97 Legacy GT...... Brake issue

I have a 97 Legacy GT and every time I go in reverse with my steering wheel cranked all the way left or right (like leaving a parking space), I get an aweful grinding noise coming from the front right rotor/brakes. I havent pulled the wheel yet, but im just wondering what i should look for first. i can change pads and turn rotors, but this boggles me as it only does it in reverse with wheel turned. If i back straight out, no grinding??? Weird!

I figured it out. On the rotor heat shield behind the rotor, there are 3 bolts that hold it on. One of these bolts backed its way out and was scraping the rotor in reverse only. I replaced the rotor, put on new pads and am happy to report everything (brake wise) is ok!