I replied to your email explaining what's happening and how to repair it with Rodney Dickman's cradle nut replacement part.
http://rodneydickman.com/product_info.php?products_id=304This was a relatively easy fix on my 86. The picture in this link for another repair kit he makes shows how the hole is cut into the side of the frame rail for installation. For the money and ease of installation, the link above is the way to go. No welding is needed with it.
http://rodneydickman.com/product_info.php?products_id=276For others who might encounter the same problem, this is what I wrote to Allen.
There is a floating nut inside that the cradle bolt goes into. Rodney Dickman makes a replacement, but you have to cut a hole in the outside of the frame rail in order to install it. Just be sure that you don't cut the hole all the way down to the lower edge of the frame rail. It's best to drill a hole at each corner of where you intend to cut, then between the holes and upward to make the flap. I'd leave about 1/8 inch of the side along the lower edge. I had to do that on my 86.
http://rodneydickman.com/product_info.php?products_id=304The original nut that's inside has a shoulder on it. I think it's on a metal plate that has several tabs that fit loosely over the shoulder of the nut so the nut has a little movement for alignment purposes. In my case, the nut had turned loose inside and was spinning. You may have to drive upward on the end of that bolt and break the nut loose if you can't get the remainder of the bolt out. You can remove the remnants through the window you cut in the side.
When we installed my replacement pieces, we didn't weld them in. The plates shown are long enough that they won't make a full rotation inside the frame so you can tighten the cradle bolt. Once the front bolts are in place and the cradle is swung upward to install the rear bolts, you can hold the replacement nuts with a wrench or fingers inserted through the side of the rail until the bolt is snugged down.
Neither did we weld the flaps shut again. We just bent them back down to close up the hole. We made sure to put lots of anti-seize on the bolts should the cradle ever need to be dropped again.