Quick question; I've had a 406 Brembo + Tarox G88 288mm+ EBC Greenstuff combo for about two years now but every few months they start to vibrate, probably due to stuff residue on the rotors. I've bought a new set of G88's; this helped but same problem within a few months. Had the old ones machined (just a small amount taken off), this worked great again for a few months. Machined the other set and swapped again; same problem.
Any clues as how to prevent this or fix it myself? I tried hosing them down with a pressure washer but that didn't help (much).
I've read about anti vibration shims, what are they, how I know if I have them or not and where can I get them?
Any help would be greatly appreciated as I have a track day coming up and would like to be able to brake in a straight line.