Air Brakes #1
Air Brakes Endorsement Test | Illinois 2026 #1 Page 4 of 4
Train for FREE online with our Illinois 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 IL 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 . Air tank drains:
Clean the air in the passenger compartment.
In an air brake system, air tanks have drains to remove accumulations of water and compressor oil. Allowing water and oil to accumulate in the system could cause damage to the brakes. Manually operated drains should be used daily.
20 . In a vehicle with dual air brakes, what happens if one system is low on pressure?
The low system will use an auxiliary system to fill the tank.
In a dual air brake system, if one of the air systems gets very low on pressure, either the front or rear brakes will not be operating fully. You should bring your vehicle to a safe stop and have the air system repaired.
21 . You should not use the parking brake:
If your vehicle's other braking systems seem to be working adequately.
A parking brake should not be used if the vehicle's brakes are very hot from use on a steep downgrade or if the brakes are very wet and temperatures are freezing. Using the parking brake when brakes are hot could cause damage to the brakes, and using the brakes when they are wet in freezing weather may cause the brakes to ice up, rendering the vehicle immobile.
22 . In a newer vehicle, you apply the parking brake:
By using a black round knob.
In a newer vehicle with air brakes, the parking brake is controlled by a diamond-shaped yellow knob. The knob is pulled out to apply the parking brakes and pushed in to release them.
23 . How is the parking brake released?
By tapping the accelerator twice
In newer vehicles with air brakes, the parking brakes are controlled by a diamond-shaped yellow knob. Pull the knob out to activate the parking brakes and push it in to release them.
24 . Emergency brakes:
Are optional.
All trucks, truck tractors, and buses must be equipped with emergency brakes and parking brakes. These brakes must be held by mechanical force.
25 . Most heavy-duty vehicles use:
Quadruple air brake systems.
Most heavy-duty vehicles use dual air brake systems, in which there are two separate braking systems operated by a single set of controls. Each system operates the brakes on different axles.
See the exact questions that will be on the 2026 Illinois DMV exam.
99.2% of people who use the cheat sheet pass the FIRST TIME
Lillian MCcranie explains how our CDL study guide was helpful in passing the exam and recommends it to everyone.
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2026 Illinois | Frequently Asked Questions
A CDL Class B license in Illinois allows you to operate single vehicles with a gross vehicle weight rating (GVWR) of 26,001 pounds or more, or any such vehicle towing another not exceeding 10,000 pounds. It also permits the operation of vehicles designed to transport 24 passengers or more, including the driver.
A Class B Commercial Driver's License (CDL) in Illinois allows you to operate single vehicles with a gross vehicle weight rating (GVWR) of 26,001 pounds or more, or a towed vehicle not exceeding 10,000 pounds GVWR. This includes buses, farm labor vehicles, and any vehicles designed to transport 16 to 23 passengers including the driver.
To acquire a Class B CDL license in Illinois, you must be at least 18 years old (21 for interstate driving), possess a valid non-CDL driver's license, pass a vision test, and obtain a medical certificate. You'll also need to pass written knowledge tests and a skills test, which includes a pre-trip vehicle inspection, a basic controls test, and an on-road driving exam.
In Illinois, you must be at least 18 years old to qualify for a Class B Commercial Driver's License (CDL) for intrastate driving (within Illinois only). However, to drive across state lines or to carry hazardous materials, you must be at least 21 years old.
Endorsements for a Class B CDL license in Illinois are not necessary but can be beneficial. They allow you to operate specific types of vehicles. For instance, a passenger endorsement allows you to drive a bus, while a tank vehicle endorsement lets you drive tank trucks. Each endorsement requires passing additional written and/or skills tests.
The Class B CDL skills assessment in Illinois comprises three parts: a pre-trip vehicle inspection to check your understanding of your vehicle and if it's safe to drive, a basic controls test to assess your control over the vehicle, and an on-road driving test to evaluate your driving skills in various road situations and traffic conditions.
Yes, Class B CDL license holders in Illinois are limited to operating vehicles with a Gross Vehicle Weight Rating (GVWR) of 26,001 pounds or more, or towing vehicles not exceeding 10,000 pounds GVWR. They can't operate Class A vehicles unless they have the appropriate Class A endorsement. Also, transporting passengers or hazardous materials requires specific endorsements.
Yes, in Illinois, the written Class B CDL test is available in languages other than English. The Illinois Secretary of State's office offers the test in Spanish, Polish, and some other languages. However, federal regulations require that all CDL holders must be able to read and speak English sufficiently to converse with the general public, understand traffic signs and signals, and respond to official inquiries.
Yes, if you have a disability, you can request accommodations for the Class B CDL written exam in Illinois. You'll need to provide documentation of your disability and specify the type of accommodation needed. It's advised to make this request well in advance of your scheduled test date to give the DMV time to arrange appropriate accommodations.
Yes, if you don't pass the Class B CDL written test in Illinois, you can retake it. However, you must wait until the next business day to do so. If you fail three times, you'll need to start the application process over again. Remember, there may be additional fees for retaking the test.
