Not much time for Jeep tinkering, but I did a little yesterday. I got a thought while traveling over weekend -> Maybe I could use a piece of 1" square tubing to make the replacement for "M" piece. (It will now be a "U" like atHawk's) It will also extend all the way to the bottom of hole, (because the more I look at passenger side, I am convinced my original did extend down, but has rusted away.
Maybe finally making some progress. The bracket is going to be 3X stronger than the other side (thicker steel, and much less rust). I am debating removing the other, putting in a replacement "U", and patching the bottom of hole (the wheel housing is rusted thru, the bottom of hole is actually that reinforcing plate.) I did not notice that from the outside, but can see if looking closely from the top. . . . Oh wait, I was thinking I was making progress, that would be going backwards. . . Oh well, the life of fixing a rust bucket.
I also narrowed the front piece of bracket. I had to grind the radius thin, hammer it narrower, then weld the inside of corner back to original thickness. (red arrow in photo below)
The pieces mocked up for photo, I hope to get some time tonite to weld it up!