Air Brakes #1
Air Brakes Endorsement Test | Oregon 2025 #1 Page 3 of 4
Train for FREE online with our Oregon 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 OR 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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13 . 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.
14 . During an applied leakage test, what is the maximum leakage rate that is safe for a single vehicle with air brakes?
It is important to know the maximum air loss rate that is safe for your specific vehicle. A single vehicle with air brakes should have a leakage rate no higher than 3 psi in a minute during an applied leakage test.
15 . Foundation brakes are used:
Foundation brakes are used on each wheel of a CMV. The most common type of foundation brake is the s-cam drum brake.
16 . What can happen if parking brakes are used in very wet weather with temperatures below freezing?
The brakes may become too smooth to be used.
Parking brakes should not be used in very wet weather when temperatures are below freezing. The brakes could become frozen in place, making it impossible to move the vehicle.
17 . When only the tractor is equipped with an Anti-Lock Braking System (ABS):
The brakes will become more sensitive.
If a tractor is equipped with an Anti-Lock Braking System (ABS) but the trailer is not, the risk of jackknifing will be reduced and the driver should still be able to maintain steering control. If only the trailer is equipped with ABS, it is less likely that the trailer will swing out to one side.
18 . To inspect slack adjusters on S-cam brakes, you need to:
Chock the wheels and disengage the parking brake.
