When this happened to mine I cut open the outside of the frame, then welded the cracks from the inside, added some extra re-enforcment, and then recapped it. I also plated the outside of the frame with 1/8 inch steel. Then I drilled the three bolt holes out to 1/2 inch and Installed grade 8 bolts through the plating. So far its holding up great! Zig I will e-mail a pic to you.
Mike