ASSIGNMENT  3 Textbook  Assignment: “Chassis  Systems,”   “Electrical  and  Hydraulic  Systems,”and  “Rules  of the Road,” pages 3-24 through 5-6. Learning  Objective: Recognize the  principles  and  components of air,   air–over–hydraulic,   and vacuum  brake  systems. 3–1. An  air  brake  system  uses  compressed air to apply the brakes. 1. True 2. False 3–2. In an air brake system, what component  pumps  air  into  the storage 1. The 2. The 3. The 4. The 3-3. At what tanks? governor evaporator air  compressor master  cylinder  pump pounds  per  square  inch (psi) of air pressure does a governor  stop  the  compressor from  pumping  air? 1. 30 2. 60 3. 90 4. 120 3–4. Compressed  air  usually  contains water  and  compressor  oil. 1. True 2. False 3–5. Which of the following components of an air brake system helps reduce the risk of ice in air brake valves? 1. Safety  valve 2. Treadle  valve 3. Alcohol  evaporator 4. Limiting  quick–release  valve 3-6. Which  of  the  following  components of an air brake system protects the tank and the rest of the system from too much air pressure? 1. The 2. The 3. The 4. The safety  valve alcohol  evaporator drain  cock slack  adjuster 3-7. When the brake pedal is engaged, air from the air tank flows through what  component  before  flowing through  the  brake  lines  connected to  the  brake  chambers? 1. Double–check  valve 2. Brake  pedal  valve 3. Limiting  quick-release  valve 4. Hand brake valve 3-8. Pressing  and  releasing  the  brake pedal  unnecessarily  may  release  air out faster from the air tank than the compressor can replace it. 1. True 2. False 3-9. A low air warning device should cut on before the pressure in the air tank(s) drops lower than what pressure? 1. 120  psi 2. 90  psi 3. 60  psi 4. 30  psi 3–10. On  a  tractor-trailer  equipped  with air brakes, which of the following components  provides  the  operator control of the trailing load at all times? 1. Master  cylinder  valve 2. Hand brake valve 3. Trailer  protection  valve 4. Double-check  valve 17