only pads were changed. Changed at 38,000 miles. All four rotors had been changed at about 15,000 for a complaint that I had. Now, the car shimmies if breaking hard from a high speed, >60 mph. Is this the pads being broke in or are my rotors slightly warped?? <p>Dealer has been very friendly with me (ie bubbled tires, bent wheels, etc) but should I make an issue about this?<p>Should the pads and rotors be changed at the same time every time??<p>Any comments would be appreciated.