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Difficulty: MediumVehicle Mechanical Emergencies

While descending a steep mountain grade, a driver notices that continuous braking has caused the brakes to overheat and lose stopping effectiveness (brake fade). Which of the following is the most appropriate primary action to control and reduce the vehicle's speed?

  1. Shift the transmission into a lower gear to utilize engine braking.Answer
  2. B
    Apply continuous, maximum force onto the brake pedal to lock the wheels.
  3. C
    Increase speed slightly to reach the flat terrain at the bottom of the incline more quickly.
  4. D
    Rapidly turn the steering wheel side to side to create friction between the tires and the roadway.

Answer

Shift the transmission into a lower gear to utilize engine braking.
Shifting into a lower gear engages engine braking, which uses engine compression to regulate speed down steep hills and prevents overheating of the service brakes.

Step-by-Step Solution

1
Identify the cause of reduced braking efficiency on downhill slopes.
Recognize that thermal buildup from continuous braking leads to brake fade.
Excessive heat prevents friction materials from gripping the brake rotors or drums effectively.
2
Select a mechanical engine control measure to slow the vehicle without relying solely on friction brakes.
Shift into a lower transmission gear.
Engine braking uses internal engine resistance to maintain or reduce vehicle speed safely.

Key Concept

Brake Fade and Engine Braking on Steep Downgrades
Estimated Time:1m 0s
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Topics

Vehicle Mechanical Emergencies

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