I wanted to change rear drum brake shoes today. After I removed the wheel, I noticed a retaining screw to the drum. One was missing. There was only one screw. It was stuck. I sprayed PB blaster, torched, but nothing worked. The screw head was partially rounded. How can I remove it? I don't think it is much important as the ones in the front rotor, but I need to remove it anyway in order to remove the brake drum. Is it possible to cut it off? Any advice would be greatly appreciated.