Some older vehicles with air brakes have front brake limiting valves. These valves were intended to reduce the risk of front wheels skidding. However, research has shown that such devices are unnecessary, so they should be left in the "normal" position.

Prevent the front tires from skidding.

Prevent the front tires from overheating.

Remove uncertainty when applying the brakes.

In an air brake system, the air tanks must be periodically drained to remove accumulations of water and compressor oil. If water is not removed, it could freeze in cold weather and cause brake failure.

Water accumulations freezing and causing brake failure.

Too much air collecting in the tanks.

The function of an Anti-Lock Braking System (ABS) is to prevent the vehicle's wheels from locking up from hard brake application.

Help a driver avoid wheel lockup

Prevent a vehicle from accelerating while traveling uphill

Prevent a vehicle from accelerating while traveling downhill

Brakes are designed to take a lot of heat, but drivers should not rely solely on the brakes to slow their vehicle. Brakes may fade and lose their ability to slow down the vehicle if they become too hot, so drivers should also rely on the engine braking effect.

The brakes may squeak more than usual.

The brakes will brake unevenly.

Compressed air usually contains a certain amount of moisture and compressor oil, which can build up in the air storage tanks and damage the brake system. The tanks should be drained to clean out these accumulations. On a tank with a manual drain valve, draining should be performed at the end of each day of driving.

Because compressed air contains some water and the water collects in the tanks

Because the air gets old and needs to be replaced

Because compressed air contains some water and the water collects in the tanks

To allow for a change in pressure

An air compressor governor will stop the compressor from pumping air once the air tanks are at an air pressure level around 125 psi. This air pressure level is referred to as the "cut-out" level.

Stop the compressor from pumping air.

Begin pumping air into the tanks.

Air Brakes Endorsement Test | Montana 2026 #2 Page 4 of 4

Train for FREE online with our Montana 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 MT Class A/Class B driver license in 2026, 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.

Number of Question 25

Passing Score 20

Number of Tests 20

Air Brakes Endorsement Test | Montana 2026 #2 Page 4 of 4

19 . During a walk-around inspection, ensure there are no cracks on the brake drums that are more than ____ of the width of the friction area.

20 . Front brake limiting valves were intended to:

21 . Failing to drain air tanks could result in:

22 . What do anti-lock brakes do?

23 . Using the brakes creates heat. If too much heat is produced:

24 . Why should you regularly drain the air tanks?

25 . Once the air tanks are at an air pressure level of 125 psi, the air compressor governor will:

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