CDL Air Brakes Test 4 – Classic Mode

1. Air loss in a straight truck or bus should not be more than ____ with the engine off and the brakes released.

A 1 psi in 30 seconds
B 1 psi in one minute
C 2 psi in one minute
D 3 psi in one minute

2. To make an emergency stop with air brakes, using the stab braking method, you should:

A Pump the brake pedal rapidly and lightly.
B Brake hard until the wheels lock, and then get off the brakes for as much time as the wheels were locked
C Brake as hard as you can, get off the brakes when the wheels lock, get back on the brakes when the wheels start rolling again.
D Press hard on the brake pedal and apply full hand valve until you stop.

3. You should know that your brakes are fading when:

A Pressure on the brake pedal is released and speed increases.
B You have to push harder on the brake pedal to control your speed on a downgrade.
C The brake feels spongy when pressure is applied
D Less pressure is needed on the brake pedal for each stop

4. To check the free play of manual slack adjusters on s-cam brakes you should:

A Park on level ground, chock the wheels, and release the parking brakes.
B Stop on level ground and apply the parking brakes.
C Park on level ground and drain off air pressure before adjusting.
D Park on a slight grade, release the parking brake, apply the service brakes, and check for vehicle movement.

5. If the air compressor should develop a leak, what keeps the air in the tanks?

A The tractor protection valve
B The emergency relay valve
C The one way check valve
D The air compressor

6. When driving down a long steep hill you should:

A Use stab braking.
B Begin braking when you are 10 M.P.H. above your safe speed.
C Release the brake when you are 5 M.P.H. below your safe speed.
D Use the trailer brakes.

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

A Service brake system.
B Emergency brake system.
C Parking brake system.
D None of the above.

8. The most common type of foundation brakes found on heavy vehicles is the:

A Disc brakes
B Wedge drum
C S-cam drum
D None of the above

9. Vehicles with air brakes must have:

A At least two air tanks.
B An air pressure gauge to show the pressure available for braking.
C An air pressure gauge, to show air used by the brake chambers for braking.
D None of the above.

10. The driver must be able to see a warning that is given before air pressure in the service air tanks falls below:

A 80 psi
B 40 psi
C 20 psi
D 60 psi

End of Test #4

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