M5 Halftrack: stuck on front brake drum

[motto (RIP)]

Assuming the brake setup is similar in design to White Scout Car, Dodge WC and Jeep in having major and minor adjustments that would be a good starting place. The minor (upper) adjustment is a simple snail cam that merely restricts how far the shoe can move away from the drum. Rotate the adjuster in one direction and it will have a soft take up as the cam surface contacts the shoe, go the other way and it should come to a dead stop as the tail of the cam contacts the shoe. Move it just out of contact and it should be well clear and play no further part.
You could try hammering around the drum at this point with a sledge hammer and a block of wood. The ends of the shoes should be sitting against the wheel cylinder pistons and you will be trying to jar them into giving a little clearance.
If no good then loosen the lock nuts on the major (lower) adjusters. These are eccentrics and will drive the lower ends of the shoes in an arc. You should be able to rotate them until you find the loose point.
If none of this works then proceed as Lynn suggests and the shoes should come off with the drum.
Good luck.

David

Thinking some more on the matter Gina there may be an additional attachment point for the shoes to the backing plate that will interfere with their coming off with the drum if you attempt to do that. The attach points act as guides and take various forms depending on the vehicle.