Replacing bench seat mounting studs

Dicer said
I would stick a piece of pipe in a vise upright, put the head of the stud into the pipe drive it on through. Use a bolt of your choice and tack weld in place. If you wish take your bolt stick in a drill and a nice bench grinder to the hexagon head....round, and tack, there you go.

Exactly!

I did the same with stripped studs in my bucket seat tracks. Popped them out, put these in, fits square hole same as the originals, Tack welded them in place, Worked great!

Get these at Fastenal, very cheap!