You may need to back the adjusters off. There's also a good chance that there's some rust buldup of the hub that's preventing the drum from comming off easily. Try giving the drum a shot of a good penetrant like B'Laster or Kroil around the hub pilot as well as each wheel stud hole. Let it soak, then rap the drum between the studs to break up any rust there. Then rap the drum around the outside diameter towards the wheel side (brass hammer preferred). The drum whould come free. You may need to give it some "persuasion" by adding some light to medium presure using a small prybar between the drum and backing plate, appying presure as you rap the drum.. Be gentle doing that, as you do not want to damage the backing plate. I have removed many drums with this method.
