The other day, me and a friend replaced the front brake pads on my 07' Taurus. Once we had them installed, we test drove it and everything was great for a little while. A day or two later, i start her up and pull into reverse and once i step on the brakes, it sounds as if there are two pieces of metal grinding on each other and the vibrations from that can be felt inside the cabin. Once i pulled into drive, i hit the brake again and i heard a little clank and the brakes returned to normal. This only happens whenever i pull into reverse so im really worried about this. Please note my rotors are possibly warped/need to be resurfaced or just replaced now after all of this. On another note, a week after all of this has happened, i cant go over a little bump without the front end sounding like its going to fall apart. That leads me to believe that my ball joints are out but i am not sure...