West Virginia CDL — Air Brakes: Safe Driving Practices Practice Test

Question 1

Four pressure figures come up in Section 5's description of air brake parts: the safety valve's usual opening point, governor cut-out, governor cut-in, and the low air warning mark. Which order runs from highest to lowest?

Accepted Answer

Safety valve opening, governor cut-out, governor cut-in, low air warning — The safety valve normally opens at 150 psi, the governor cuts the compressor out at around 125 psi and back in at around 100 psi, and the low air warning has to show before tank pressure falls under 55 psi. That puts them in this order from top to bottom.

Answer

Governor cut-out, safety valve opening, governor cut-in, low air warning

Answer

Safety valve opening, governor cut-in, governor cut-out, low air warning

Answer

Governor cut-out, governor cut-in, low air warning, safety valve opening

Question 2

The ABS date for air-braked vehicles other than truck tractors covers trucks, buses and trailers. Which other unit does the manual name under that same date?

Accepted Answer

Converter dollies — The March 1, 1998 requirement takes in trucks, buses, trailers and converter dollies. Dollies made from that date on must also have an ABS lamp on the left side.

Answer

Pole trailers only

Answer

Farm tractors

Answer

Tow trucks

Question 3

Which chain of events matches the manual's account of how brake fade develops?

Accepted Answer

Heavy use of the service brakes, then overheating, then chemical changes in the lining and expanding drums, then less friction and weaker contact — The manual traces fade to overusing the service brakes instead of leaning on engine braking. The heat alters the lining so it grips less and swells the drums, so the shoes travel farther and press with less force. Keep it up and the vehicle may not slow or stop at all.

Answer

Low tank pressure, then dragging spring brakes, then cooling drums, then hardened linings

Answer

Wet linings, then rust on the drums, then seized slack adjusters, then locked wheels

Answer

Engine braking, then compressor overload, then an open safety valve, then air loss

Question 4

A pre-1975 truck with a single air system is idling at about 700 rpm. Its pressure takes four minutes to build from 50 to 90 psi. How does that compare with the typical requirement in the manual?

Accepted Answer

It is too slow, because the typical requirement is within three minutes — For single air systems the manual gives a typical requirement of building from 50 to 90 psi within three minutes at an idle of 600 to 900 rpm. Four minutes misses it, and the manual says not to drive until slow buildup is fixed.

Answer

It passes, because single systems are allowed five minutes

Answer

It passes, because only dual systems have a buildup standard

Answer

It is too fast, which points to a stuck governor

Question 5

Which statement about the brake pedal in an air brake system does NOT match the manual?

Accepted Answer

The air used in braking never has to be replaced by the compressor — Every release of the brakes vents some compressed air, which lowers tank pressure, and the compressor has to make that up. That is why needless pumping of the pedal can drain air faster than the compressor restores it.

Answer

Pressing the pedal harder sends more air pressure to the brakes

Answer

Easing up on the pedal cuts the air pressure, which lets the brakes release

Answer

Each release lets a little compressed air leave the system

Question 6

A cab control marked 'normal' and 'slippery' works a front brake limiting valve. On which vehicles does the manual say you might find one?

Accepted Answer

Some older vehicles, made before 1975 — The manual ties the driver-controlled front brake limiting valve to some older vehicles built before 1975, and it says to leave the control in 'normal' so the vehicle keeps its full stopping power. Automatic limiting valves, found on many vehicles, are not driver-controlled.

Answer

All trucks built since 1994

Answer

Only buses with dual parking control valves

Answer

Tractors made from March 1, 1997 onward

Question 7

Which of these is NOT a routine that Section 5 gives the driver?

Accepted Answer

Adjusting automatic slack adjusters by hand before every trip — Automatic slack adjusters have to be checked, but the manual says they should not need manual adjustment outside of brake maintenance and adjuster installation, and that routine hand adjustment will probably wear most of them out early. The other three are regular driver tasks in Section 5.

Answer

Draining manually drained air tanks when each day of driving ends

Answer

Checking the alcohol evaporator's container every day in cold weather

Answer

Checking the compressor's oil level before driving when it carries a separate oil supply

Question 8

What does the manual call the brakes that are used at each wheel of an air-braked vehicle?

Accepted Answer

Foundation brakes — Foundation brakes is the manual's term for the brakes at each wheel. It goes on to describe drum and disc designs under that heading.

Answer

Modulating brakes

Answer

Limiting brakes

Answer

Supply brakes

Question 9

A driver tugs on each slack adjuster during the walk-around with the parking brakes still set and reports that none of them moved. What is wrong with that check?

Accepted Answer

The parking brakes have to be released, with the wheels chocked, so the slack adjusters can be moved — The manual's procedure is to park on level ground, chock the wheels, and let the parking brakes off so that the slack adjusters are free to move. Only then does pulling on them show whether one travels more than about an inch at the push rod.

Answer

Nothing, because no movement means the brakes are in adjustment

Answer

The check only works with the engine at a fast idle

Answer

Slack adjusters are checked only from inside the cab

Question 10

The dash of a truck you have been assigned has one air pressure gauge with two needles in it. What does the manual say that arrangement tells you about the air brake system?

Accepted Answer

It is a dual air brake system, with one needle for each half — Every air-braked vehicle has a supply pressure gauge tied into the air tanks. A dual air brake system has either a separate gauge for each half or one gauge carrying two needles, so two needles point to a dual system.

Answer

One needle shows tank pressure and the other shows oil pressure

Answer

The gauge is faulty and should be replaced

Answer

It is a single system with a spare needle for the trailer

Question 11

Section 5 mentions several model years and dates. Which pairing matches the manual?

Accepted Answer

1994: every vehicle built since then has automatic slack adjusters — The manual says every vehicle built since 1994 has automatic slack adjusters. The year 1975 marks older vehicles with front brake limiting valves and single air systems, while March 1, 1997 and March 1, 1998 are the ABS dates for tractors and for other air-braked vehicles.

Answer

1975: the year ABS became required on truck tractors

Answer

1997: the year front brake limiting valves were introduced

Answer

1998: the last year single air systems were built

Question 12

A driver logs four results from the Step 7 final air brake check on a straight truck with a dual air system and minimum-size tanks. Which entry shows a problem?

Accepted Answer

At operating rpm, pressure took 75 seconds to rise from 85 to 100 psi — A dual system has 45 seconds to climb from 85 psi to 100 psi at operating rpm, so 75 seconds is too slow, and the manual says not to drive until that is fixed. The other entries are inside the limits: under 2 psi released and no more than 3 psi applied for a single vehicle, and a pop-out in the 20 to 45 psi range.

Answer

Brakes released, engine off: lost 1.5 psi in one minute

Answer

Foot brake held down, engine off: lost 2.5 psi in one minute

Answer

Parking brake valve popped out at 30 psi

West Virginia CDL — Air Brakes: Safe Driving Practices practice test

Study questions with answers

1. Four pressure figures come up in Section 5's description of air brake parts: the safety valve's usual opening point, governor cut-out, governor cut-in, and the low air warning mark. Which order runs from highest to lowest?

2. The ABS date for air-braked vehicles other than truck tractors covers trucks, buses and trailers. Which other unit does the manual name under that same date?

3. Which chain of events matches the manual's account of how brake fade develops?

4. A pre-1975 truck with a single air system is idling at about 700 rpm. Its pressure takes four minutes to build from 50 to 90 psi. How does that compare with the typical requirement in the manual?

5. Which statement about the brake pedal in an air brake system does NOT match the manual?

6. A cab control marked 'normal' and 'slippery' works a front brake limiting valve. On which vehicles does the manual say you might find one?

7. Which of these is NOT a routine that Section 5 gives the driver?

8. What does the manual call the brakes that are used at each wheel of an air-braked vehicle?

9. A driver tugs on each slack adjuster during the walk-around with the parking brakes still set and reports that none of them moved. What is wrong with that check?

10. The dash of a truck you have been assigned has one air pressure gauge with two needles in it. What does the manual say that arrangement tells you about the air brake system?

11. Section 5 mentions several model years and dates. Which pairing matches the manual?

12. A driver logs four results from the Step 7 final air brake check on a straight truck with a dual air system and minimum-size tanks. Which entry shows a problem?

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