CDL Air Brakes Practice Test 2025: Endorsements Permit Test

The ________ system applies and releases the brakes when you use the brake pedal during normal driving

To test the low pressure warning signal, all of the following must be done except:

How often should you drain your air tanks?

Air brakes are really three different braking systems:

What part of the braking system is used to adjust the brakes?

_________ does not necessarily shorten your stopping distance, but it does help you keep the vehicle under control during hard braking

For dual air systems, air pressure should build

The _______ system applies and releases the parking brakes when you use the parking brake control

When the tank pressure falls to the "cut-in" pressure (around ____ psi), the governor allows the compressor to start pumping again.

Pressing and releasing the pedal unnecessarily can let air out faster than the compressor can replace it. If the pressure gets too low, the __________ won't work.

Do not use parking brakes if the brakes are very hot or if the brakes are very wet in freezing temperatures.

What is the maximum leakage for a combination of 3 or more vehicles in the Applied Leakage Test?

The __________ system uses parts of the service and parking brake systems to stop the vehicle in a brake system failure.

What keeps air from going out if the air compressor develops a leak?

This type of brake is a parking brake held on by mechanical force.

Which of the following factors can cause brakes to fade or fail?

When making a normal stop in a manual transmission vehicle you should engage the clutch __________

The __________ protects the tank and the rest of the system from too much pressure

Which vehicles must have low air pressure warning signals?

What brake system has 2 separate air brake systems, which use a single set of brake controls?

The __________ pumps air into the air storage tanks (reservoirs).

__________ are most often used for emergency and parking brakes

Foundation brakes are used at each wheel. The most common type is the __________ brake.

There are special braking procedures you must follow when driving a tractor trailer combination with ABS?

A warning signal you can see must come on before the air pressure in the tanks falls below ______ psi.

If the safety valve releases air, the air braking system is working properly.

The air compressor should cut out no higher than ___ psi and should cut in no lower than ___ psi for a bus, and no lower than ___ psi for trucks.

While driving down long, steep downgrades, your brakes

Compressed air usually has some __________ in it, which is bad for the air brake system.

In newer vehicles with air brakes, you put on the __________ using a diamond-shaped, yellow, push-pull control knob.

All vehicles with air brakes have a pressure gauge connected to the __________.

A slack adjuster needs adjustment if it move more than how many inches from where the push rod attaches to it?

Front wheel braking is good under all conditions.

The __________ controls when the air compressor will pump air into the air storage tanks.

__________ are used to hold compressed air

What is the maximum leakage rate for single vehicles in the Applied Leakage Test?

Tractor and straight truck spring brakes will come fully on when air pressure drops to a range of _________ psi

The braking power of spring brakes depends on the brakes being in adjustment. If the brakes are not adjusted properly, __________ will work right.

This gauge shows how much air pressure you are applying to the brakes

Never push the brake pedal down when the spring brakes are on

Air brakes use __________ to make the brakes work

To test that spring brakes come on automatically, all of the following are true except:

The use of brakes on a long, steep downgrade is only a supplement to the braking effect of the engine.

What is the maximum leakage for a combination of 2 vehicles in the Applied Leakage Test?

What gauge tells you how much pressure is in the air tanks?

Compressed air usually has some water and some compressor oil in it, which is bad for the air brake system. The water can freeze in cold weather and cause brake failure

What pumps air into the air storage tanks?

Front wheel brakes are only good for driving under wet or icy conditions.

When air tank pressure rises to the "cut-out" level (around __________ or psi), the governor stops the compressor from pumping air

You should be in the proper gear before starting down a hill.