Michigan CDL Air Brakes Study Guide 2023

3 different braking systems that make up Air Brakes - Service Brake, Parking Brake, Emergency Brake Air Compressor - Pumps air into storage tanks and connected to the engine via gears or a v-belt. Air Compressor Governor - Controls when the air compressor will pump air into the air storage tanks. When tank pressure rises to the cut-out level, the governor stops the compressor from pumping. When the tank pressure falls to the cut-in level, the governor allow the compressor to pump again. Cut-Out Level - 125 PSI (Governor stops the compressor from pumping air) Cut-In Level - 100 PSI (Governor allows compressor to start pumping again) Air Storage Tanks - Holds the compressed air. Air Tank Drains - Valve to drain oil and water from the tanks. Alcohol Evaporator - Puts alcohol into the air system to reduce risk of ice in the valves. Safety Valve - In the first take air is pumped in to...protects the tank and system from too much pressure. Set to open at 150 PSI. Foundation Brakes - Used at each wheel...most common type is the S-Cam drum brake. Drums, Shoes and Linings - Drums located on each end of the axles. Wheels are bolted to the drums. To stop, the brake shoes and linings are pushed against the inside of the drum. S-Cam Brakes - Pressure pushes the rod out, moving the slack adjuster, thus twisting the brake camshaft. Forces the brake shoes away from one another and presses them against the inside of the brake drum. Supply Pressure Gauges - Tells you how much pressure is in the air tanks. Will be one for each half the the brake system in dual air brake systems. Application Pressure Gauge - Shows how much pressure you are applying to brakes. (Not on all vehicles). Increasing pressure to hold same speed means brakes are fading. Slow down and use lower gear.