Horizontal Stab. rusted on stubs

I'm taking apart the tailfeathers of a Tcraft. Elevator came of fine.
The two halves of the horizontal stabalizor slip over a fore and aft
piece of tubing that is welded to the fuselage. The Cub does the same.
The leading edge connection came apart without problem, but the
trailing connection is rusted tight.
I've done everything I can think of except for heat (fabric is still
on). PB Blaster, tapping, screaming.

I"m open to suggestions if you got 'em. - Mike