Air Brakes (pt 1)

Question 1

What are the main components of the air brake system? (other than the brakes themselves)

Answer 1

1. Air compressors: 2 compressors (+1 for air step system)
2. Air governor: brain that monitors and engages air compressor when needed
3. Air Dryer: cools, filters, and dries air before goes in air tanks
4. Air tanks: 5-7; with petcock

Question 2

What happens when I depress the brakes?

Answer 2

1. Air enters drum and engages push rod to push slack adjuster
2. The slack adjuster turns the S cam against the cam rollers
3. This pushes the brake shoes against the brake drum

Question 3

Describe the parking brakes?

Answer 3

1. Releasing parking brake causes air to enter the chamber and compress the spring (Compressed air keeps the spring brake compressed)
2. Engaging the parking brake expels air and the spring engages the push rod which engages the service brakes [if during normal driving, the pressure where to be lost from the system it would do this same thing]