I found two cracks/breaks in the frame, at the rear. The passenger side is worse. It looks like it may have been caused by too much stress on the receiver hitch. The driver side, looks like it was stress from the rear spring hanger. I am wanting to replace the rear hangers with flip shackles. How do we repair the cracks? Will they be strong enough? Once they are fixed (welded or what ever, can i go ahead and put the flip shackles on? Should I reenforce the back sides with something to distribute the stress more?