Air Brakes #2
Air Brakes Endorsement Test | Massachusetts 2025 #2 Page 4 of 4
Train for FREE online with our Massachusetts CDL air brake test. The official exam test consists of several obligatory parts, with all of them checking your knowledge of different blocks of road rules. If you need to obtain a MA Class A/Class B driver license in 2025, practice as much as possible. Free sample tests published on our website will help you check and improve your knowledge and boost your grades. Please bear in mind that the requirements for CDL may vary from state to state.
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19 . Before driving a vehicle with air brakes, you should ensure that the spring brakes come on automatically when:
Driving uphill.
Before driving a vehicle with air brakes, you should ensure that the spring brakes come on automatically when air tank pressure falls to a level between 20 and 45 psi. You can do this by chocking the wheels and releasing air from the braking system by stepping on and off the brake pedal. Once the pressure drops to an unsafe level, the parking brake valve should pop out and spring brakes should come on.
20 . Before driving a vehicle with a dual air brake system, you must wait for the air compressor to build a minimum of ____ in both the primary and secondary systems.
100 psi
Before driving a vehicle with a dual air brake system, you should wait for the air compressor to build up at least 100 psi in both the primary and secondary systems.
21 . Before a vehicle with dual air brakes is driven, pressure of at least ____ should be built up in both braking systems.
100 psi
Before driving a vehicle with a dual air brake system, allow time for the air compressor to build up pressure of at least 100 psi in both the primary and secondary systems.
22 . Test the low pressure warning signal:
Before every trip.
It is essential that your low pressure warning light function properly. After allowing the system to charge, you can test the warning signal by rapidly applying and releasing the brake pedal. This will release air from the braking system and the warning signal should come on when pressure drops to a dangerous level.
23 . Why do large vehicles use air brakes?
Air is free.
Air brakes are an effective and safe way of stopping large and heavy vehicles, as long as they are maintained and used properly.
24 . The ____ tells a driver how much pressure is in the air tanks.
Drum brake
A vehicle that is equipped with air brakes must also be equipped with a supply pressure gauge. This gauge tells the driver how much air pressure is in each of the vehicle's air tanks.
25 . Air tank drains:
Must remain open while driving.
