WV · L (restriction removed) Endorsement

West Virginia Air Brakes CDL Practice Test

Below are 25 exam-style questions for the West Virginia Air Brakes CDL knowledge test, modeled on the FMCSA-aligned content used by the West Virginia Division of Motor Vehicles. Try to answer each question on your own before reading the answer key directly under it. The questions and answer choices are shuffled deterministically per state and endorsement, so the order will stay the same on repeat visits — that lets you genuinely measure your improvement.

Heads up: this is a study tool, not a graded exam. Cover the answer with your hand or a sheet of paper for an honest practice run, then re-read the explanations for any questions you missed. Aim for 22 out of 25 or better, three times in a row, before scheduling the real exam.

Question 1 of 25

After releasing the parking brake on a tractor, you should:

A Wait for full system pressure before moving
B Pump the service brake five times
C Drive immediately
D Drain the wet tank

Correct answer: A

Make sure the system reaches at least the cut-out pressure (typically around 120 psi) before driving.

Question 2 of 25

When approaching a long downgrade, you should:

A Coast in neutral
B Test the brakes by lightly applying them at the top
C Skip the brake test
D Test the brakes at the bottom

Correct answer: B

A light brake application at the top tests for pulling or weakness before the descent puts heat into the system.

Question 3 of 25

In a single-vehicle air-brake check with the engine off and brakes released, the maximum allowable air loss is:

A 2 psi per minute
B 5 psi per minute
C 1 psi per minute
D 3 psi per minute

Correct answer: A

Single vehicle, brakes released: not more than 2 psi per minute. Combination vehicle: 3 psi per minute.

Question 4 of 25

Which is true about air storage tanks?

A They never need to be drained
B They must be drained daily to remove water and oil
C They must be drained completely once a year
D They drain themselves automatically in all trucks

Correct answer: B

Most trucks require manual daily draining of each tank. Some have automatic moisture ejectors, but the driver is still responsible.

Question 5 of 25

When you press the brake pedal, brake pressure is:

A Released from the storage tanks
B Received from a separate accumulator
C Created by the pedal mechanically
D Built up from zero by the pedal

Correct answer: A

Pressing the pedal releases stored air from the tanks into the brake chambers; the pedal does not generate pressure itself.

Question 6 of 25

Each axle group on an air-brake-equipped vehicle has its own:

A Set of brake chambers
B Air compressor
C Engine
D Drive shaft

Correct answer: A

Each axle group has its own brake chambers fed by the air system; one compressor supplies all of them.

Question 7 of 25

If the ABS warning light comes on while driving, you should:

A Disconnect the trailer
B Continue driving — you still have normal brakes — and have the system checked at the next opportunity
C Pump the brakes hard
D Immediately stop on the side of the road

Correct answer: B

A failed ABS system reverts to normal braking. Get it repaired but you can complete the trip.

Question 8 of 25

When applying brakes in an emergency with ABS:

A Press as hard as possible and hold
B Pump rapidly
C Stab the brakes
D Release the brakes immediately

Correct answer: A

With ABS, full pressure works because the system pulses for you, allowing maximum braking while preserving steering.

Question 9 of 25

You should not over-tighten a glad-hand because:

A It is bad luck
B It can damage the rubber seals
C It will reduce engine power
D It violates federal weight law

Correct answer: B

Over-tightening crushes the seals. The connection should be firm but not forced.

Question 10 of 25

Air pressure should normally build from 50 to 90 psi within:

A 10 minutes
B Less than 30 seconds
C About 3 minutes in dual systems
D It does not matter

Correct answer: C

Dual air systems should build from 50 to 90 psi within about 3 minutes at idle.

Question 11 of 25

Air pressure builds back up by:

A The compressor pumping air back into the storage tanks
B The driver inflating the tank with a portable pump
C The vehicle's motion
D The brake pedal

Correct answer: A

The engine-driven compressor refills the tanks; the brake pedal only controls release of stored air.

Question 12 of 25

Stopping a vehicle with an air-brake failure can sometimes be done by:

A Using the trailer hand valve, then engine braking, then a runaway ramp if needed
B Putting the transmission in reverse
C Honking
D Coasting in neutral

Correct answer: A

In an air-brake failure, the trailer hand valve can still apply the trailer service brakes, then engine braking and a runaway ramp.

Question 13 of 25

A common cause of an air-brake skid is:

A Driving too fast for conditions
B Both of the above
C Neither of the above
D Locking the wheels by braking too hard

Correct answer: B

Skids result when the wheel locks and the tire loses traction. Speed and over-application are both common contributors.

Question 14 of 25

When applying brakes in an emergency without ABS:

A Pump rapidly and lightly
B Use stab braking — apply hard, release when wheels lock, re-apply
C Use only the parking brake
D Press as hard as possible and hold

Correct answer: B

Stab braking keeps the truck straight in an emergency without ABS. Hard continuous pressure can lock the wheels and cause a jackknife.

Question 15 of 25

During the seven-step air-brake check, the final step is to:

A Check tire pressures
B Drain the wet tank
C Adjust the slack adjusters
D Pull forward and apply the foot brake to test for stopping

Correct answer: D

After all stationary tests, perform a moving brake check at low speed to verify the service brakes stop the vehicle.

Question 16 of 25

The total stopping distance for an air-brake equipped vehicle is:

A Reaction distance + braking distance
B Perception + reaction + brake-lag + braking distance
C Perception + braking distance
D Reaction + braking + brake-lag distance

Correct answer: B

Air brakes add a brake-lag distance — the time from foot-pressure to actual brake application — that hydraulic systems do not have.

Question 17 of 25

Spring-brake pop-out occurs at approximately:

A 0 to 10 psi
B 20 to 45 psi
C 90 to 100 psi
D 60 to 80 psi

Correct answer: B

Pop-out is typically between 20 and 45 psi, varying by manufacturer.

Question 18 of 25

You should test the service brakes by:

A At about 5 mph, applying the brake firmly and feeling for pulling, sticking, or unusual feel
B Driving at 30 mph and slamming on the brakes
C Pumping the brakes
D Listening to the air gauge

Correct answer: A

A low-speed brake test catches sticking, pulling, or weak brakes before you build up speed.

Question 19 of 25

A driver should never:

A Use the trailer hand valve as a parking brake
B Test the parking brake
C Make pre-trip inspections
D Drain the wet tank

Correct answer: A

The trailer hand valve is not a parking device — see the trailer-hand-valve question. Always set the trailer parking brakes.

Question 20 of 25

When a vehicle is hooked to a trailer, the air system must include:

A Only an electrical connector
B Only a safety chain
C One additional reservoir for the trailer brakes
D Service line and emergency line, with glad-hand connectors

Correct answer: D

Air goes through service and emergency (supply) lines to the trailer, with glad-hand connectors and color-coded couplers.

Question 21 of 25

In a combination vehicle, with the brakes applied and the engine off, the maximum allowable air loss is:

A 4 psi per minute
B 5 psi per minute
C 2 psi per minute
D 3 psi per minute

Correct answer: A

Combination vehicle, brakes applied: 4 psi per minute. Single vehicle, brakes applied: 3 psi per minute.

Question 22 of 25

Cross-leakage between primary and secondary brake systems is:

A A normal feature
B A serious defect that can prevent backup braking
C Caused by overuse
D Required by federal law

Correct answer: B

Each circuit must remain independent so a failure in one still leaves the other working.

Question 23 of 25

A foot-valve pressure gauge reading lower than expected during a brake application could indicate:

A A leak or restriction
B A worn seat belt
C Normal operation
D A new compressor

Correct answer: A

Low pressure during application means the system isn't delivering full braking force — investigate.

Question 24 of 25

You should test the parking brake by:

A Driving over a curb
B Setting the parking brake, releasing the service brake, and gently trying to move the vehicle
C Doing nothing — the dashboard light is enough
D Pressing the service brake while parked

Correct answer: B

Apply throttle gently in low gear; if the truck moves, the parking brake is not holding.

Question 25 of 25

You should NOT drain the wet tank when:

A There is no situation in which draining is wrong
B You are about to begin a trip
C It is full of moisture
D The vehicle is in motion

Correct answer: A

Daily draining is a routine task; there is no situation where draining is unsafe (other than while driving).

Study tips for the West Virginia Air Brakes exam

The Air Brakes portion of the West Virginia CDL exam is graded out of the bank of questions the West Virginia Division of Motor Vehicles draws from each year. While the exact bank is not published, every question is sourced from the Air Brakes chapter of the West Virginia CDL handbook, which itself is derived from the FMCSA Model Commercial Driver's License Manual. That means studying our practice tests, reading the corresponding handbook chapter, and re-reading the parts you got wrong is genuinely the most efficient route to a first-time pass.

Most successful applicants follow a simple cycle: take the practice test cold, write down every question you missed, open the matching chapter of the official West Virginia handbook, re-read the section that contains the right answer, then re-take the practice test 24 to 48 hours later. The 24-hour delay matters — sleep is when your brain commits new information to long-term memory, and CDL knowledge questions reward that kind of consolidated learning rather than cramming.

Pay particular attention to questions that include qualifier words like always, never, only, primary, or most. CDL test writers love to flip the right answer with a single qualifier. When two answer choices look almost identical, pay attention to the verb (is it must, should, or may?) and to any numbers (14 days, 100 air miles, 8 hours, 70/8 split). On endorsement tests in particular, watch for trick framing where a true statement about a different endorsement is offered as the "correct" answer to a question that is actually about Air Brakes.

Test-day logistics matter too. Bring photo ID, your Social Security card or birth certificate, your medical examiner's certificate (DOT card), and proof of state residency if you haven't already submitted those documents. The West Virginia Division of Motor Vehicles will not let you sit for the knowledge exam without your documentation, and most offices charge an additional fee for re-attempts. Arrive early — the wait at most CDL testing offices runs 30 to 60 minutes — and silence your phone before the exam begins.

Finally, keep your General Knowledge fundamentals sharp even when you're focused on the Air Brakes exam. Many states administer multiple knowledge tests in a single sitting, and questions on weight definitions (GVWR, GCWR, GAWR), stopping distance, and the pre-trip inspection routine show up across endorsements. If you're unsure on the basics, sit a fresh West Virginia General Knowledge practice test before scheduling the real exam.

Next steps

Missed more than four questions? Re-read the Air Brakes study guide and the matching chapter in the official West Virginia CDL handbook. Then come back and re-take the test. Once you can score 22 of 25 or higher on three runs in a row, you're in good shape to schedule the real exam at your local West Virginia Division of Motor Vehicles office.

Already comfortable with this endorsement? Drill another: WV General Knowledge · WV Combination Vehicles · WV Hazardous Materials · WV Passenger · WV School Bus · WV Tank Vehicle · WV Doubles / Triples

New to the CDL process in West Virginia? Read How to apply for a CDL in West Virginia for the document checklist and step-by-step timeline.