Power steering bracket fasteners

Has anybody had this problem. 1970 maverick - There a 2 threaded anchors in the frame that secure the 3/8" bolts for the power steering cylinder bracket. They look like some type of snap-in anchors. I had one pull out of the frame. Just the threaded nut piece fell out, the other half of the anchor assembly is still stuck in the frame. How do I fix this?
By searching the web a bit, I found out they are called rivet nuts. how do they work though, do they expand when you tighten them up?

 

You use a special tool to insert them, it's kinda like a threaded rivet. Years ago I pulled them out on my 74, i drilled them out, and welded nuts in their place.

 

Thanks for the reply. I just came across this on a google search. I'm going to give it a try before I break out the welder. http://www.carolinarovers.info/croc-stuff/tips/259-make-your-own-rivnut-tool Let me know what you think.

 

http://www.stangerssite.com/framebrackets.html

Check this out! This is how i'm doing mine.

 

Excellent information, thanks for sharing that. I feel more confident now about getting this straightened out.