I'm having some problems replacing the magneto pinion on my ATD. How do you dismantle this? According to Know thy beast you just drift the main unit off the pinion/ring with a few blows with a soft drift. When I tried this I ended up with a bent ring and baseplate. I then drilled the heads off the rivets and managed to get the pinion and ring off but am now stuck with the rivets hanging from the baseplate....Help!