[ainarssems]

I have not had any issues with them on 8 so far but I had 3 of them fail on A6 1 shortly after another, first it was intermittent but gradually got worse. I don't think they are the same on 6 and 8 but very similar. I took them off to investigate and found that because they are sealed units they had a lot of carbon dust build up in side from the wear of carbon brushes. The brushes and slip rings were still in good condition, it's just that all the wear dust was either shorting out or preventing good connection. I cleaned them up, greased bearings and gears with fresh grease and re-assembled, worked as new since without any problems. So if they are £120 each new it might be worth checking to see if the old ones are serviceable. Or if you buy second hand it could be a good idea to give them overhaul before putting in the car.