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40 Cards in this Set
- Front
- Back
The air compressor governor controls:
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When air is pumped into air tanks.
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What is emergency stab braking?
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Brake as hard as you can, release the brakes when the wheels lock, and reapply the brakes again when the wheels start rolling. |
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To check the free play of manual slack adjusters on S-cam brakes, you should park on level ground:
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Chock the wheels and turn off parking brakes. |
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Which of these is NOT a proper time to apply the parking brakes? |
When your brakes are very hot. |
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Excessive use of the service brakes results in overheating, which can lead to: |
Expansion of the brake drums. |
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The driver must be able to see a warning before air pressure in the service air tanks falls below___ psi:
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55 |
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The proper method of braking when going down long and/or steep grades, after selecting the proper gear, is to brake until your speed is about___ miles per hour below your "safe" speed, then release your brakes. |
5
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If your truck or bus has dual parking control valves, you can use pressure from a separate tank to: |
Release spring emergency/parking brakes to move short distance. |
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The brake pedal in an air brake system:
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Controls the air pressure applied to put on the brakes. |
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If air pressure does NOT build up to normal within the correct amount of time: |
Your air pressure may drop too low during driving. |
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Under normal conditions, to engage the parking brakes the driver must first: |
Let the air out of the air brake system |
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Some air brake systems have an alcohol evaporator. What may happen if you don't keep the unit filled with alcohol?
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Ice may form in the air storage tanks and cause the brakes to fail |
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The parking or emergency brake on a heavy vehicle can only be held in position by something that cannot leak away, like: |
Spring pressure. |
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How should you check that your service brakes are working properly?
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Wait for normal air pressure, release the parking brake, move the truck forward slowly, and apply the brake pedal firmly. |
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Total stopping distance for vehicles with air brakes is longer than that for vehicles with hydraulic brakes due to___ distance. |
Brake lag. |
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Your truck or bus has a dual air brake system. If a low air pressure warning comes on for only one system, what should you do?
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Stop and safely park. Continue only after the system is fixed. |
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If you must make an emergency stop, you should brake so you: |
Can steer and your vehicle stays in a straight line. |
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The brake system that applies and releases the brakes when the driver uses the brake pedal is the ___ brake system. |
Service. |
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The air brake system for a straight truck or bus should not leak at a rate of more than ___ psi per minute with the engine OFF and the brakes released. |
2 |
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Before driving a truck or bus with a dual air brake system, the pressure in each system should be at least ___ psi |
100 |
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In air brake vehicles, the parking brakes should be used: |
Any time the vehicle is parked. |
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The most common type of foundation brake found on heavy vehicles is the: |
S-cam drum |
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Repeatedly pressing and releasing (fanning) the brake pedal may result in: |
The loss of brake air pressure. |
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If the spring brakes are on, when should you push the brake pedal? |
Never. |
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How should you check that the trailer brakes come on when air pressure in the system drops below a certain level? |
Chock the wheels, apply the parking brake, shut the engine off, and pump the brake pedal to reduce air tank pressure. |
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You should know your brakes are fading when: |
You have to push the brake pedal harder to control speed on a downgrade. |
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The air loss rate for a straight truck or bus with the engine off and the brakes on should not be more than: |
3 psi in one minute. |
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The brake pedal in an air brake system:
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Controls the air pressure applied to put on the brakes.
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Truck and bus parking or emergency brakes must be held on by: |
Mechanical force. |
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The air brake lag distance at 55 mph on dry pavement adds about ___ feet to your stopping distance.
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32. |
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What is emergency controlled braking? |
You apply the brakes as hard as you can without locking the wheels. |
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The driver must be able to see a low air pressure warning which comes on before pressure in the service air tanks falls below ___ psi. |
55 |
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For air brake systems in good conditions, the air compressor should start pumping at about ___ psi
|
85 |
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If your truck has a dual air system and one of the systems is low on pressure:
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Either the front or rear brakes will not be fully operational.
|
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The air compressor governor controls:
|
When air is pumped into the air tanks.
|
|
If your truck or bus has dual parking control valves, you can use pressure from a separate tank to: |
Release spring emergency/parking brakes to move a short distance. |
|
If your truck's air compressor has its own oil supply, when should you first check the oil level? |
Before driving. |
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The stop light switch: |
Turns on the brake lights to warn drivers behind you. |
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You are on a steep downgrade and have reached your "safe" speed of 40 mph. You would apply the service brakes until your speed drops to ___ mph. |
35
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The braking power of the spring brakes: |
Depends on the service brakes being in adjustment. |