Air Brakes #2
Air Brakes Endorsement Test | Texas 2025 #2 Page 4 of 4
Train for FREE online with our Texas 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 TX 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 . Most heavy-duty vehicles use ____ air brake systems.
Quad
The majority of heavy-duty vehicles are equipped with dual air brake systems.
20 . Brakes may get out of adjustment:
If they get wet.
Brakes can get out of adjustment quickly, especially if they are used to the point of overheating. Brake adjustment should be checked frequently.
21 . How is water and compressor oil removed from the bottom of an air storage tank?
A sponge is used to soak up the water and oil.
Water and compressor oil are removed from air storage tanks through a drain valve. The water and oil can damage the brakes if left to accumulate in the system. Manually operated tanks must be drained every day to remove this build-up.
22 . If your tractor is equipped with ABS but your trailer is not, the ABS:
Will allow others to see when you brake.
In a tractor-trailer combination, if the tractor is equipped with an Anti-Lock Braking System (ABS) but the trailer is not, the ABS will still improve the driver's steering control. The driver should keep an eye on the trailer and let up on the brakes if the trailer begins to swing out.
23 . Friction inside a brake drum is caused when the brake shoes and linings:
Create excess heat.
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.
24 . During a static leakage test, the maximum leakage rate for a triple combination vehicle with air brakes is ____ in a minute.
9 psi
When performing a static leakage test on a triple combination vehicle with air brakes, the leakage rate should be no more than 5 psi in one minute. If air leaks from the air brake system at a quicker rate, the vehicle should not be driven because something likely needs to be repaired.
25 . A visual low pressure warning signal should activate before air pressure drops to a level between:
40 and 60 psi.
