The lock pin is supposed to fall into the blind hole as it's driven in. It looks like the pivot pin is 90 degrees out of position, but you have no way to figure out which way the shaft needs to turn. Try a little heat on the case to expand the hole, and move the pin a quarter turn with a big screwdriver and vise grips, or a ground down drag link socket. You'll either line up the hole or need to turn the pin another 180 degrees. That pin is hard enough to need a solid carbide drill bit to hope to cut it.
Jerry
Hey Jerry ! The slot appears to be parallel to the pin and looks to be the the exact same orientation to the "spare" SM420 I have in the shop. I noticed the top of the pin was mushroomed over so that makes me think someone "whaled" on it to get it installed. The top of the pin on the "spare" is nice and flat/square/crisp.
I'm going to try the heat method first and drilling last.
