Air Brakes #2
Air Brakes Endorsement Test | Missouri 2025 #2 Page 4 of 4
Train for FREE online with our Missouri 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 MO Class A/Class B driver license in 2025, 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.
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19 . Friction in an S-cam brake is caused when the brake shoes and linings:
Friction inside a brake drum is caused when the brake shoes and linings push against the inside of the drum. The friction in the drums will slow and stop the vehicle.
20 . Manual air tank drains should be:
Compressed air in an air brake system usually contains a certain amount of water and compressor oil. The water and oil can damage the brakes if left to accumulate in the system. Manually operated air tank drains must be opened daily to remove this build-up.
21 . A wig wag is:
Vehicles with air brakes are required to be equipped with a low pressure warning device. A wig wag is a type of low air pressure warning device. This device drops a mechanical arm into the driver's view if the pressure in the tanks drops to a level between 55 and 75 psi.
22 . Some water and compressor oil is usually found in the compressed air within an air brake system. The water and compressor oil:
If water and compressor oil are left to build up in an air brake system, the system can be damaged. Air storage tanks are equipped with drains to allow this accumulation to be removed. Manually controlled drains should be operated at the end of each day of driving.
23 . What is brake lag?
Because air takes time to flow through the air lines to the brakes, air brakes cannot begin working instantly. There is often a brake lag of at least one-half of a second between the moment the brake pedal is pressed and the moment the brakes begin to work.
24 . What does an air compressor do in an air brake system?
In an air brake system, the air compressor pumps air into the air storage tanks. The air compressor is controlled by the air compressor governor.
25 . Air storage tanks:
In an air brake system, the air storage tanks hold compressed air to be used by the brakes. The number and size of air tanks varies among vehicles.
2025 Missouri | Frequently Asked Questions
A CDL Class B license in Missouri permits the holder to operate single vehicles with a gross vehicle weight rating (GVWR) of 26,001 or more pounds, or any such vehicle towing another not in excess of 10,000 pounds. This covers vehicles like buses, dump trucks, and straight trucks. You must pass a knowledge test and skills test to obtain this license.
A Class B CDL license in Missouri allows the holder to operate single vehicles with a gross vehicle weight rating (GVWR) of 26,001 pounds or more, or a vehicle towing another not exceeding 10,000 pounds. This includes large buses, segmented buses, dump trucks, straight trucks, delivery trucks, and utility trucks. It does not include tractor-trailers.
To acquire a Class B CDL license in Missouri, you must be at least 18 years old (21 for interstate driving), possess a valid non-commercial driver's license, pass a vision test, and obtain a medical certificate. You'll also need to pass a written knowledge test and a skills test, which includes a pre-trip vehicle inspection, basic vehicle control, and on-road driving.
In Missouri, you must be at least 18 years old to qualify for a Class B Commercial Driver's License (CDL) for intrastate driving (within Missouri borders). However, if you plan to drive interstate (across state or country borders), you must be at least 21 years old.
Specific endorsements aren't necessary for a Class B CDL license, but they can expand your driving capabilities. Endorsements like passenger and school bus, tank vehicle, double/triple trailers, and hazardous materials can be added after passing additional written and skills tests. Each endorsement may have additional requirements. Check with your local DMV for specifics.
The Class B CDL skills assessment in Missouri includes three main parts: a pre-trip vehicle inspection to check your understanding of your vehicle and its safety, a basic vehicle control test to assess your ability to maneuver and control the vehicle, and an on-road driving test to evaluate your driving skills in various traffic situations and road conditions.
Yes, Class B CDL license holders in Missouri are limited to driving single vehicles with a gross vehicle weight rating (GVWR) of 26,001 pounds or more, or a towing vehicle not exceeding 10,000 pounds GVWR. They're also restricted from driving a Class A vehicle unless they have the appropriate endorsement. Other restrictions may apply based on endorsements and medical conditions.
Yes, it is possible. In Missouri, the written Class B CDL test can be taken in English or Spanish. However, Federal regulations require that anyone applying for a commercial driver's license must be able to read and understand English well enough to converse with the general public, understand highway signs and signals, respond to official inquiries and make entries on reports and records.
Yes, test accommodations can be requested for the Class B CDL written exam in Missouri due to disability. These may include accessibility features or alternative testing formats. It's important to make the request at the time of scheduling your exam and provide appropriate documentation to support your request. Contact your local DMV for specific procedures.
Yes, you can retake the Class B CDL written test in Missouri if you fail on your first attempt. Applicants must wait at least one day before retesting. There is a $25 retest fee for each attempt. If you fail three times, you must wait 30 days before your next attempt. It's recommended to study thoroughly to ensure success on the next try.