APPROACHING INTERSECTION STOP LIGHT, TRIED TO APPLIED THE BRAKES AND THE PEDAL WENT TO THE FLOOR NO BRAKES AFTER SEVERAL ATTEMPTS. WAS FORCED TO USE THE EMERGENCY BRAKE TO STOP BUT STILL HAD COLLISION WITH ANOTHER VEHICLE. AFTER THE DEALERSHIP REVIEWED THE BRAKES IT WAS DETERMINED THAT THE RIGHT FRONT BRAKE CALIPER MOUNTING BOLT WAS MISSING WHICH ALLOWED THE CALIPER TO ROTATE OFF OF THE ROTOR AND CLEAR THE PISTON FROM THE ROTOR SURFACE AND THEN THE PISTON WAS FORCED OUT OF THE CYLINDER AND LOSS OF BRAKE FLUID RESULTED.