Air Brake Test Reading 3

Question 1

According to standard air brake guidance, how should you brake on a long downhill grade?

Accepted Answer

Use a low gear and proper braking technique

Answer

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?

Accepted Answer

Apply fully, then release when you slow about 5 mph below safe speed, repeat

Answer

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?

Accepted Answer

Excessive use of the service brakes on long grades

Answer

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?

Accepted Answer

Delay before air-applied brakes take effect compared to hydraulic

Answer

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?

Accepted Answer

Brake lag distance

Answer

Air brakes add brake lag distance to perception, reaction, and braking distance.

Air Brake Practice Test