[Chevy Fleetside]

It took me a while to figure out the picture. Looked like the hub was rusted but after looking, it seems that is part of the drum that is rusted onto the hub. If you remove the hub you should be able to press the studs out and get that apart or the part is just junk and might need to find another hub which would probably be a lot easier.

You could also remove the hub and soak it in penetrating oil for a few days. More then likely it can't be save but you will never know unless you try.