from my brakes - as my Audi dealer cannot :-(


It is an A3 Sportback Ambition 1.6 TDI 110 hp, automatic transmission, bought new from factory October '15, now app. 14.000 km.


It's hard to describe the sound, but it kind of reminds me of Chewbaka from Starswars having a cold ;-)


I have put some recordings in Dropbox:


Dropbox - Brakes-1.mp3 (https://www.dropbox.com/s/3qvg27p4cr7fbeu/Brakes-1.mp3?dl=0)
Dropbox - Brakes-2.mp3 (https://www.dropbox.com/s/dqts7yps4aug2t6/Brakes-2.mp3?dl=0)
Dropbox - Brakes-3.mp3 (https://www.dropbox.com/s/ryyxf2byxiblwtz/Brakes-3.mp3?dl=0)
Dropbox - Brakes-4.mp3 (https://www.dropbox.com/s/o0ntol5ei8kw0an/Brakes-4.mp3?dl=0)
Dropbox - Brakes-5.mp3 (https://www.dropbox.com/s/u8d13x90li0ji9i/Brakes-5.mp3?dl=0)
Dropbox - Brakes-6.mp3 (https://www.dropbox.com/s/gi0vdn3qjqr53oa/Brakes-6.mp3?dl=0)
Dropbox - Brakes-7.mp3 (https://www.dropbox.com/s/hkuzlpigqdf04g6/Brakes-7.mp3?dl=0)
Dropbox - Brakes-8.mp3 (https://www.dropbox.com/s/2zb85bcmcph6on4/Brakes-8.mp3?dl=0)


It is an intermittent fault and it's not been possible for me to identify specific conditions under which it occurs, only some general characteristics:


The sound appears when maneuvering the car after parking - the first 10-20-30 meters, but then disappears and both when driving forwards and backwards (however more frequently when driving backwards).


It's partly related to weather conditions (lower temperature, higher humidity and rainfall/snow). Most frequently I've experienced it in winter conditions (below freezing point, but never below -10 Celsius/14 Fahrenheit) or during rainfall, but also when above freezing point (+5-7 Celsius/44-50 Fahrenheit) and dry weather.


The sound is not related to parking for lengthy periods, e.g. I have experienced several times that it is present even though the car has only been parked for a few hours (and that after after driving at least 20-30 km/12-18 miles and definitely having "clean" brakes).


Several times I've experienced a pattern with the sound appearing when leaving home, driving 20-30 km and after parking ½-1 hour it's there again, completely the same sound, that disappears after maneuvering. After parking in ½-1-1½ hours is the same pattern.


The sound is of a completely different character than the ordinary "squeaking sound" you hear when maneuvering a car with automatic transmission.


My Audi dealer has tried several explanations, including that it is related to the rust can be seen on the discs in wet weather, when a car has been parked for some time - however, the discs have always been "clean" - and the sound is not the same as the one you can hear, when the discs are in fact rusty after parking for a while.


I've read about pebbles getting stuck in the brakes, but it seems unlikely to me, that I would get pebbles in the brakes so frequently as well as I'm mostly driving ordinary paved road in the city - not offroad in any way.


A mechanic at Audi said that "they had experienced this before" on exactly this model, but could not give further explanation - which also puzzles me a bit if it's something as "trivial" as pebles in the brake.


Looking forward to suggestions - it's really annoying - and the Audi Dealer tries to fob me off with "that's just the way it is, get used to it..."

wibblyw
10-11-2016, 09:58 AM
Long shot - I once had a car that made the most peculiar noises seemingly under odd conditions. Turned out to be a tyre hitting a mudflap that had become dislodged. Maybe try checking for something like loose trim in a wheel arch dropping down/moving to touch a wheel....

cbhoyer
12-11-2016, 01:07 PM
Thanks for your suggestion.
It's definitely not something like that - there's noting to see like that - actually that's part of the problem - if only something was there - only the sound is there (and of cause not when in the Audi workshop...).

Has anybody, no matter if they have an explanation or not, heard this sound before?
The boss at the dealer said, that this type of sound had he heard before - but I haven't really met anybody else who has...