mishar

Check the sway bar U links.

jakematic

Hmmmm.

Mine has been doing the same thing and I've always read it was attributed to bushings.
Glad it hasn't been rushed into a mechanic....

MP4.2+6.0

Before a lot more "what ifs," look at the upper front control arm inner bushings. It is the one obvious part of the front suspension that is universally known to wear, and for which Audi has issued a service bulletin specific to the D3. Would also explain shaking under braking if they are well worn (BTDT on my A6 4.2), as well as knocking out alignment (as long as the old ones are in there) and then the tire wear. Someone needs to just shine a flashlight up in there at the upper inner bushings and look. Been posted many times before if you need more info/background.

On lower arms, I definitely would not be changing those without looking closely at uppers first, especially again the front one. The lower arms are also designed to move laterally some--not shake loose of course, but shift some as the steering moves. If you move the wheel lock to lock you can see it.

BigladUK

Thanks to everyone for posting, it's been a real help.

What I do know is that the Rotors and Discs were both replace at the front in Sept 2011 and 2 different garages have confirmed these are fine. One garage has said the lower suspension arms need replacing ( which I think is rubbish ). Another garage said all the bushes are fine and the problem could be related to the balancing of a wheel or maybe alignment.

So my car is booked in on Monday to an Audi Dealer for proper diagnosis ( i'm going to have to trust someone I guess )

The one thing I hadn't mentioned, which all now seems to tie up given the post above me and what some of the other posts have said, is that I got an advisory in September 2011 when the car was MOT'd, that the upper front control bushes were worn but not causing excessive play. So given I trust this to be true and the second garage I went to said none of my bushes were warn I assume my upper front control arm bushes ARE now warn and I'm suffering excess play.

It kind of all makes sense now even down to the excessive tyre wear.

So, if there is a service bulletin for this for the D3, will Audi sort this FOC ? How do I reference the service bulletin with my UK audi dealer

Si

Edd W

Brake disks very rarely warp, judder under braking is almost always caused by an uneven coating on the surface of the disk.

As you brake a small amount of the carbon created as the friction material meets the iron of the disk, chemically bonds to the iron molecules creating a coating on the friction surface. If this coating becomes uneven for some reason, usually rust or parking the car when the disks are very hot, this causes a variation in the coating which causes a judder as the pads hits the area where there is less friction.

There are many technical articles on the subject which go into far more detail and more accurately than I have here but I too thought warping was the cause until a few years ago when I could not understand why I had a brake judder, when a dial gauge on the surface of the disk showed minimal run-out.

From Wkipedia article - 'Often uneven pad transfer is confused for disc warping.[citation needed] In reality, the majority of brake discs which are diagnosed as "warped" are actually simply the product of uneven transfer of pad material. Uneven pad transfer will often lead to a thickness variation of the disc. When the thicker section of the disc passes between the pads, the pads will move apart and the brake pedal will raise slightly; this is pedal pulsation. The thickness variation can be felt by the driver when it is approximately 0.17 mm or greater (on automobile discs).'

http://en.wikipedia.org/wiki/Disc_brake

Edd W

Not very local to you but may be worth giving these guys a call -
http://www.thevwaudispecialists.co.uk/index.html

BigladUK

I'm pretty confident it's not the brakes as
They've been checked by 2 different garages
They are only a few months old
I won't feel any vibration/feedback via the brake peddle

I'll ask Audi to check them though but I'm confident it's the upper front bushes that are at fault

Si

MP4.2+6.0

Audi Technical Service Bulletin 40-08-07, issued October 29, 2008. Clacking noise from front upper suspension or bushings torn (D3). It superseded 40-08-01 if they happen to find that one, due only to a technicality in the numbering.

Not sure how these bulletins work in other countries, but of course U.S. dealers have them. I have come across a few in German over the years too, so I expect they exist across countries in some form.

Baloo588

I have vibration on braking on my 2006 A8L with 166k miles and had the brakes and rotors replaced few months back. I was complaining of small speed related vibration on highways before and found out that the 4 upper control arm bushings needs to be replaced. They are the same ones that are causing vibration of steering wheel on braking so I ruled out brakes/rotors now and will get them done next month. This is the first time I have ever had bushings go for me as the car is very high mileage and even causing vibration on braking. You learn alot over the years...

BigladUK

Sorry guys, ment to post back here with an update.

Took the car in to my Audi Dealer and the did a full check for me ( for free including wash and valet :-) )

They concluded that I had warped discs front and rear plus my rear tyres were misshaped.

I took the car to the place I got the new discs and pads fitted 9 months ago and they replaced them under warranty.

The car is fine now and all shaking has gone.

So my problem was warped front discs

Si