Broken K frame bolt 74 Swinger
Looks like the attempt put the drilled hole off-center. I'd drop the K and weld a nut to what's left, giving a place to use a socket. The heat should help with spinning it out. Then asses the thread damage. Maybe just a chase and your good to go.
I mean no insult to the OP when I state that this is CLEARLY above his skill level.
OP: drill a 1/8" hole GENTLY above each of the remaining 3 bolts, and spray a good penetrating oil on them before you remove them. This will allow you to spray the threaded portion of the bolt. DON'T drill the bolts.
As for the broken one: remove anything you've broken off in the hole. This is step one.
Then you're going to either take it to a shop and pay dearly, or find someone with a cutoff wheel and a welder, and they're going to cut a side plate out of the frame rail, spray the bolt with penetrant, grab the bolt sticking through the nut, and break it loose, and thread it through (as in, up into the frame rail).
Then weld the frame rail section back in. Mig or Tig only. No stick, and no flux-core BS.
And use anti-seize on the bolts when you put them back in. If you've gotten off-center a little and nibbled the threads you'll probably be OK, but use a torque wrench instead of an impact gun.
