Anti gel for frozen trailer air lines?

I don't think you should do that. Just hit it with a hammer a couple times until it rings. When they get frozen on it's just a thin film of water ice bonding the shoe to the drum.

 

Bigger risk is the rapid temperature change in a small area. Or burning yourself.

 

One thing I learned early on from the old man was if the truck doesn't roll or start to move while in friction zone of the clutch then put the clutch pedal back in, shift to reverse and gently ease the clutch out to the friction zone again and see if the frozen brake shoe comes loose. Typically on each wheel one shoe will want to pull tighter into the drum and the other won't, so if you try and gently apply torque in the opposite direction the frozen shoe will sometimes loosen up without needing to beat or heat the drum.

When I say gently I mean literally ease out the clutch to the friction point where the engine just starts to lug down. All that torque at low RPM combined with a low starting gear will tear stuff apart like nothing if you get too aggressive.

 

So rev it up to 1300 and dump the clutch? Got it.

 

I usually use a tire bar on shoes frozen to drum. Put the bar under the end of the shoe on the cam side, and pry up on the bottom shoe, down on the top shoe.

Simple, easy, safe

Often, only the bottom is frozen to the drum

 

Living in Canada, this happens all the time. Get a 3 pound dead blow hammer, not a claw hammer. Release your trailer brakes, and hit the bottom of the brake drum, not the lining. You will hear them pop. Air brake antifreeze is used if you have a frozen valve somewhere in the system.