DMV Class B License Test: Air Brakes Endorsement QA

DMV Class B License Test: Air Brakes Endorsement Q&A

Excessive use of the service breaks results in overheating, which can lead to:

a) Improper adjustment of the S-cam

b) Increased contact between the brake drums and brake linings

c) Expansion of the brake drums Correct Answer - c) Expansion of the brake drums

If air pressure does NOT build up to normal within the correct amount of time:

a) You should be ready to use your parking brake to help stop

b) The alcohol container may be low

c) Your air pressure may drop too low during driving Correct Answer - c) Your air

pressure may drop too low during driving

If you must make an emergency stop, you should brake so you:

a) Use the hand brake before the brake pedal

b) Use the full power of the brakes to lock them

c) Can steer and your vehicle stays in a straight line Correct Answer - c) Can steer and

your vehicle stays in a straight line The proper method of braking when going down long and/or steep grades, after selecting the proper gear, is to brake until your speed is about ___ MPH below your "safe" speed, then release your brakes

• 5
• 10
• 15 Correct Answer - a) 5

Your bus or truck has a dual air brake system. If a low air pressure warning comes on only for one system, what should you do?

a) Reduce your speed and drive to the nearest garage for repairs

b) Reduce your speed and test the remaining system while driving 1 / 2

c) Stop and safely park. Continue only after the system is fixed Correct Answer - c) Stop

and safely park. Continue only after the system is fixed The driver must be able to see a warning before air pressure in the service tanks falls below ___ psi.

• 50
• 60
• 80 Correct Answer - b) 60

The parking or emergency brake on a heavy vehicle can only be held in position by something

cannot leak away, like:

a) Spring pressure

b) Air pressure

c) Hydraulic pressure Correct Answer - a) Spring pressure

Before driving a truck or bus with a dual air brake system, the pressure in each system should be at least ___ psi.

• 80
• 100
• 120 Correct Answer - b) 100

The brake system that applies and releases the brakes when the driver uses the brake pedal is the ___ brake system.

a) Emergency

b) Service

c) Parking Correct Answer - b) Service

Controlled braking:

a) Involves locking the wheels for short periods of time

b) Is used to keep a vehicle in a straight line when braking

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