1999 Audi A6 2.8l Quattro wagon front rotor size
 

So I need to order some new front brakes for my 1999 Audi A6 2.8L Quattro wagon. I took it in to get the rear brakes replaced last year and this year the front brakes are finally starting to wear out. They are the original breaks so they are pretty old. The only problem is I don't know what size rotors it needs. 288mm or 312mm?

Highest probability is the 288mm, but i'm not sure if the Avant was different than the sedan. Just measure it, it's just a few lug nuts.

My 2001 Avant has 312mm. I can't confirm for 1999 though... 2 ways to be sure... 1) take the wheel off and measure. 2) call the dealer and see if they can give you the info based on the VIN. One is probably easier.

1999 Audi A6 2.8l Quattro wagon front rotor size
 

They both work. 288 is the original size and 312 is the largest you can go on the front. Just installed new PowerStop 312 rotors on the front of my 2000 quattro avant 2.8. Big difference.