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📖 Air Brakes Test
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11
How should you check that your service brakes are working properly?
Park on a slight grade, drain off air pressure, set parking brake and check for the movement.
Park on a level ground, chock the wheels, engage the parking brakes when you have the correct amount of air pressure to do so and shut the engine off.
Park on level ground, wait until normal air pressure is reached, release the parking brake and move forward slowly at about 5 mph. Then apply the brakes firmly. ✓ CORRECT
12
A straight truck or bus air brake system should not leak at the rate of more than ____ psi per minute with the engine off and the brakes released.
1.
2 ✓ CORRECT
3.
13
During normal driving, spring brakes are usually held back by:
Bolts or clamps.
Air pressure ✓ CORRECT
Spring pressure.
14
The air compressor stops pumping air at what psi?
100
125 ✓ CORRECT
150
15
The driver must be able to see a low air pressure warning which comes on before the pressure in the service air tanks falls below ____ psi.
40
60 ✓ CORRECT
80
16
Excessive use of the service brakes results in overheating which can lead to:
Proper adjustment of S-cam.
Increase contact between the brake drums and linings.
Expansion of the brake drums. ✓ CORRECT
17
The most common type of foundation brake found on heavy vehicles is the:
Wedge drum.
S-cam drum ✓ CORRECT
Dis
18
If you must make an emergency stop, you should brake so you:
Use the hand brake before the brake pedal.
Can steer and so your vehicle stays in a straight line. ✓ CORRECT
Use the full power of the brakes to lock them.
19
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?
Reduce your speed and drive to the nearest garage for repairs.
Reduce your speed and test the remaining system while underway.
Stop right away and safely park. Continue only after the system is fixed. ✓ CORRECT
20
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?
Reduce your speed and drive to the nearest garage for repairs.
Reduce your speed and test the remaining system while underway.
Stop right away and safely park. Continue only after the system is fixed. ✓ CORRECT