[C10 - C90 Bill]

Sounds like your truck didn't have Maxi-Brakes or Spring Brakes as some will call it. Maxi-Brakes are a reverse process emergency brake. It's the button on the dash that gets pulled to activate the air pressure emergency brake when parked. The safety factor is that you need pressure to release it and take off the pressure to activate it. When you lose Air Pressure while driving, it is supposed to automatically stop the truck.

Although, luckily, I never got to ever experience that on my '71 9500 that had them. My old '62 6500 also had Air Brakes but no Maxi though. I always had plans on what to do if I lost pressure (Hit that almost use-less Hand Brake and start Downshifting, lol). But it was a Gas engine which would help it to stop better in comparison.

But luckily again, I never lost pressure in that truck, on a normal road anyway. Had one scare though. A full load of about 20,000 going down a steep hill. The Buzzer kicked on and I started to panic a little, but made it to the bottom OK.