Maryland CDL Air Brakes Practice Test (MD) 2

4.9 out of 5 (73 votes)
80% Passing score
20 Questions
4 Mistakes allowed
As a future commercial driver in Maryland, it's crucial to be well-prepared for your air brakes endorsement, and our Maryland MVA practice test is here to help. This Maryland CDL air brakes practice test features 20 carefully crafted multiple-choice questions that mirror the style and content of the actual MVA permit test. By using this learner's permit practice test, you'll cover essential topics such as air brake components, operation, safety inspections, and stopping distance calculations. Maryland's diverse driving conditions, from the bustling streets of Baltimore to the scenic routes of the Chesapeake Bay area, demand a thorough understanding of your vehicle's braking system. This Maryland permit practice test includes vital information on dual air brake systems, enhancing your ability to handle emergency situations safely. Dual air brake systems provide a crucial backup, ensuring your safety and the safety of those around you in the event of a primary system failure. Our DMV permit practice test offers an authentic practice experience, closely mirroring the real MVA test in both content and format. While actual MVA test questions and answers are restricted, our test questions are designed to help you understand and retain the essential concepts. The multiple-choice format will aid you in mastering the skill of eliminating incorrect answers to find the correct one, just as you will need to do on the actual test. Maryland's varied landscape means that commercial drivers must be adept at handling a range of scenarios, from urban traffic to rural routes. This MD CDL air brake practice test ensures you're fully prepared for these challenges. To pass, you need to answer at least 16 of the 20 questions correctly. This comprehensive session will give you the confidence to tackle the Maryland MVA air brake test and excel. By dedicating time to this Maryland CDL air brakes practice test, you're investing in your future as a competent and confident commercial driver. Practice diligently, understand the core concepts, and soon you'll be navigating Maryland's roads with ease and expertise.
FREE CDL Practice Test App
Pass your Maryland CDL Air Brake test with the NextDoorDriving app. Real questions and answers—100% free and ad-free.
Download on the App Store

Sample Maryland Air Brakes Test Questions

Question 1

Which device protects a service air reservoir from pressure loss caused by a leak between the reservoir and its air source?

  1. A A one-way check valve
  2. B An emergency relay valve
  3. C A tractor protection valve
  4. D An air compressor governor

Correct answer: A – A one-way check valve

A one-way check valve allows the reservoir to be charged while protecting it from pressure loss back toward the air source. Federal safety standards require service reservoirs to have check valves or equivalent devices for protection against a failure or leak between the reservoir and its source. This protection does not cover leaks in every part of the brake system.

Source: 49 CFR § 571.121, S5.1.2.3, S5.2.1.4 – Standard No. 121; Air brake systems

Question 2

What is the purpose of an automatic slack adjuster?

  1. A To regulate air-tank pressure
  2. B To control spring-brake release pressure
  3. C To remove free play from the brake pedal
  4. D To maintain proper brake adjustment

Correct answer: D – To maintain proper brake adjustment

In an S-cam brake, the brake-chamber pushrod moves the slack adjuster, which turns the brake camshaft. The Maryland manual explains that automatic slack adjusters adjust during full brake applications, but they must still be inspected. Movement of more than about one inch where the pushrod attaches requires inspection for proper adjustment.

Source: Maryland Commercial Driver’s License Manual — § 5.1.8, “Foundation Brakes”; § 5.3.2, “During Step 5 Walk-around Inspection”

Question 3

Which air-brake component helps prevent ice from forming in valves during cold weather?

  1. A Air-compressor heater
  2. B Reservoir warming unit
  3. C Alcohol evaporator
  4. D One-way check valve

Correct answer: C – Alcohol evaporator

Some air-brake systems use an alcohol evaporator to introduce alcohol into the system. This reduces the risk of ice forming in valves and other components during cold weather. The alcohol container should be checked daily in cold conditions, and the device does not eliminate the need to drain moisture from the air tanks.

Source: Maryland Commercial Driver’s License Manual — § 5.1.5, “Alcohol Evaporator”

Question 4

In a spring-brake system, what holds the powerful springs back while the vehicle is being driven?

  1. A Mechanical clamps
  2. B Centrifugal force
  3. C Brake-chamber pushrods
  4. D Air pressure

Correct answer: D – Air pressure

Spring brakes use mechanical spring force to apply the parking and emergency brakes. During normal driving, air pressure holds those springs back and keeps the brakes released. If air pressure is removed or lost, the springs apply the brakes. This design is necessary because compressed air can eventually leak away.

Source: Maryland Commercial Driver’s License Manual — § 5.1.14, “Spring Brakes”

Question 5

If air pressure falls far enough, the spring brakes will apply automatically. True or false?

  1. A True
  2. B False

Correct answer: A – True

This statement is true. The Maryland manual states that tractor and straight-truck spring brakes generally apply fully when pressure drops into the 20-to-45 psi range, typically 20 to 30 psi. A driver must not wait for automatic application; the vehicle should be stopped safely when the low-air warning first activates.

Source: Maryland Commercial Driver’s License Manual — § 5.1.14, “Spring Brakes”

Question 6

What should you do when the low-air-pressure warning activates while driving?

  1. A Stop and safely park as soon as possible
  2. B Continue to the next repair facility
  3. C Disable the warning to avoid distraction
  4. D Repeatedly pump the brake pedal

Correct answer: A – Stop and safely park as soon as possible

A low-air warning can indicate that pressure is being lost, possibly because of a leak. Stop and safely park as soon as possible while the brakes can still be controlled. Do not wait for the spring brakes to apply automatically, and do not repeatedly apply and release the pedal because each application consumes stored air.

Source: Maryland Commercial Driver’s License Manual — § 5.4.7, “Low Air Pressure”

More Maryland CDL Practice Tests
Other CDL Endorsements