I'm not been able to resolve this issue and am at a bit of a dead end. I have a Phaeton W12. When I brake there is a slight shudder at most speeds unless I brake fairly hard, except when traveling at 120 km/h and 85km/h, at these speeds the shudder is severe uless I brake hard, but this could be that the car slows out of these 'bad speeds' quickly. The shudder is unnerving and severe enough to expect that it will cause damage. I did have the disks/rotors skimmed on a lathe, I thought this had fixed the problem, I can't be sure it didn't. All seemded fine initially, but I don't remember the speeds I was doing when I tested the skimmed disks for the first time.
To add to the fun, I brought with me when I moved countries and VW won't work on it before its registered locally and I need the brakes to be working to do so. Chicken and egg sort of problem. Parst are also not freely available here.
There is a rubber suspension bush in front which I noticed needs to be replaced, which I will order today, but it's likely to take a few weeks to get here unless it's used on an Audi or another car sold here, but it's the opposite front wheel which appears to have uneven wear on the disk.
Can anyone suggest what to do?