Air Breaks Flashcards
1
Q
- 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
A
B.2
2
Q
- You should know that your brakes are fading when:
A
b. You have to push the brake pedal harder to control speed on a downgrade.
3
Q
- If the air compressor should develop a leak, what keeps the air in the tanks?
A
c. The one-way check valve.
4
Q
- Oil and water usually collect in compressed air tanks. If you do not have an automatic tank drain, when should you drain the air tanks?
A
a. After every working day.
5
Q
- To check the brake slack on S-cam brakes you should park on:
A
a. Park on level ground, chock the wheel and release the parking brakes.
6
Q
- The application pressure gauge shows how much pressure you have:
A
c. When you are applying to the brakes.
7
Q
- The spring brakes used on the chambers in a straight truck will bring you to a stop when air pressure drops below_ psi.
A
B. 20
8
Q
- The safety valve is set to automatically reduce pressure at ___psi.
A
A. 150
9
Q
- 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.
A
A.45
10
Q
- During normal driving, spring brakes are usually held back by:
a. Air pressure.
A
A. air pressure
11
Q
- The air compressor stops pumping air at what psi?
A
A. 120
12
Q
- The driver must be able to see a warning before the pressure in the service air tanks falls below
A
a.55
13
Q
- The most common type of foundation brake found on heavy vehicles is the:
A
b. S-cam drum.
14
Q
- The braking power of the spring brakes:
A
c. Depends on the service brakes being in adjustment.
15
Q
- The air brake lag distance at 55 mph on dry pavements adds about
feet,
A
a. 32 feet.
16
Q
- Total stopping distance for air brakes is longer than that for hydraulic brakes due to ___distance, To
A
a. Brake lag.
17
Q
- Repeatedly pressing and releasing (fanning) the brake pedal may result in:
A
a. The loss of brake air pressure.
18
Q
- The brake system that applies and releases the brakes when the driver uses the brake pedal is the brake system.
A
b. Service.
19
Q
- A slack adjuster’s free play needs to be adjusted if it is more than about ___how many inches when you pull hard on it?
A
c. 1 inch.
20
Q
- An air brake system is fully charged at what psi?
A
a. 125
21
Q
- The S-cam
A
c. Forces the brake shoes against the inside of the brake drum.
22
Q
- What is the first thing you should do when a low air pressure warning comes on:
A
c. Stop and safely park as soon as possible.
23
Q
- The parking or emergency brake on a heavy vehicle can only be held in position by something that cannot leak away, like:
A
a. Spring pressure
24
Q
- When you apply the brakes, the brake shoes/ lining are pressed against the:
A
a. Brake drum.
25
25. If air pressure is NOT build up fast enough within the correct amount of time:
c. Your air pressure may drop too low during driving
26
26. 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, and then release your brakes.
a.5
27
27. In ideal conditions a truck or bus with an air brake going at 55 mph would require a stopping distance of how many feet?
c. More than 300 feet.
28
28. It is not safe to drive a vehicle that has brake drums with cracks that are no longer than___of the width of the friction area.
a. ½
29
29. Both systems run off of the same air compressor, so if one air compressor malfunctions you will not be able to build or maintain pressure in either system.
a. True
30
30. What are spring brakes?
b. If the air brakes leak down, springs press the brakes on to stop the vehicle.
31
31. When you apply your brakes, the air brake system works with an electric switch, by air pressure, to turn on the brake lights.
b. true
32
32. The service brake applies and releases:
b. The brake when you use the brake pedal during normal driving.
33
33. The governor controls when the air compressor will pump into the air storage tanks.
a. True.
34
34. The storage tanks are used to hold compressed air.
a. True.
35
35. The S-cam forces the brake shoes away from one another and presses them against the inside of the brake drum. It is called the S-cam because:
c. It is shaped like the letter "S".
36
36. What is a dual air brake system?
a. A two-part airbrake system, one operates the front brakes and one operates the back brakes.
37
39. If you are away from your vehicle for only a short time you don't need to use the parking brake.
b. False.
38
37. What are the slack adjusters?
b. It is an adjusting nut on the backside of the brake drum used for adjusting the brakes.
39
38. What are the maximum leakage rates?
b. Less than 2 psi in one minute for single vehicles and less than 3 psi in one minute for combination vehicles.
40
40. The use of brakes on a long steep downgrade is only a supplement to the braking effect of the engine.
a. True.
41
41. Why should you be in the proper gear before starting down a hill?
a. So you only have to apply the brake just hard enough to feel a definite slowdown.
42
42. What is the purpose of an alcohol evaporator?
c. To reduce the risk of ice in the brake valves and other parts in cold weather.
43
43. What is another name for controlled braking?
b. Squeeze braking.
44
44. The brake chamber fills with air pushing the rod out which moves the___
___ which twists the_____
c.Slack adjuster and brake camshaft
45
45. The driver must be able to see a low-pressure warning that comes on before pressure in the service air tank falls below:
a. 60 psi.
46
46. Converter dollies built on or after March 1, 1998, are required to have anti-lock brakes. These dollies will have:
c. A yellow malfunction on the left side of the dolly.
47
47. Controlled braking:
c.Is used to keep a vehicle in a straight line when braking.
48
48. To correct a drive-wheel braking skid, you should
b. Stop braking, turn quickly, and counter steer.
49
49. How do you test the hydraulic brakes for leaks?
b. Pump the brake pedal three times, then apply firm pressure to the pedal and hold for five seconds. The pedal should not move.
50
50. Modern air brake systems are three different systems combined together. They are the service, parking, and the__brakes.
a. Emergency.
