If the vehicle has been sitting for awhile the rear brake shoes are rusted to the drums. I have been able to get them free most of the time by hitting the back of the drum with a good size hammer. This is for Caravans with rear drum brakes. For vehicles with rear disc brakes the hand brake shoes can cause the same problem,but you then have to remove the rear calipers, pads and rotors, and then sand off rust build up on surface where hand brake shoes ride. You may have to pound on face of rotor where wheel studs are to get rotor off be careful not to hit studs with hammer. An air chisel with a hammer head works good for this.
2003 Dodge Caravan Emergency Brake. The Pedal Released But The Car Doesn't Want To Move.What's Wrong?
Check the parking brake cables to see if they are seized-lift the rear of the vehicle and see if the rear wheels spin freely-you may have to remove the wheels and drums to see if anything is broken inside the drum or not