CDL Air Brake Practice Test 2025-2026 most recent version Comprehensive questions and verified answers accurate solutions Already graded A+ Get it 100% correct A straight truck or bus air brake system should not leak at a rate of more than __ psi per minute with the engine off and the brake released.
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d. 4 - CORRECT ANSWER: c. 3
Air braking takes more time than hydraulic because air:
- Brakes use different brake drums.
- Takes more time to flow through the lines than hydraulic fluid.
- Brakes require heavier return springs.
- Is always leaking through airline fittings. - CORRECT ANSWER: b. Takes more time
to flow through the lines than hydraulic fluid.
All air brake equipped vehicles have:
- At least one brake heater.
- A hydraulic system, in case the air system fails.
- A supply pressure gauge.
d. An air usage gauge. - CORRECT ANSWER: c. A supply pressure gauge.
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During normal driving, spring brakes are usually held back by:
- Bolts
- Air Pressure
- Spring pressure
d. Centrifugal force - CORRECT ANSWER: b. Air Pressure
For emergency stab braking, you should:
- Pump the brake pedal rapidly and lightly.
- Press on the brake pedal as hard as you can, release the brakes when the wheels
- Brake hard until the wheels lock, then get off the brakes for as much time as the
- Press hard on the brake pedal and apply full hand valve until you stop. - CORRECT
lock, and when the wheels start rolling put on the brakes fully again.
wheels were locked.
ANSWER: b. Press on the brake pedal as hard as you can, release the brakes when
the wheels lock, and when the wheels start rolling put on the brakes fully again.
If you do not have automatic tank drains, how often should you drain the oil and water from the bottom of compressed air storage tanks?
- After every four hours of service.
- At the end of each day of driving.
- Once a week.
d. Every other week. - CORRECT ANSWER: b. At the end of each day of driving.
If you must make an emergency stop, brake so you:
- Can steer hard while braking hard.
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