S8 Braking problems - help!
 

hi everyone1
got a proper problem - my baby is diving around and shuddering when braking despite new front and rear tyres and discs/pads - Audi say they can't replicate the prob, it happens when I am braking down from 50ish thru to 40ish, get an ABS-type judder on the pedal and steering wheel shudders! no warning lights and this is in dry daylight conditions!
it's been suggested it may be the ABS rings and also the hub, don't want to spend much more trying to find out! anyone had similar please - she is a 52 4.2 auto with 69k
cheers in hope!!
Joanne

Will it stop if you brake hard? Does it stop below 40? Does it happen from cold or only when you have braked a few times and warmed them up? I would suspect a sticking calliper or dirty ABS sensor. Probably dirty ABS sensor that is actuating at that speed. Get both the front sensors out, give them a good clean and see if that cures it. +++

Hey there, thank you very much for the speedy reply and suggestions!!
Ok, so she's usually well warmed up when it happens, and am not confident she actually would stop properly, what I do is try to let her gear down a bit then tap brakes again, have been leaving extra room from the cars in front just in case! Yes it seems to stop below 40.Audi said all calipers are free, yet I felt that she was being "held back" almost when the recent few occurrences happened, and she almost seemed to want to stall? Mystified and a little nervous, as you well know she's a lot of car to stop!!
thanks!!

Find a bit of clear road get up to 50 start to brake and if you get the symptoms brake hard enough to cause the ABS to work. If the wheel wobble stops but the ABS works properly that would indicate the problem is with one ABS sensor. As soon as the other sensor activates the judder balances out.

You say it feels like its being held back makes me think of sticking calliper again but my gut says ABS sensor dirty or malfunctioning. Any other forum members near you? Have you read the codes from VagCom?

Hi Conan,
Thanks again and I will do as u advise asap - heading to work in Stockton makes it almost impossible for an empty stretch at 7.30am but will have a go, not scared to try the ABS, and have just remembered that Shane in Sunderland replaced a sensor about 18mths ago for me, so perhaps it's the other one or dirt as u suggest. am sorry but not sure about Vagcom, am not a very good user of your site as I never have time to learn all the terms, I only pester you when I have a problem!!

Hmmmm didn't know my wife had bought an S8 and moved ooop north! :ROFL:

yes teehee, am but a simple woman driver, clueless - well actually not that bad but have now checked out VAGcom, what a clever set of tools!! when i handed back the brand spanking new A6 2.TDi at Audi today and collected my honey, they did say they would check in with me tomorrow if the problem happened after I drove home, so will inform them and mention your advice etc, see if they offer to look again for me - they seemed keen to have it resolved - recall it wasn't expensive when Shane put the first sensor in. i do a lot of miles so easily poss for dirty sensors i guess!
very grateful inded for your time and wisdom, will update u on progress if that's ok??
cheers
JoJo