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The air brakes endorsement applies to applicants who wish to drive a vehicle with air brakes in Class A, B, or C CDL. To drive a vehicle with air brakes, you must pass the air brake component of the Delaware CDL knowledge test. The DE CDL air brakes test consists of 25 questions, and you'll need at least 20 correct answers to pass (80%). The test covers the information found in the air brakes section of the Delaware CDL Manual. Take this DE CDL practice test now to prepare for the actual air brakes test!
1. To brake in a way that will keep your vehicle in a straight line and allow you to turn if it becomes necessary, you can use:
the "controlled braking" method.
the "controlled braking" method or the "stab braking" method.
the "stab braking" method.
None of the above.
2. The air storage tanks:
protects the tank and the rest of the system from too much pressure.
stop the compressor from pumping air.
are used to hold compressed air.
are connected to the engine through gears or a v-belt.
3. When the air system is fully-charged, the air loss rate for a single vehicle with the engine off should be less than:
4 psi in one minute.
3 psi in one minute.
2 psi in 30 seconds.
2 psi in one minute.
4. Most heavy-duty vehicles use:
pump-the-brake systems.
dual air brake systems.
single air brake systems.
triple air brake systems.
5. Air tanks usually hold enough compressed air to allow the brakes to be used _________ even if the compressor stops working.
for 3 days
for one day
for one stop
several times
6. Spring brakes are usually held back by:
the antilock braking system.
the brake pedal.
modulating control valves.
air pressure.
7. The tire load rating is stated:
on each axle.
inside the suspension system.
on the dashboard.
on the side of each tire.
8. The supply pressure gauges tell you how much air pressure:
is going to the brake chambers.
is in the air brakes.
you are applying to the brakes.
is in the air tanks.
9. The use of brakes on a steep downgrade is:
much more effective than the engine braking effect.
a supplement to the braking effect of the engine.
the main braking factor.
dangerous, and should be avoided at all costs.
10. The total stopping distance for vehicles with air brake systems is made up of __ different factors.
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DE CDL Air Brakes Test

Number of questions: 25
Correct answers to pass:20
Passing score:80%
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