Washington CDL Air Brakes Practice Test (WA) 2

5 out of 5 (45 votes)
80% Passing score
20 Questions
4 Mistakes allowed
Get ready to master the intricacies of the Washington state CDL air brakes endorsement with this thorough Washington CDL air brake practice test. Designed with the diverse needs of WA's drivers in mind, this test features 20 multiple-choice questions that cover essential topics such as the components of air brake systems, safe operation procedures, crucial safety inspections, and calculations for stopping distances. Whether you're navigating the hilly terrains of the Cascades or dealing with the heavy rainfall typical of the Pacific Northwest, understanding how air brakes function is crucial for maintaining safety on Washington state's roads. This Washington knowledge test practice isn't just about rote memorization-it's about truly understanding how to operate a commercial vehicle safely. WA's varied climate and challenging driving conditions, from foggy mornings in Seattle to icy roads in Spokane, mean that being well-prepared is more than just a necessity-it's a responsibility. The DOL air brake test is structured to ensure that drivers are equipped with the knowledge they need to handle these conditions with confidence. To ensure you're fully prepared, this Washington state air brakes CDL test draws directly from the official Washington State Commercial Driver's Manual. If it's in the manual, it's on the test-guaranteeing that your study efforts are focused on the most relevant information. For additional preparation, consider using supplementary materials like the WA State Driver's Handbook, state-certified drivers education courses, flashcards, and road sign charts. These resources, combined with this practice written driving test, will help you target all areas of the DMV permit test and increase your chances of success. To help you study more effectively, this DOL practice test includes built-in study aids. If you find yourself struggling with a question, you can use the hint feature to guide you towards the correct answer. And if you answer incorrectly, the test provides detailed explanations to help reinforce your understanding. With a passing score requiring 16 correct answers out of 20, this Washington state CDL air brake practice test offers a comprehensive and user-friendly approach to mastering the air brakes section of your CDL test.
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Sample Washington Air Brakes Test Questions

Question 1

On a truck, tractor, or bus, which indicator shows that the vehicle is equipped with ABS?

  1. A A red ABS lamp on the instrument panel
  2. B A yellow ABS malfunction lamp on the instrument panel
  3. C A yellow lamp on the vehicle’s left rear corner
  4. D A red lamp on the vehicle’s right side

Correct answer: B – A yellow ABS malfunction lamp on the instrument panel

Tractors, trucks, and buses equipped with ABS have a yellow ABS malfunction lamp on the instrument panel. On newer vehicles, the lamp normally comes on briefly during the start-up check and then goes out. The Washington guide distinguishes this from a trailer’s yellow ABS lamp, which is mounted on the trailer’s left side.

Source: Washington State Commercial Driver Guide — § 5.1.16, “Antilock Braking Systems (ABS)”

Question 2

True or false: An air brake system includes service, parking, and emergency braking systems.

  1. A True
  2. B False

Correct answer: A – True

Air brakes are described as three braking systems. The service brake system operates through the brake pedal during normal driving, while the parking brake system holds the parked vehicle. The emergency brake system uses parts of the service and parking systems to stop the vehicle if the brake system fails.

Source: Washington State Commercial Driver Guide — Section 5, “Air Brakes”

Question 3

What is the function of the air compressor governor?

  1. A It controls when the compressor pumps air into the storage tanks
  2. B It determines how much pressure the brake pedal applies
  3. C It indicates whether the compressor needs repair
  4. D It controls the compressor’s engine speed

Correct answer: A – It controls when the compressor pumps air into the storage tanks

The governor controls when the air compressor begins and stops pumping air into the storage tanks. It starts compressor operation at the cut-in pressure and stops it when pressure reaches the cut-out level. A malfunctioning governor may prevent the air brake system from maintaining adequate pressure.

Source: Washington State Commercial Driver Guide — § 5.1.2, “Air Compressor Governor”

Question 4

True or false: With the service brake fully applied, a combination vehicle may lose no more than 4 psi in one minute after the air gauge stabilizes.

  1. A True
  2. B False

Correct answer: A – True

The applied-brake leakage limit is 3 psi in one minute for a single vehicle and 4 psi in one minute for a combination vehicle. A greater pressure loss indicates excessive leakage that must be corrected before driving. Washington’s inspection procedure measures the loss while full brake-pedal pressure is held for one minute after the gauge stabilizes.

Source: Washington State Commercial Driver Guide — § 5.3, “Test Air Leakage Rate”

Question 5

Which substance is intended to serve as the working medium in an air brake system?

  1. A Water
  2. B Compressed air
  3. C Compressor oil
  4. D A mixture of air, water, and oil

Correct answer: B – Compressed air

Compressed air operates the brake system. Water and compressor oil can enter and collect in the air storage tanks, but they are contaminants rather than intended working materials. Tanks without automatic drains should be drained regularly because accumulated moisture or oil can damage the system or contribute to brake failure.

Source: Washington State Commercial Driver Guide — § 5.1.3, “Air Storage Tanks”; § 5.1.4, “Air Tank Drains”

Question 6

True or false: The two parts of a dual air brake system are called the primary and secondary systems.

  1. A True
  2. B False

Correct answer: A – True

A dual air brake system consists of two separate systems operated by one set of brake controls. Each has its own air tanks, hoses, and lines. One is called the primary system and the other is called the secondary system, providing braking capability through separate portions of the vehicle’s brake system.

Source: Washington State Commercial Driver Guide — § 5.2, “Dual Air Brake”

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