AIR BRAKES CDL PRACTICE TEST - DISTRICT OF COLUMBIA
6.
The parking or emergency brakes of trucks or buses must be held on by:
|
spring pressure.
|
|
|
fluid pressure.
|
|
|
hydraulic pressure.
|
|
|
air pressure.
|
7.
On
a tractor-trailer equipped with a trailer brake hand
valve, the hand valve can be used to:
|
prevent movement of cargo.
|
|
|
hold compressed air.
|
|
|
keep from rolling back.
|
|
|
reduce the chance of the front wheels skidding.
|
8.
With a fully-charged air system, the leakage rates should be less than:
|
5 psi for single vehicles and 10 psi for a combination of two vehicles.
|
|
|
5 psi for single vehicles and 4 psi for a combination of two vehicles.
|
|
|
2 psi for single vehicles and 3 psi for a combination of two vehicles.
|
|
|
3 psi for single vehicles and 4 psi for a combination of two vehicles.
|
9.
A low air pressure warning signal:
|
is required on vehicles with air brakes.
|
|
|
is required on all vehicles without air brakes.
|
|
|
is optional on vehicles with air brakes.
|
|
|
None of the above.
|
10.
If your vehicle has dual parking control valves, you can use pressure from a separate tank to:
|
park better.
|
|
|
balance the service brakes while you are parked.
|
|
|
release the spring brakes so you can move the vehicle in an emergency.
|
|
|
None of the above.
|
Next page
NOT SURE YOU WILL PASS? GET CDL PREMIUM NOW! - Learn More