Now we're getting to the fun stuff.
1.Cut the pin in the middle and then wedge a screwdriver in the cut--that should give you enough grunt to get the one piece to back out of its hole. If it doesn't back out, drive it in with a drift to loosen it up
2. Once the first piece is out, grab the end of the remaining piece with your vice grips and try a bit of bending and turning to break it loose.
3. If 1 & 2 don't work just grind the pin off flush with a dremel.
4. In any case drill a new hole at 90 degrees to the original all the way through the casting and fit a new pin that can be driven out from either end (better design).
Drilling a steel
pin out of an aluminum
casting is really hard to do. Using a drill bit as a drift punch is risky, as they tend to break off and leave you with an even harder pin to remove.