Ok this is a weird one...I installed new Axxis Pads on all 4 wheels a week ago...I measured the rotors and they were within spec so I didn't replace them...drove on them all week and were fine. Friday night it rains so the rotors get a little coating of rust, like usual, however, half of it has not gone away on the FRONT wheels! But no noticible loss of braking power, no shimmining, and just a slight bit of squeeling once in a while. Any ideas?