DMV Handbook

Question 1

Air brake systems are three braking systems combined. Name them.

Answer 1

Service brake: applies and releases the brakes when you use the brake pedal during normal braking.

Parking brake: applies and releases the parking brake when you use the parking brake control.

Emergency brake: uses parts of the service and parking brake systems to stop the vehicle in the event of a brake failure

Question 2

A full service brake application must deliver, to all brake chambers, what % of the air pressure remaining with the brakes applied?

Answer 2

Not less than 90%

Question 3

What are two other names for the brake pedal?

Answer 3

Foot valve

Treadle valve

Question 4

Where is the safety valve and what pressure is it set to?

Answer 4

Installed in the first tank pressure is pumped into

Set at 150 psi

Question 5

CamLaster and S-cam are two types of brakes. Which is self-adjusting and which requires an external slack adjuster?

Answer 5

CamLaster brakes are self-adjusting and S-cam brakes require an external slack adjuster.

Question 6

At what pressure should the spring brake activate?

Answer 6

Between 20-30. Powerful springs are held back by air pressure. When the pressure drops too low, the spring brake activates.

Question 7

What factors make up TOTAL STOPPING DISTANCE?

Answer 7

Perception distance
Reaction distance
Brake lag distance
Effective braking distance

Question 8

At 55 mph in good conditions, what is the total stopping distance?

Answer 8

Over 300 feet

Question 9

Air brake lag in seconds and feet at 55 mph

Answer 9

1/2 second or 32 feet