Also depending on wear your rear drums might have a lip on them where the brake shoes have worn into to the drum. If so you may need to back the adjuster off an 1/8inch to retract the shoes a bit. If the lip is big when you get them off also look at the shoes, if they are worn then slap on a new pair and either have the drums turned or pickup a new set... I also always use new hardware when doing this if the stuff thats in there is rusted badly, especially the adjuster...
Almost forgot, if they have never been off they may still have those retainers on the studs, I just cut them off with a pair of dykes, dikes, sidecutters...