I looked in the archives....found nothing...so:

My wife's '98 S70 develops severe chatter in the front brakes when they get hot, it's hot out, and are used on hills. It's a "buzz" chatter, not an oscillation or cyclical pattern. Once it starts, it happens on the flats, going up hill, etc, until the brakes cool. Dealer replaced front pads and discs, blued from heat (claimed to be my cost), and replaced the back brake set (warranty) as they were not functioning right (no wonder the fronts were blued!!) Did not solve the problem. Then he said it's a tire pressure problem, pointed out that the tires we over filled (thanks, Costco)and proclaimed the problem fixed. Wrong.

Anybody have any info on chattering brakes for this vehicle, caused by heat load? I'm heading back to the dealer, again, and would like to have some ideas.