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51 Cards in this Set
- Front
- Back
1. Emergency stab braking is when you |
Brake as hard as you can, release the brakes when the wheels lock, and put on the brakes again when the wheels start rolling |
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2. If air pressure does NOT build up to normal within the correct amount of time, then |
Your air pressure may drop too low during driving, requiring an emergency stop. |
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3. Which of these is NOT a proper time to apply the parking brakes? |
If the brakes are very hot (e.g. after just coming down a steep grade) |
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4. Excessive use of the service brakes results in overheating which can lead to |
Expansion of the brake drums |
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5. The proper method of braking when going down long and or steep grades, after selecting the proper grade, is to brake until your speed is about ___ miles per hour below your "safe" speed, then release your brakes. |
Five |
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6. Under normal conditions, in order to engage the parking brakes, the driver must first |
Let the air out of the air brake system. |
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7. Total stopping distance for air brakes is longer than that for hydraulic brakes due to ___ distance. |
Brake lag |
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8. If you must make and emergency stop, you should brake so you |
Can steer Nd so your vehicle stays in a straight line |
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9. If your truck or bus has dual parking control valves, you can use pressure from a separate tank to |
Release the spring emergency/parking brakes to move a short distance |
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10. To check the free play of manuel slack adjusters in S-cam brakes, you should park on |
Level ground, chock the wheels and turn off the parking brakes. |
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11. A straight truck or bus air brake system should not leak at a rate of more than ___ per minute with the engine off and the brakes released. |
2 PSI |
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12. The air compressor governor controls: When the air is ___ into the air tanks |
Pumped |
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13. The parking or emergency brake of trucks and buses can only be legally held on by |
Spring pressure |
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14. The brake pedal in an air brake system |
Controls the air pressure applied to put on the brakes. |
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15. Some air brake systems have an alcohol evaporator. What may happen if you don't keep the unit filled with alcohol? |
Ice may form in the air storage tanks Nd cause the brakes to fail |
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16. 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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17. Before driving a truck or bus with a dual air brake system, the pressure in each system should be at least ___ |
100 PSI |
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18. Your truck or bus has a dual air brake system. If a low pressure warning comes on for only one system, what should you do? |
Stop right away and safely park. Continue only after the system is fixed |
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19. How should you check that your service brakes are working properly? |
Wait for normal air pressure, release the parking brake, move the truck forward slowly and apply the brakes firmly using the brake pedal. |
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20. You should know that your brakes are fading when: |
You have to push harder on the brake pedal to control your speed on a downgrade. |
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21. If the spring brakes are on, when should you push the brake pedal? |
NEVER |
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22. The driver must be able to see a low pressure warning which comes on before pressure in the service air tanks falls below ___ PSI. |
55 |
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23. The most common type of foundation brake found on heavy vehicles is the |
S-CAM drum |
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24. If your truck has a dual air system and one of these systems is low on pressure |
Either the front or rear brakes will not be fully operational. |
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25. In air brake vehicles, the parking brakes should be used |
Any time the vehicle is parked |
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26. The stop light switch |
Turns on the brake lights to warn drives drivers behind you. |
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27. For air brake systems in good condition, the air compressor should start pumping at about ___ PSI |
100 |
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28. The air loss 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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29. The braking power of the spring brakes |
Depends on the service brakes being in adjustment |
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30. How should you check that the spring brakes comes on when the 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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31. If you are driving down a steep downgrade and have reached your "safe" speed of 40 mph, you would apply the service brakes until your speed drops ___ mph. |
35 |
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32. The air brake lag distance at 55 mph on dry pavement adds about ___ feet to your stopping distance |
32 |
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33. Repeatedly pressing and releasing (fanning) the brake pedal may result in |
The loss of brake air pressure. |
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34. Emergency controlled braking is when you |
Apply the brake as hard as you can without locking the wheels. |
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35. If your truck's air compressor has its own oil supply, when should you check the oil level? |
Before driving. |
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36. If your vehicle has an alcohol evaporator, it is there to |
Reduce the risk of ice in air brake valves in cold weather. |
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37. The application pressure gauge shows how much air pressure you |
Are applying to the brakes. |
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38. The most important thing to do when a low air pressure warning comes on is |
Stop and safely park as soon as possible. |
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39. Your vehicle has a dual air brake system. If a low pressure warning comes on for the secondary system, you should |
Bring the vehicle to a safe stop and continue only when the system is fixed |
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40. If your truck has a properly functioning dual air brake system and minimum size air tanks, the air pressure should build from 85 to 100 PSI within ___ seconds. |
45 |
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41. When the brakes are applied, the brake shoes ( or linings) are pressed against the |
Brake drum or disc |
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42. Under ideal conditions, a truck with air brakes going 55 mph would require stopping distance of |
More than 30 feet |
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43. The use of air brakes on a long and/or steep downgrade under normal conditions is only a supplement to |
The braking effect of the engine |
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44. The air compressor should stop pumping at about ___ PSI |
125 |
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45. All air brake equipped vehicles have |
An air supply pressure gauge |
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46. During normal driving, sping brakes are usually held back by |
Air pressure. |
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47. The safety valve is usually set to automatically reduce pressure at |
150 PSI |
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48. Air brakes take more time than hydraulic braking because air |
Takes more time to flow through the lines than hydraulic |
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49. Why drain water from compressed air tanks? |
Water can freeze in cold weather and cause brake failure. |
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50. It is not safe to drive a vehicle that has brake drums (or discs) with cracks or that are thinner than manufacturer's specifications. Generally this will be |
1/4 inch. |
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51. The modulating valve allows you to control the |
Amount of pressure in the brake system. |