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CDL AIR BRAKES TEST..docx, Exams of Refrigeration and Air Conditioning

Western Governors University (WGU)Refrigeration and Air Conditioning

CDL AIR BRAKES TEST..docx, 2026

Typology: Exams

2025/2026

Available from 01/04/2026

alex-david-32
alex-david-32 🇺🇸

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CDL AIR BRAKES TEST .
In air brake vehicles, the parking brake should be used:
any time the vehicle is parked
Repeatedly pressing and releasing (fanning) the brake pedal may
result in:
the loss of brake pressure
If the spring brakes are on, when should you push the brake pedal?
never
How should you check that the trailer brakes come on when air
pressure in the system drops below a certain level?
chock the wheels, apply the parking brake, shut the engine off and
pump the brake pedal to reduce air tank pressure
The most common type of foundation brake found on heavy vehicles
is the:
s-cam drum
You should know your brakes are fading when:
you have to push the brake pedal harder to control speed on a
downgrade
The air loss rate for a straight truck or bus with the engine off and
the brakes on should not be more than:
3psi in one minute
The brake pedal in an air brake system:
controls the air pressure applied to put on the brakes
Truck and bus parking or emergency brakes must be held on by:
air pressure
The air brake lag distance at 55mph on dry pavement adds about __
feet to your stopping distance:
pf3
pf4
pf5

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CDL AIR BRAKES TEST.

In air brake vehicles, the parking brake should be used: any time the vehicle is parked Repeatedly pressing and releasing (fanning) the brake pedal may result in: the loss of brake pressure If the spring brakes are on, when should you push the brake pedal? never How should you check that the trailer brakes come on when air pressure in the system drops below a certain level? chock the wheels, apply the parking brake, shut the engine off and pump the brake pedal to reduce air tank pressure The most common type of foundation brake found on heavy vehicles is the: s-cam drum You should know your brakes are fading when: you have to push the brake pedal harder to control speed on a downgrade The air loss rate for a straight truck or bus with the engine off and the brakes on should not be more than: 3psi in one minute The brake pedal in an air brake system: controls the air pressure applied to put on the brakes Truck and bus parking or emergency brakes must be held on by: air pressure The air brake lag distance at 55mph on dry pavement adds about __ feet to your stopping distance:

What is emergency controlled braking? you apply the brakes as hard as you can without locking the wheel The driver must be able to see a low air pressure warning which comes on before pressure in the service air tank falls below __ psi. 60 For air brake systems in good condition,the air compressor should start pumping at about ___ psi. 100 If your truck has a dual air brake system and one of the systems is low on pressure: either the front or rear brakes will not be fully operational The air compressor governor controls: when air is pumped into the tanks If your truck or bus has dual parking control valves, you can use pressure from a separate tank to: release spring emergency/parking brakes to move a short distance If your truck's air compressor has its own oil supply, when should you first check your level? before driving The stop light switch: turns on the brake You are on a steep downgrade and have reached your safe speed 40 mph. You would apply the service brakes until your speed to __mph. 35 The braking power of the spring brakes: depends on the service brakes being in adjustment The use of air brakes on downgrade is only a supplement to the: braking effect of the engine

expansion of the brake drum If the air pressure does not build up to normal within the correct amount of time: your air pressure may drop too low during driving The brake system that applies and releases the brakes when the driver uses the brake pedal is the _______ brake system. service To check for free play of manual slack adjusters on s-cam brakes, you should park on level ground: chock the wheels and turn off the brakes Under normal conditions, to engage the parking brake the driver must first: let the air out of the air brake system Total stopping distance for vehicles with air brakes is longer than that for vehicles with hydraulic brakes due to _____ ___ distance. brake lag Which of these is not proper time to apply the parking brakes. when you come down a steep grade and your brakes are very hot The air brake system for a straight truck or bus should not leak at a rate of more than _ psi per minute with the engine off and the brakes released: 2 Before driving a truck or bus with a dual air brake, the pressure in each system should be at least ___ psi 100 Your truck has a properly functioning dual air brake system and minimum size air tanks. The air pressure should build from 85 to 100 psi within. 45 seconds The air compressor should stop pumping at about ___ psi.

How should you check that your service brakes are working properly? wait for normal air pressure, release the parking brake, move the truck forward slowly, and firmly step on the brake Some air brake systems have an alcohol evaporator. What may happen if you don't keep the unit filled with alcohol? ice may form in the air storage tanks and cause the brake to fail Parking or emergency brakes of trucks and buses can be legally held on by ______ pressure. spring The proper method of braking when going down long and/or steep grades after selecting the proper gear, is to brake until, your speed is about _ miles per hour below your "safe speed" then release your brakes. 5 Air braking takes more time than hydraulic braking because air: takes more time to flow through the lines than hydraulic fluid Excessive heat caused by using your brakes too often can cause the brakes to fade or fail The spring brakes used on tractors and straight trucks will bring your truck to a stop when the air pressure drops below __ psi. 20