C4vettrn

Had this same issue before. couple ways mentioned will work but if your OCD like myself I will try to explain what I did. Get a flanged nut of appropriate size. Measure the size of flange or overall diameter and use one step bigger drill bit to drill your frame hole (where nut was welded originally). Your new nut should be a perfect fit in frame hole (flange facing down). Best way to insert nut is to stick on a magnet and the magnet will keep in place to tack weld and keep the nuts flange flush with frame. Tack nut in place remove magnet and weld circumference. Almost done, take die-grinder and grind weld flush enough it allows your cross bar to set flush. Hope that makes sense

Another way would be to weld a nut to the back of a fender washer then weld washer to frame (nut in hole). This would require using washers of same thickness between the frame and cross bar for the other mounting locations to keep spacing the same.

award78

You guys and your welders, lol. I am a little OCD but also a little lazy, bad combo. So I just used the serrated flange nut, which I was able to get good torque on. Hopefully it will hold for a while.
Thank you all for your help.

Car Analogy

This should work fine, until some mechanic works on your car, and will just leave this bolt off and toss it when there isn't a threaded insert there waiting for it to be threaded into.