Air Brakes #2
Air Brakes Endorsement Test | Missouri 2026 #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 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.
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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.
2026 Missouri | Frequently Asked Questions
To acquire a CDL Passenger endorsement in Missouri, first, you need to have a valid Commercial Driver's License (CDL). Then, you must pass the passenger endorsement knowledge test and a skills test in the type of vehicle you wish to drive. The Missouri Department of Revenue administers these tests. Study materials are available on their website.
To obtain a CDL Passenger license in Missouri, you must be at least 18 years old, possess a valid Missouri CDL, pass the Passenger Transport written test, and pass a skills test in the type of vehicle you will be driving. You must also have a clean driving record and pass a medical examination.
Yes, you need specific training for a CDL Passenger endorsement in Missouri. This includes passing the Passenger Transport written test, and a skills test in a vehicle similar to the one you'll be driving. While not mandatory, it's beneficial to have experience or training driving larger vehicles or buses to help you pass these tests.
Yes, to obtain a CDL Passenger endorsement in Missouri, you must pass the Passenger Transport written test. This exam covers topics such as vehicle inspection, loading and trip start, on the road, after-trip vehicle inspection, prohibited practices, and use of brake-door interlocks. It's an additional requirement to the general CDL tests.
During the CDL Passenger endorsement assessment in Missouri, you will need to demonstrate skills such as pre-trip vehicle inspection, safe driving practices, proper use of mirrors, safe loading and unloading of passengers, responding to emergency situations, and understanding of passenger comfort and safety issues. You'll also need to perform specific maneuvers like turning, backing up, and parking.
No, you cannot legally transport passengers in Missouri without a valid CDL Passenger endorsement. This endorsement is specifically designed to ensure that drivers have the necessary knowledge and skills to safely transport passengers. Driving a commercial vehicle without the proper endorsements can result in fines, penalties, and potentially loss of your CDL.
Yes, you can add the CDL Passenger endorsement to your existing CDL. You don't need a new application for a CDL, but you will need to apply for the endorsement specifically, pass the necessary written test, and pay any associated fees. This process ensures you have the skills and knowledge to safely transport passengers.
Yes, there are specific limitations for drivers with a CDL Passenger endorsement in Missouri. They cannot have more than two moving violations in a three-year period. They must also pass a physical exam every two years, maintain a logbook of their driving hours, and comply with drug and alcohol testing regulations.
Yes, in Missouri, you must be at least 21 years old to drive a commercial vehicle across state lines (interstate) or to carry hazardous materials. However, you can get a CDL Passenger endorsement at 18 years old if you plan to drive within the state lines (intrastate). Note that some employers may have their own age-related policies.
With a CDL Passenger endorsement, you're eligible to operate vehicles such as buses, shuttles, or any vehicle designed to carry 16 or more passengers, including the driver. This also includes school buses if you also carry a School Bus (S) endorsement. Make sure to adhere to the specific regulations for each type of vehicle.