South Carolina CDL Permit Test - Air Brakes

Number of questions: 25
Passing score: 20
Directions: This endorsement is required for driving a vehicle with air brakes. To receive this endorsement, applicants must pass a written test. The test consists of 25 multiple choice questions. Each question has two, three or four answer choices. To pass, the applicant must answer at least 20 questions correctly. Test questions come from the South Carolina Commercial Driver License Manual. Questions come from the chapter covering: Air Brakes. The Air Brakes endorsement may be used with the Class A, B or C CDL.
You have made error so far
Passing grade —
5 or fewer errors
Using ABS:
Shortens stopping distance
Shortens brake response time
Provides less control
Provides more control
Vehicles with dual air brake systems:
Maintain air pressure in the braking system even when the vehicle is not running
Maintain some air pressure in the braking system when the vehicle is not running
Must be run to build air pressure to allow the brakes to operate properly
Should not be allowed time to build air pressure when the vehicle had not been running
What does the air compressor governor do?
Controls when the air compressor will pump air into the air storage tanks
Controls how quickly air leaves the air storage tanks
Controls the temperature of the air entering the air storage tanks
Controls the temperature of air leaving the air storage tanks
If a vehicle with air brakes has a low air pressure warning come on, the driver should:
Test the brakes while driving and if nothing seems wrong, continue driving
Pull over immediately
Drive with the hazard lights on
Air tank drains:
Should not be used in cold weather
Are helpful to remove water and oil from the air tanks
Are used to move air to the brakes
When do the spring brakes come on?
When main air pressure is lost
When a control on the dashboard is activated
When the tires have minimal tread depth
When the brakes are noisy
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