Good advice. I used a high-speed wire wheel to remove paint, rust, etc. and get down to bare metal. Between that and a feeler gauge I was able to locate and drill out the spot welds. After working at it for a couple of hours, I successfully removed the driver-side outer corner.

My next dilemma is the fit-up of the new patch panel. Not good. It appears I'll have to cut off part of the inner cab corner to make it fit, or buy a different cab corner. Grrrrr! Have others had this problem?? I noticed the sticker on the patch panel says "made in Taiwan".

I'm curious to know how others have welded in the new corners? Two thoughts come to mind: I could use a continuous butt weld, or maybe a flange crimping tool along the seam and then a lap weld where the two edges overlap. Thoughts?