I know the best way to repair these pans is to pull it and weld a nut on the inside. What in the world was the manufacturer thinking when they didn't? As an engineer myself, that kind of poor engineering really chaps me. Anyway, I tried many things to no avail. Yesterday I installed a rubber O-ring that just fit around a x1 oversize plug, and I was able to get enough torque. Not a drop is leaking now.