I finally decided to tackle the cracked subframe on my 73 swinger. I cut out the bad metal on the bottom where the rear kmember nut is and removed the nut. I ended up internally sleeving it with a piece of 3 by 2 inch 3/16th wall steel tubing. I did 3 3/8ths plug welds on the inner side and 5 on the outer side. Drilled the ends of the cracks and beveled them with a carbide bit in my die grinder. Then welded it all up and ground it smooth. This seemed more daunting than it actually is.

If anyone ever needs to do this, I took some pictures that may help show what I did. Make sure to measure 500 times and cut once!

 

Thanks brother! It's been on my to-do list for way to long.

 

Thank I really appreciate that. Frame work has always kind of freaked me out. I just grabbed the bull by the horns and did went for it. Turned out way better than I would have hoped for. I really learned that if I can do it, anyone with a welder and time could do it!

 

3x2 3/16th wall. Went and measured and corrected my post!

 

Thanks buddy!!!

 

Yes it's the same piece, I was test fitting it, and then marking where I needed to drill the hole for the kmember nut. And absolutely, I always drill the starts and ends of stress cracks, all it actually does is prevent it from spreading during the welding process. Added bonus is they are additional plug welds! The rear of the tube extends into the frame about an additional 1/2 an inch too, so even if the cracks come back, it will still be safe. Nothing can move!