If not done already:
THREE ways: 1. As John says bang the drum but don't hit the drum/s with the hammer remove the wheel place axle stand under of course the axle then hold a block of hard wood on the drum and hit the hard wood.
2. Need thick gloves. Prepare drum for removal [it may have a screw in the face] if not it's the wheel nuts that hold it on. Warm up the drums with a blow lamp lightly tap the drum with the hammer,ok I did say don't hit the drum with the hammer but light taps are ok. The drum will slightly expand enabling the drum to be removed, It works I've done that on a car as well.
3. If yours has the new braking system which 'Lock OFF' on reversing enabling reversing on to a pitch easy then if you have the room behind the c/van hitch up and reverse it may kick the brakes off. Clean up the brakes if they don't fully release. If you remove the break shoes then take a digital picture first so you know what goes where.
Nobby
April 2008