Seriously dumb question about frozen/rusted brakes

Power divider (and diff locks if you have them) locked?

 

I think the easiest thing to do at this point is to get the tooling to pull the wheels, back off the brake and give the drum a couple good whacks with a sledge. Just be aware that it is possible to split the drum in half doing that. (Been there, done that lol).

 

I concur, get under it with a hammer.
Charge the brake system, (release the brakes), might have to remove the inspection covers, then hit the rim on the back of the drum as straight on as you can with a hammer at different points around the diameter.
Use a good sized hammer that you can swing freely with one hand so you can hammer near the top of the drum.
Try not to hit the the drum at an angle or on the side, tapping might be okay.

Here's hoping they pop for ya, fingers crossed.

 

I carried a dual-purpose bar, it was steel, about one inch diameter and about two feet long. It was for both the winches on a lo-pro step deck (especially with wide loads) and for unfreezing drums (again, especially on lo-pro step decks) by using through the wheel holes and hitting the end with a 5 lb sledge. Worked great for both.

I suppose a third use would be knotting heads, but I never got to test that.

 

Kinda on topic but what causes brakes to jam up like that? I remember it happened once on an old pole trailer my dad bought. Couple whacks on drum with a sledge freed it up. Other than that we'd only see the odd wheel freeze up after a truck wash in winter. Just a little bit of torque in reverse or just the weight of the truck trying to roll down the driveway was enough to break them free.

 

You're in uncharted territory for me. I have not ever not been able to break a wheel free with all 4 locked up.

If the drum is worn and there is a ridge on the open side of the drum the brakes still need to be released before the drum will come off.