Hi Phil,
A couple of ideas...Try PD Blaster as a solvent. I removed every one of the screws from my 1985 Nissan PU's exhaust manifold's heat covers. Many of these were very rusted after 18 years. I sprayed them all down a couple times and let them sit for a few hours. Every one screwed right out...no breakoffs or tight ones. Can buy at Wally-World for approx $4.00 a can. BEST stuff I have ever used. Comes out in an orange foam.
Next, sometimes, one can make use of a dremel tool to make a slot for a screwdriver blade or repair a bolt enough for a socket again. Yours may be beyond that....
Your internet handle interests me. Did or do you work for Unisys Corporation? Just curious...
Good Luck, Duane in KC
