Air Brakes #1
Air Brakes Endorsement Test | Illinois 2025 #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 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 . 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.
2025 Illinois | Frequently Asked Questions
A CDL Class A license in Illinois is a commercial driver's license that permits the holder to operate any combination of vehicles with a Gross Combination Weight Rating (GCWR) of 26,001 pounds or more, provided the vehicle(s) being towed is/are over 10,000 pounds. This typically includes tractor-trailers and truck and trailer combinations.
With a Class A CDL license in Illinois, you can operate vehicles such as tractor-trailers, truck and trailer combinations, tank vehicles, livestock carriers, and flatbeds. Additionally, it allows the operation of all vehicles covered by Class B and Class C, provided the driver has the appropriate endorsements.
To obtain a Class A CDL license in Illinois, you must be at least 18 years old (21 for interstate driving), possess a valid Illinois driver's license, pass a vision test, and complete a written knowledge exam. You're also required to pass a skills and road test in the type of vehicle you plan to drive. A medical examination report is also typically required.
To qualify for a Class A CDL license in Illinois, you must be at least 18 years old. However, to drive across state lines or to carry hazardous materials, you must be at least 21 years old. Also, you'll need to pass both a written knowledge test and a skills test.
While specific endorsements aren't required for a Class A CDL license in Illinois, additional endorsements can expand the types of vehicles you're allowed to drive or cargo you can transport. For example, an H endorsement permits the transportation of hazardous materials, while a P endorsement allows for the transportation of passengers.
The Class A CDL skills test in Illinois encompasses three parts: a pre-trip vehicle inspection, a basic vehicle control test, and a road test. Examinees must demonstrate their ability to inspect their vehicle, control the vehicle in various situations, and drive safely in normal traffic conditions.
Yes, limitations can be imposed on Class A CDL license holders based on factors like medical conditions or lack of certain skills. For example, a driver may receive a restriction if they can't operate a manual transmission or if they need adaptive equipment to drive. Restrictions are noted on the CDL and must be adhered to while operating commercial vehicles.
Yes, in Illinois, the written Class A CDL test is available in several languages besides English, including Spanish. However, federal law requires that all CDL holders understand English well enough to converse with the general public, understand highway traffic signs and signals, respond to official inquiries, and make entries on reports and records.
Yes, accommodations can be made for the Class A CDL written test if you have a disability. These may include providing the test in an alternate format or allowing additional time. It's important to contact the Illinois Secretary of State's office in advance to discuss your needs and make necessary arrangements.
Yes, you can retake the Class A CDL written test in Illinois if you don't pass on your first attempt. However, you'll need to wait at least 24 hours before retaking the test. Also, keep in mind that each retest may require an additional fee. It's advisable to study thoroughly before attempting the test again.