Can someone suggest best way to fabricate bracket of some kind . When my truck was painted , they connected both sides with welded 1x1 tubing , cracked once at the weld , weeks later cracked on the other side , ...removed tubing and made different bracket from angled iron by different shop who does only welding ...week later cracked ( not at the welding thought ) .... I regret not getting special bracket for my suspension type ( trying to fix the way it is without ordering it and redrilling fenders )
I would weld a metal triangle where the horizontal piece and the vertical piece meet. Weld it on the front side to help support that stressed point. I can't tell how much room you have but you'll want to keep the brake chamber accessible.
That angle iron cross brace looks like a good idea but should be higher so it’s inline with bracket. The way it is now it puts stress on the area where it hangs below bracket . Least that’s what it seems judging by pictures.
I don’t know if anything is going to work. Your frame rails flex and move independently of each other. You could try welding triangle braces on, but I think they will crack the flat stock either up higher or crack the angle iron.
I would add two triangular gussets on either side of the cracked vertical to stop the flex from the weight of the fender hanging there and thicken the cracked vertical piece.
