Originally Posted by Jeromee
It could be the backing plates on the rear brakes, they tend do to it with age. rust builds up behind them and pushes them out into the rotor.
Yeah, an independent Subaru mechanic, passed that along to me after I did my brakes myself. They always grind off a little of the corrosion back there, since the tolerances are pretty tight. After a bit of aggressive cornering I made the noise go away.