In Partnership with Marshall Public Library
View instructions
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 Idaho CDL knowledge test. The ID 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 Idaho CDL Manual. Take this ID CDL practice test now to prepare for the actual air brakes test!
1.
What is the best way to test the low air pressure warning signal?
|
step on and off the brake pedal while the engine is running.
|
|
|
Shut the engine off when you have enough air pressure, turn the electrical power on and step on and off the brake pedal to reduce air pressure to below 60 psi.
|
|
|
pump the brakes until the air pressure drops below 45 psi.
|
2.
The Johnson bar is a valve that:
|
reduces the braking pressure to a safe level.
|
|
|
is installed in the first tank the air compressor pumps air to.
|
|
|
works the trailer brakes.
|
3.
The low pressure warning signal will generally activate when the air pressure falls between:
|
55–75 psi.
|
|
|
80–85 psi.
|
|
|
85–100 psi.
|
4.
Rough acceleration:
|
improves gas mileage.
|
|
|
is necessary to warm up the engine.
|
|
|
can cause mechanical damage.
|
5.
When you release the brake pedal, the _____ rotates back and a spring pulls the brake shoes away from the drum.
|
S-cam
|
|
|
pressure gauge
|
|
|
air compressor belt
|
Next page