bummed out

That should happen but if there's an air leak it may not... I actually saw this happen at the terminal of my old company... truck rolled back into the fuel island. The spring brakes are pressurized so when you pull the knob air is pushed into the spring chamber but if no air is ported to the chamber that doesn't work. I don't think OP should be failed for performing the test correctly in any case and that's the only thing I could think of... Unless of course he was asked about one of the other 6 brake tests and did the pump down instead. In that case he'd be wrong.

 

I think you got things mixed up with that statement, sir. When their is "No Air" in the chamber the spring brakes are always activated. When air is in the tanks that is what release the spring breaks. This is why if you get an air leak going down the highway you need to pull over, or those spring brakes will activate and that can be bad news for who ever is behind you and god knows what else. Sounds like the truck that rolled into the fuel island, driver forgot to pull his knobs which allowed the truck roll completely free. That or he only pulled out the tractor valve and the trailer if loaded pulled the tractor with it.

GL op on finishing up that test to get that CDL A.