Brake Pad stuck after releasing Air Brake

Yes, beat on the backing plate with a ball peen hammer. You run a real risk of breaking something with all that torque. There was just a thread a few weeks ago about a guy who broke two teeth off of the ring gear doing this!

This is the easiest and saftest way. YOu can also take a big hammer and hit the edge of the drum to try and brake it free. Not my favorite way. If you can take it for a ride about once a month and apply the brakes a few times to get the rust off the drums will help also.

The usual reason for the problem is that it was parked with some moisture left in the drums as in after a rain shower, etc.

To prevent the sticking, although this is hard to remember to do at the time it happens, is to apply the brakes lightly as you park it. This is enough to heat up the drums and evaporate the moisture.

If you forget to do the above, as I have, rather than just putting it in gear and breaking it loose, try gently applying forward and reverse to break it loose.

Rocking is better than just trying to go in one direction.
I have had to move hundreds of semi trailers that had been stored for over a year or more.
Beating on the drum with brakes released is a bad idea if you don't have the wheels blocked.

I have had this happen a couple of times and simply putting the coach into reverse has freed the stuck brake. You don't even roll a measurable distance, you just need the reverse pressure to get them to release.

Have your brake assembly checked to see what is causing this! Could be a flat spot on the brake cam or a weak return spring. Good Luck