1.
WHICH BRAKE SYSTEM APPLIES AND RELEASES THE BRAKES WHEN THE DRIVER USES THE BRAKE PEDAL?
Correct Answer
C. DRUM
Explanation
The correct answer is DRUM. The drum brake system applies and releases the brakes when the driver uses the brake pedal. In a drum brake system, when the driver presses the brake pedal, hydraulic pressure is applied to the wheel cylinders, causing the brake shoes to press against the inner surface of the brake drum. This friction between the shoes and drum slows down or stops the rotation of the wheel, allowing the vehicle to come to a halt. When the driver releases the brake pedal, the hydraulic pressure is released, and the brake shoes retract from the drum, allowing the wheel to rotate freely again.
2.
MODERN AIR BRAKES ARE A COMBINATION OF SERVICE, PARKING, AND WHAT OTHER BRAKE SYSTEM?
Correct Answer
B. EMERGENCY
Explanation
Modern air brakes are a combination of service, parking, and emergency brake systems. The emergency brake system is an important component of air brakes as it provides an additional level of safety in case of a failure in the service brake system. It is designed to be used in emergency situations where immediate and maximum braking force is required to bring the vehicle to a stop. The emergency brake system operates independently of the service brake system and is activated by a separate control mechanism, such as a hand lever or foot pedal.
3.
WHAT DOES THE AIR COMPRESSOR GOVERN CONTROL?
Correct Answer
D. AIR PUMPED INTO THE AIR TANKS
Explanation
The air compressor governs control over the air pumped into the air tanks. This means that the air compressor is responsible for supplying compressed air to the air tanks, which are then used to operate various systems in the vehicle, such as the brakes. The air pressure applied to the brakes and the release of pressure in the brake chamber are outcomes of the air pumped into the air tanks by the compressor. Therefore, the correct answer is "AIR PUMPED INTO THE AIR TANKS."
4.
WHY SHOULD YOU DRAIN WATER FROM COMPRESSED AIR TANKS?
Correct Answer
A. WATER CAN FREEZE AND CAUSE BRAKE FAILURE
Explanation
Draining water from compressed air tanks is necessary because water can freeze and cause brake failure. When water freezes, it can block the air passages and prevent proper air flow, leading to a loss of braking power. By draining the water regularly, the risk of freezing and subsequent brake failure can be minimized, ensuring the safe operation of the brakes.
5.
WHAT IS THE PURPOSE OF AN ALCOHOL EVAPORATOR?
Correct Answer
C. REDUCES THE RISK OF ICE IN AIR BRAKE VALVES
Explanation
An alcohol evaporator is used to reduce the risk of ice formation in air brake valves. When air brakes are used in cold weather, moisture in the compressed air can condense and freeze, leading to ice formation in the valves. This can hinder the proper functioning of the brakes and pose a safety risk. The alcohol evaporator helps prevent this by introducing a small amount of alcohol into the air system, which lowers the freezing point of the moisture and prevents ice formation.
6.
FOR VEHICLES WITH AN ALCOHOL EVAPORATOR, WHAT SHOULD YOU DO EVERY DAY DURING COLD WEATHER?
Correct Answer
C. CHECK AND FILL THE ALCOHOL LEVEL
Explanation
During cold weather, vehicles with an alcohol evaporator need to have their alcohol level checked and filled every day. This is because cold temperatures can cause the alcohol to evaporate more quickly, leading to a decrease in the alcohol level. By regularly checking and filling the alcohol level, the vehicle ensures that it has enough alcohol to effectively mix with the fuel and prevent fuel line freezing.
7.
WHAT DOES THE BRAKE PEDAL DO IN AN AIR BRAKE SYSTEM?
Correct Answer
B. CONTROLS THE AIR PRESSURE APPLIED TO THE BRAKES
Explanation
The brake pedal in an air brake system controls the air pressure applied to the brakes. When the driver presses the brake pedal, it activates the air compressor, which increases the air pressure in the system. This increased air pressure is then used to apply the brakes, causing the vehicle to slow down or stop. Without the brake pedal, the driver would not be able to control the amount of air pressure applied to the brakes, making it difficult to safely operate the vehicle.
8.
THE MOST COMMON TYPE OF FOUNDATION BRAKE IS THE:
Correct Answer
B. S-CAM DRUM BRAKE
Explanation
The most common type of foundation brake is the S-CAM drum brake. S-CAM stands for "slack adjuster camshaft," which is a mechanism that applies force to the brake shoes. Drum brakes use brake shoes that press against the inside of a drum to create friction and slow down or stop the vehicle. The S-CAM drum brake is widely used in commercial vehicles because of its reliability and durability. It is a cost-effective option that provides efficient braking performance.
9.
ALL AIR BRAKE EQUIPPED VEHICLES HAVE:
Correct Answer
A. AIR SUPPLY PRESSURE GAUGE
Explanation
All air brake equipped vehicles have an air supply pressure gauge. This gauge is used to monitor the pressure of the compressed air in the air brake system. It is important to have this gauge as it allows the driver to ensure that there is sufficient air pressure for the brakes to function properly. If the air pressure drops below a certain level, it can indicate a problem with the system that needs to be addressed. Therefore, the presence of an air supply pressure gauge is essential for the safe operation of air brake equipped vehicles.
10.
WHAT DOES THE AIR SUPPLY PRESSURE GAUGE INDICATE?
Correct Answer
C. THE PRESSURE IN THE AIR TANK
Explanation
The air supply pressure gauge indicates the pressure in the air tank. This gauge is used to monitor the amount of pressure in the tank, which is important for the proper functioning of the hydraulic system. It allows the operator to ensure that there is sufficient pressure for the system to operate effectively.
11.
THE APPLICATION PRESSURE GAUGE SHOWS:
Correct Answer
B. HOW MUCH AIR PRESSURE YOU ARE APPLYING TO THE BRAKES
Explanation
The application pressure gauge shows how much air pressure you are applying to the brakes. This means that it measures the amount of force or pressure that is being exerted on the brake system when the brake pedal is pressed. By monitoring this gauge, you can determine the level of pressure being applied and adjust it accordingly to ensure effective braking.
12.
THE DRIVER MUST BE ABLE TO SEE THE AIR PRESSURE WARNING LIGHT COME ON BEFORE THE PRESSURE GETS BELOW:
Correct Answer
C. 60 PSI
Explanation
The driver must be able to see the air pressure warning light come on before the pressure gets below 60 PSI. This is because the warning light serves as an indicator to alert the driver when the air pressure in the system is reaching a critical level. By being able to see the warning light at 60 PSI, the driver can take necessary actions to prevent any potential issues or accidents caused by low air pressure in the system.
13.
DURING NORMAL DRIVING, SPRING BRAKES ARE USUALLY HELD BACK BY:
Correct Answer
C. AIR PRESSURE
Explanation
During normal driving, spring brakes are usually held back by air pressure. Spring brakes are a safety feature in air brake systems that engage automatically when there is a loss of air pressure in the system. The air pressure is used to hold the spring brakes in the released position, allowing the vehicle to move. If there is a loss of air pressure, such as in the event of a leak or failure in the air brake system, the spring brakes will engage and apply the brakes to prevent the vehicle from moving.
14.
IF THERE IS A LEAK IN THE AIR BRAKE SYSTEM, THE PARKING OR EMERGENCY
Correct Answer
A. SPRING BRAKE
Explanation
If there is a leak in the air brake system, the parking or emergency spring brake will be affected. The spring brake is designed to engage automatically when the air pressure drops below a certain level, ensuring that the vehicle remains stationary and preventing it from rolling away. Therefore, if there is a leak in the air brake system, the spring brake will activate and hold the vehicle in place. This is important for ensuring the safety of the vehicle and preventing accidents.
15.
WHAT AFFECTS THE POWER OF THE SPRING BRAKES?
Correct Answer
B. THE ADJUSTEMENT OF THE SPRING BRAKES INSURES THE POWER
Explanation
The adjustment of the spring brakes ensures the power because if the spring brakes are not properly adjusted, they may not engage fully or may not release properly, resulting in reduced braking power. Proper adjustment ensures that the spring brakes are able to effectively engage and hold the vehicle in place when the parking brakes are applied. It also ensures that the spring brakes release smoothly when the parking brake is released, allowing for proper movement of the vehicle. Therefore, the adjustment of the spring brakes is crucial in maintaining their power and effectiveness.
16.
WHAT IS THE PURPOSE OF DUAL PARKING CONTROL VALVES?
Correct Answer
D. TO RELEASE THE SPRING BRAKE IN AN EMERGENCY
Explanation
Dual parking control valves are used to release the spring brake in an emergency. The spring brake is a safety feature in air brake systems that applies the brakes when there is a loss of air pressure. In an emergency situation, such as a sudden loss of air pressure, the dual parking control valves allow the driver to manually release the spring brake, enabling the vehicle to move and preventing it from being stuck or immobilized. This feature is crucial for ensuring the safety and maneuverability of the vehicle in emergency situations.
17.
FOR A DUAL AIR BRAKE EQUIPPED VEHICLE, WHAT SHOULD YOU DO IF THE SECONDARY SYSTEM FAILS?
Correct Answer
D. BRING THE VEHICLE TO A SAFE STOP, AND GET THE SYSTEM FIXED
Explanation
If the secondary system of a dual air brake equipped vehicle fails, the best course of action is to bring the vehicle to a safe stop and get the system fixed. Continuing to drive with a faulty brake system can be extremely dangerous and increase the risk of accidents. It is important to prioritize safety and address the issue promptly by stopping the vehicle and seeking repairs.
18.
HOW DO YOU CHECK THE FREE PLAY OF MANUAL SLACK ADJUSTERS ON S-CAM BRAKES?
Correct Answer
A. PARK ON LEVEL GROUND, CHOCK THE WHEELS, TURN OFF PARKING BRAKES
Explanation
To check the free play of manual slack adjusters on S-cam brakes, you should park on level ground, chock the wheels, and turn off the parking brakes. This ensures that the vehicle is stable and the wheels are secure. By turning off the parking brakes, you can release any tension or pressure on the slack adjusters, allowing you to accurately measure the free play.
19.
WHEN TESTING THE LOW PRESSURE WARNING SYSTEM, YOU SHOULD BUILD UP YOUR AIR PRESSURE, AND THEN:
Correct Answer
B. TURN ELECTRICAL POWER ON AND PUMP BRAKE WITH ENGINE OFF
Explanation
When testing the low-pressure warning system, it is important to turn the electrical power on and pump the brake with the engine off. This is because the low-pressure warning system relies on the electrical power to detect any issues with the air pressure in the system. By pumping the brake with the engine off, it allows the system to accurately measure the air pressure and determine if the warning system is functioning properly.
20.
WHEN CHECKING THAT THE SPRING BRAKES COME ONE AUTOMATICALLY, THE PARKING BRAKE KNOB SHOULD POP OUT WHEN:
Correct Answer
B. THE AIR PRESSURE FALLS TO BETWEEN 20-40 PSI
Explanation
The correct answer is "THE AIR PRESSURE FALLS TO BETWEEN 20-40 PSI." When checking that the spring brakes come on automatically, the parking brake knob should pop out when the air pressure falls to between 20-40 PSI. This is because the spring brakes are designed to engage when there is a significant drop in air pressure, indicating a potential loss of braking power. Therefore, when the air pressure reaches the specified range, the parking brake knob should pop out, ensuring that the spring brakes are engaged and the vehicle is safely secured.
21.
A STRAIGHT TRUCK AIR BRAKE SYSTEM WITH THE ENGINE OFF AND THE SERVICE BRAKE RELEASED, SHOULD NOT LEAK AT A RATE GREATER THAN:
Correct Answer
B. 2 PSI PER MINUTE
Explanation
A straight truck air brake system should not leak at a rate greater than 2 PSI per minute when the engine is off and the service brake is released. This is important because excessive air leaks can cause a loss of braking power and potentially lead to accidents. Monitoring the rate of air leakage is crucial for maintaining the efficiency and safety of the brake system.
22.
A BUS AIR BRAKE SYSTEM, WITH THE ENGINE OFF AND THE BRAKE PEDAL ON, SHOULD NOT LEAK AT A RATE GREATER THAN:
Correct Answer
D. PSI IN ONE MINUTE
Explanation
The correct answer is 2 PSI in one minute. This means that a bus air brake system, with the engine off and the brake pedal on, should not have a leak that causes the pressure to drop more than 2 PSI in one minute. This is an important safety measure to ensure that the brakes are functioning properly and can be relied upon in case of an emergency. A leak rate greater than 2 PSI in one minute could indicate a problem with the brake system that needs to be addressed.
23.
WHEN TESTING THE SERVICE BRAKES, YOU HAVE A PROBLEM WHEN:
Correct Answer
D. ALL OF THE ABOVE
Explanation
When testing the service brakes, having a delayed stopping action, the vehicle pulling to one side, or experiencing an unusual feel are all indicators of a problem. These issues suggest that the brakes are not functioning properly and may require maintenance or repair. It is important to address these problems promptly to ensure the safety and efficiency of the braking system.
24.
HOW SHOULD YOU BRAKE IN AN EMERGENCY STOP?
Correct Answer
B. BRAKE SO THAT YOU CAN STEER AND STAY IN A STRAIGHT LINE
Explanation
In an emergency stop, it is important to brake in a way that allows you to steer and maintain a straight line. This means applying the brakes firmly but not so hard that you lose control of the vehicle. By braking in this manner, you can avoid skidding or veering off the road, increasing your chances of safely stopping the vehicle.
25.
WHAT IS EMERGENCY STAB BRAKING?
Correct Answer
C. REPEATEDLY BRAKING UNTIL THE WHEELS LICK, THEN RELEASING PRESSURE
26.
WHY DOES AIR BRAKING TAKE MORE TIME THAN HYDRAULIC BRAKING?
Correct Answer
C. IT TAKES AIR TIME TO FLOW THROUGH THE LINES
Explanation
Air braking takes more time than hydraulic braking because it takes time for air to flow through the lines. In an air brake system, when the driver applies the brakes, air pressure is used to activate the brakes. This air pressure needs time to flow through the lines and reach the brake drums, causing a delay in the braking action. On the other hand, hydraulic braking systems use fluid to transmit pressure instantly, resulting in quicker response times.
27.
TOTAL STOPPING DISTANCE FOR AIR BRAKES IS LONGER THAN FOR HYDRAULIC BRAKES DUE TO:
Correct Answer
C. BRAKE LAG DISTANCE
Explanation
The correct answer is brake lag distance. Brake lag distance refers to the time it takes for the air brakes to engage and apply pressure to the brake pads, resulting in a delay in the stopping process. This delay is longer compared to hydraulic brakes, which have a more immediate response. Therefore, the total stopping distance for air brakes is longer due to the additional time it takes for the brakes to fully engage.
28.
HOW CAN YOU TELL IF YOUR BRAKES ARE FADING ON A LONG DOWNGRADE?
Correct Answer
B. YOU HAVE TO PUSH HARDER TO CONTROL YOUR SPEED
Explanation
On a long downgrade, if your brakes are fading, you will have to push harder on the brake pedal to control your speed. This is because fading brakes lose their effectiveness and require more force to slow down or stop the vehicle. The other options, such as brake lag distance being shorter and brakes not cooling sufficiently between applications, do not accurately describe the signs of fading brakes.
29.
WHY IS SHORTER, LIGHT BRAKE PEDAL PRESSURE USED ON LONG DOWNHILL GRADES INSTEAD ON ON-OFF BRAKING?
Correct Answer
A. LIGHT PRESSURE DOESN'T HEAT UP THE BRAKES AS FAST
Explanation
When braking on long downhill grades, using shorter, light brake pedal pressure instead of on-off braking helps to prevent the brakes from heating up too quickly. Continuous heavy braking can generate a lot of heat, which can lead to brake fade or failure. By applying light pressure steadily, the brakes have a chance to cool down between applications, reducing the risk of overheating and maintaining their effectiveness. Therefore, the correct answer is that light pressure doesn't heat up the brakes as fast.
30.
THE MOST IMPORTANT THING TO DO WHEN THE LOW AIR PRESSURE WARNING COMES ON IS TO:
Correct Answer
A. STOP AND PARK AS SOON AS POSSIBLE
Explanation
When the low air pressure warning comes on, the most important thing to do is to stop and park as soon as possible. This is because low air pressure can affect the braking system of the vehicle, making it unsafe to continue driving. By stopping and parking, the driver can assess the situation and take appropriate measures to address the low air pressure issue before continuing their journey. Adjusting the brake pedal, using the parking or emergency brake, or tapping the air pressure gauge may not effectively resolve the problem and could potentially lead to further complications.
31.
IN AN AIR BRAKE VEHICLE, WHEN DO YOU USE THE APRKING BRAKES?
Correct Answer
C. ANY TIME YOU PARK
Explanation
The correct answer is ANY TIME YOU PARK. In an air brake vehicle, the parking brakes should be used every time you park the vehicle, regardless of whether it is during a pre or post-trip inspection, in an emergency, or when parking on downgrades with the service brake. The parking brakes are designed to hold the vehicle in place when it is parked and should always be engaged to ensure the safety of the vehicle and those around it.
32.
HOW OFTEN SHOULD YOU DRAIN YOUR AIR TANKS IF IT IS NOT DONE AUTOMATICALLY IN YOUR VEHICLE?
Correct Answer
A. AT THE END OF EACH DAY OF DRIVING
Explanation
To ensure proper functioning of the air tanks in a vehicle, it is important to drain them regularly. Draining the air tanks at the end of each day of driving helps remove any accumulated moisture or contaminants, preventing potential damage to the tanks and the overall air system. This practice also helps maintain optimal air pressure and ensures the safety and efficiency of the vehicle's braking system. Regular draining of air tanks is especially crucial if it is not done automatically in the vehicle.
33.
Which axle or axles does the dual air brake system operate?
Correct Answer
C. All axles
Explanation
The dual air brake system operates on all axles. This means that both the front and rear axles of a vehicle are equipped with air brakes that are controlled by the dual air brake system. By operating on all axles, this system ensures effective braking and control of the vehicle, enhancing safety on the road.