Air Brake Test Reading 3 — Questions and Answers
Question 1: According to standard air brake guidance, how should you brake on a long downhill grade?
- Hold the brakes down firmly the whole way
- Use a low gear and proper braking technique (Correct answer)
- Coast in neutral
- Pump the brakes rapidly the entire descent
Correct answer: Use a low gear and proper braking technique
The primary brake on a long grade is the engine; select a low gear and use the brakes properly.
Question 2: Reading the rule for stab braking on a downgrade, what is the correct sequence?
- Apply lightly and never release
- Apply fully, then release when you slow about 5 mph below safe speed, repeat (Correct answer)
- Pump rapidly without full application
- Apply only the trailer brakes
Correct answer: Apply fully, then release when you slow about 5 mph below safe speed, repeat
Stab braking means applying the brakes fully, releasing when slowed about 5 mph below your safe speed, then repeating.
Question 3: What does the air brake manual say causes brake drums to overheat?
- Light, intermittent braking
- Excessive use of the service brakes on long grades (Correct answer)
- Using engine braking
- Driving uphill
Correct answer: Excessive use of the service brakes on long grades
Excessive use of the service brakes, such as riding them down a grade, causes overheating and fade.
Question 4: When the manual describes brake lag, what is it referring to?
- Delay before air-applied brakes take effect compared to hydraulic (Correct answer)
- The time to fill the fuel tank
- Engine warm-up time
- Tire pressure loss
Correct answer: Delay before air-applied brakes take effect compared to hydraulic
Air brakes take longer to work than hydraulic brakes because air must travel through the lines, called brake lag.
Question 5: Reading total stopping distance guidance, which factor is added for air brakes that hydraulic brakes do not have?
- Perception distance
- Reaction distance
- Brake lag distance (Correct answer)
- Steering distance
Correct answer: Brake lag distance
Air brakes add brake lag distance to perception, reaction, and braking distance.
Question 6: What does the guidance recommend you do before starting down a long, steep grade?
- Speed up to build momentum
- Slow down and shift to a low gear (Correct answer)
- Release the parking brake fully and coast
- Turn off the engine
Correct answer: Slow down and shift to a low gear
You should slow down and shift to a low gear before descending a long, steep grade.
Question 7: Per air brake instructions, what is the proper following distance increase in bad weather or poor traction?
- Reduce following distance
- Keep it the same
- Increase the following distance (Correct answer)
- Following distance does not matter
Correct answer: Increase the following distance
Poor traction and bad weather require increasing your following distance for safe stopping.
Air Brake Test Reading 3
According to standard air brake guidance, how should you brake on a long downhill grade?