No "U" channel at any auto parts store; at least none that I could find
Plan "B" went to Lowes and found 1/4 inch extruded aluminum. Only need a 10 inch piece. Removed the Old, Rusted Channel from the solid mounting Bracket. Pop riveted the new channel to the old bracket. Added 3M red double sided tape to both insides of the U. Ready to bolt back on.
I have decided to remove the glass from the door to install new piece.
Does anybody have any experience replacing lowering door glass?