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Section Summary Questions

  1. What is the basic principle of the dual circuit system?
  2. What valve is used to protect the primary circuit from the secondary circuit?
  3. In a simple dual circuit system, will the vehicle continue to have braking ability if one circuit fails?
  4. Is there a difference between the foot valve used in a single circuit system and the foot valve used in the dual circuit system?
  5. Name two functions of the spring brakes in a dual circuit system.
  6. Describe the functions of the spring brake modulator valve.
  7. If the trailer breaks away from the tractor on a dual circuit highway system, what applies the brakes on the trailer?
    1. the trailer reservoir pressure
    2. the spring brakes
  8. What is blended air?
  9. Can a single circuit trailer be towed with dual circuit tractor?
  10. Name the components found on an L-75 system that are not on a dual circuit ‘highway’ system.
  11. If the trailer breaks away from the tractor on an L-75 system, what applies the trailer brakes?
    1. the trailer reservoir pressure
    2. the spring brakes if equipped