air brake questions

No, when you push on the brake pedal (treadle valve), it will force air into the system so the shoes will contact the drums, just like spring brakes but it is a separate system. The red air line puts air into the system so the spring brakes release and when you step on the brakes, the blue line carries the air to the brakes. I hope I explained that correctly.

 

Something was wrong with that. Both lines hold air...... That is why they are called air lines. Smile

 

The red line supplies constant air to compress the spring brakes. The blue line supplies air when the brakes are applied.

 

thanks for the information. Not sure how someone can pass the airbrake test without understanding that it is a dual system: the service brakes, and the parking/emergency brake system. How much weight loss are we talking about with the free movement of the wheels.