1985 Buick Lesabre

Jack up the back end take off the tires and then try to turn the drum, it should turn freely, if not you will have ot disable the parking brake and turn the starwheel adjuster on the drum to retract the brakes, once it moves freely, spray penetrating oil around the center of the drums and the lugs that way it loosens up the rust, you may have to use a torch and a hammer to get it off, or it might just fall off.

Once you got both sides off, tear one down and reassemble looking at the other side as a map, to have a visual guide.