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Air Brakes Practice Test
Air Brakes Exam
AIR BRAKE KEY FACTS
1. Modern air brake systems combine three systems. They are service, parking and emergency brake systems.
2. The brake pedal applies and releases the service brakes
3. The air compressor governor controls when air is pumped into the air tanks
4. Air tanks with manual drains must be drained at the end of each day
5. Water can freeze in the air brake system causing air brake failure
6. At alcohol evaporator reduces the chance of ice in the air brake valves
7. During the cold weather, alcohol evaporators should be check and filled to the proper level every day
8. The brake pedal controls how much air is supplied to put on the brakes
9. The most common type of foundation brakes on heavy vehicles are S-Cam brakes
10. All vehicles with air brakes must have an air supply pressure gauge
11. An application pressure gauge shows how much air is being applied to the brakes
12. The air tank supply gauge shows how much air is in the air tanks
13. During normal driving spring brakes are held back by air pressure
14. Parking or emergency brakes must be held in position by mechanical pressure, such as spring brakes
15. Spring brakes are dependent on the service brakes being in adjustment
16. On vehicles with dual parking control valves, air pressure from a separate tank can be used to release the emergency and or parking brakes to move a short distance.
17. Anytime a low air pressure device comes on, you should come to a safe stop and continue only when the system has been fixed.
18. When checking the free play of slack adjusters, park on a level ground, chock the wheels, and release the parking brakes.
19. With a straight truck or bus with the engine off and the brakes released. The air brake system should not leak at a rate faster than 2 psi per minute. Add 1 psi for combination vehicles.
20. On a straight truck or bus, with the engine off and the brakes applied the air brake system should not leak at a rate faster than 3 psi per minute. Add 1 psi for combination vehicles.
21. A driver must be able to see a low air pressure warning device come on before air pressure in the service air tank drops below 60 psi
22. When testing the service brakes you should not have delayed stopping action, any unusual feel, or a pull to one side.
23. When making an emergency stop, brake so you can steer and keep your vehicle in a straight line
24. Emergency stab braking is pressing on the brake pedal hard, releasing the brake pedal when the wheels lock up, and when the wheels start rolling repeat the process
25. It takes longer to use air brakes, because air takes more time to flow through the lines than hydraultic fluid does
26. Total stopping distance for air brakes is longer because of brake leg
27. Your brakes are fading when it takes harder brake pressure to control your speed on a downgrade
28. Using a low gear and light steady pedal pressure uses less air than fanning the brake lining will stay cooler and helps keep the vehicles at a constant speed on long downhill grades
29. When a low pressure warning device comes on, you must stop and park safely as soon as possible
30. With air brakes equipped vehicles the parking brakes must be used any time the vehicle is parked. This is regardless of whether the vehicle is attended or not.