CDL AIR BRAKES ENDORSEMENT
CERTIFICATION EVALUATION SET 2026
PRACTICE QUESTIONS SOLUTIONS
VERIFIED
● To correct a drive-wheel braking skid, you should: Answer: Stop
braking and steer/counter steer
● The air compressor stops pumping air at what psi? Answer: 125
● Controlled braking: Answer: Is used to keep vehicle braking in a
straight line
● It is not safe to drive a vehicle that has brake drums (or discs) with
cracks or that are thinner than the manufacturer's specifications,
generally this will be_ an inch. Answer: 1/2
● What do air brakes use to make the brakes work? Answer:
Compressed air
● Excessive use of the service brakes results in overheating which can
lead to: Answer: Expansion of the brake drum
, ● The air brake lag distance at 55 mph on dry pavement adds about __
feet. Answer: 32 Feet
● Before driving a truck or bus with a dual air brake system, the
pressure in each air brake system should be at least__psi. Answer: 100
● The emergency brake system: Answer: Uses parts of the service and
parking brake system to stop the vehicle in the event of a brake system
failure
● The parking or emergency brakes of trucks or buses can legally be
held on by __ pressure. Answer: Spring
● The stop light switch: Answer: Turns on the brake lights to warn
drivers behind you
● The air supply pressure gauge shows how much pressure: Answer: is
in the air tanks
● Repeatedly pressing and releasing (fanning) the brake pedal may
result in: Answer: The loss of air brake pressure
● If the air compressor should develop a leak, what keeps the air in the
tanks? Answer: The one way check valve
CERTIFICATION EVALUATION SET 2026
PRACTICE QUESTIONS SOLUTIONS
VERIFIED
● To correct a drive-wheel braking skid, you should: Answer: Stop
braking and steer/counter steer
● The air compressor stops pumping air at what psi? Answer: 125
● Controlled braking: Answer: Is used to keep vehicle braking in a
straight line
● It is not safe to drive a vehicle that has brake drums (or discs) with
cracks or that are thinner than the manufacturer's specifications,
generally this will be_ an inch. Answer: 1/2
● What do air brakes use to make the brakes work? Answer:
Compressed air
● Excessive use of the service brakes results in overheating which can
lead to: Answer: Expansion of the brake drum
, ● The air brake lag distance at 55 mph on dry pavement adds about __
feet. Answer: 32 Feet
● Before driving a truck or bus with a dual air brake system, the
pressure in each air brake system should be at least__psi. Answer: 100
● The emergency brake system: Answer: Uses parts of the service and
parking brake system to stop the vehicle in the event of a brake system
failure
● The parking or emergency brakes of trucks or buses can legally be
held on by __ pressure. Answer: Spring
● The stop light switch: Answer: Turns on the brake lights to warn
drivers behind you
● The air supply pressure gauge shows how much pressure: Answer: is
in the air tanks
● Repeatedly pressing and releasing (fanning) the brake pedal may
result in: Answer: The loss of air brake pressure
● If the air compressor should develop a leak, what keeps the air in the
tanks? Answer: The one way check valve
