I picked up the Advance Auto radiator suggested to me on here (3 row) and I tore down my driver's side rear drum and cleaned all the parts. I think my adjuster screw/pivot nut is seized.
OK. Called NAPA and ordered both pivot nut/adjuster assemblies (both sides) and had them set me a set of brake drum springs aside as well. Gosh I hope I can get this all back together!