Ok, salvaged this neglected Morgan Milwaukee 60 bench vise today, and may need a little help getting it back into shape. Here's how it looked when I got it home:
Disassembled, with a Snap On F80 for size reference...
I started posting before you were finished... Heres a good picture for general parts names. Every vise is built a little different but for the most part the same.
The main nut should be stationary held in place with screw, bolt or pin. The Jaws May lessen up with the electrolysis bath like I posted. After that some penetrating oil and a hand impact driver will help.