Air Brakes 4

For a bus or straight truck equipped with air brakes, the maximum allowable leakage rate without the foot brake applied is - 4 psi per minute. - 3 psi per minute. - 1 psi per minute. - 2 psi per minute.

- 2 psi per minute.

For a combination vehicle equipped with air brakes, the maximum allowable leakage rate without the foot brake applied is - 1 psi per minute. - 3 psi per minute. - 2 psi per minute. - 4 psi per minute.

- 3 psi per minute.

In a vehicle equipped with air brakes, which of the following activates the stop light switch when you brake? - Spring pressure - Mechanical force - Hydraulic pressure - Air pressure

- Air pressure

Which of the following is the most important thing about hard braking? - Disconnecting the steering axle brakes will help keep your vehicle in a straight line during emergency braking. - Never do it without downshifting first. - Don't lock the wheels for longer than an instant.

- Don't lock the wheels for longer than an instant.

S-cam drum brakes have an S-cam in each brake chamber. Why is it called an "S-cam?" - It is shaped like the letter "S." - It makes the brake shoes move in an S-shaped path. - It is constantly spinning whenever the wheel is spinning.

- It is shaped like the letter "S."

Under ideal conditions, the average driver of a truck or bus equipped with air brakes and traveling at 55 mph would require what stopping distance? - 100 to 250 feet - 300 to 350 feet - More than 400 feet

- More than 400 feet

When can you leave your truck unattended without first applying the parking brakes or chocking the wheels? - If you will only be away from the truck for a few minutes - If you will be conducting your pre-trip inspection - Never

- Never

Which of the following can cause brakes to fade or fail? - Not pressing the brake pedal hard enough - Not taking your foot off the accelerator - Overheating, low air pressure, and not relying on the engine braking effect

- Overheating, low air pressure, and not relying on the engine braking effect

How would you check your truck's slack adjusters? - Park on an incline and see if the vehicle rolls. - Park on level ground, turn off the parking brakes, and pull hard on each slack adjuster. - Park on level ground, turn off the parking brakes, and press the brake pedal.

- Park on level ground, turn off the parking brakes, and pull hard on each slack adjuster.

If oil and water collect in the air tanks, what could happen to the brakes? - The brakes could lock up. - The brakes could fail. - The brakes could heat up.

- The brakes could fail.

What are spring brakes? - They are springs that apply the brakes if air pressure drops too low. - They are the springs on the brake pedal. - They are the CamLaster brakes.

- They are springs that apply the brakes if air pressure drops too low.

What is the purpose of an alcohol evaporator? - So the air tanks won't have to be drained as often - To provide additional windshield washer fluid - To prevent a buildup of ice in the air brake system

- To prevent a buildup of ice in the air brake system

How do you adjust a manual slack adjuster? - Turn the adjusting nut either way until there is less than one inch of play in the slack adjuster. - Turn the adjusting nut to move the end of the slack adjuster toward the air chamber until the nut stops turning. Then turn the nut the other way to move the brake shoes away from the inside of the brake drum. - Turn the adjusting nut to move the end of the slack adjuster away from the air chamber as far as it will go. Then turn the nut the other way to move the brake shoes toward the inside of the brake drum.

- Turn the adjusting nut to move the end of the slack adjuster toward the air chamber until the nut stops turning. Then turn the nut the other way to move the brake shoes away from the inside of the bra

A dual air brake system has two separate brake systems. Which of the following is true? - Typically, there is one brake system for daytime driving and another system for nighttime driving. - Typically, there is one brake system for each side of the vehicle. - Typically, one brake system operates the brakes on the front axle, and the other system operates the brakes on the rear axles.

- Typically, one brake system operates the brakes on the front axle, and the other system operates the brakes on the rear axles.

Are front wheel brakes good under all conditions? - No, so always keep them on the "slippery" setting. - No, the front wheels always skid on ice during braking. - Yes, so keep them on the "normal" setting.

- Yes, so keep them on the "normal" setting.

A converter dolly with antilock brakes (ABS) is required to have - a white lamp on the left side. - a yellow lamp on the left side. - a white lamp on the right side.

- a yellow lamp on the left side.

To test the service brakes, - brake firmly while slowly moving forward. - stop the vehicle, put it in low gear, depress the brake pedal, and then gently pull against the brakes. - brake firmly while slowly moving backward.

- brake firmly while slowly moving forward.

In controlled braking, you - lock the wheels for short periods of time. - brake in a straight line. - can turn sharply.

- brake in a straight line.

Air brakes use _________ to make the brakes work. - hydraulic fluid - natural gas - compressed air

- compressed air

When you press the brake pedal, - compressed air is released from the brake chambers. - compressed air is released from the air tanks. - compressed air enters the brake chambers.

- compressed air enters the brake chambers.

If you need to stop quickly and your vehicle lacks antilock brakes, you can use - (a) the "controlled braking" method. - (b) the "stab braking" method. - either (a) or (b).

- either (a) or (b).

Modern air brake systems are three different systems combined: service brakes, parking brakes, and _______ brakes. - foot - emergency - S-cam

- emergency

As part of your vehicle inspection test, if your vehicle is equipped with air brakes and has a trailer, you will inspect the air connections between the truck or tractor and the trailer. Make sure that the ________ are locked in place and free of damage or air leaks. - glad hands - pins - lug nuts

- glad hands

During your walk-around inspection, check the brake drums to be sure that no cracks are longer than ________ the width of the friction area. - one-half - one-quarter - one-third

- one-half

Before starting down a hill, you should be in the proper gear - so you can coast downhill. - so you only have to apply the brakes just hard enough to feel a definite slowdown. - so you can go through the gears on the way down.

- so you only have to apply the brakes just hard enough to feel a definite slowdown.

To correct a drive-wheel braking skid, you should - stop braking, turn quickly, and countersteer. - brake harder. - brake harder, turn quickly, and countersteer.

- stop braking, turn quickly, and countersteer.

During your final air brake check, if the air pressure does not build up fast enough, - have the problem fixed after your trip is over. - the alcohol evaporator may be low. - the air pressure may drop too low during driving.

- the air pressure may drop too low during driving.

The system that uses parts of the service and parking brake systems to stop the vehicle in a brake system failure is called - the parking brake system. - the service brake system. - the emergency brake system.

- the emergency brake system.

Air tanks must be drained - to tell you how much air is in the tanks. - to drain all the air out of the tanks. - to drain moisture and oil out of the tanks.

- to drain moisture and oil out of the tanks.

To test the static air leakage rate, you should - turn off the engine, release the parking brake, and let the system settle. - charge the air system and leave the engine running. - leave the engine running and release the parking brake.

- turn off the engine, release the parking brake, and let the system settle.