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📖 Air Brakes Test
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21
The air loss rate for a straight truck or bus with the engine off and the brakes on should not be more than:
1 psi in 30 seconds.
2 psi in 45 seconds.
3 psi in one minute ✓ CORRECT
22
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.
50
60 ✓ CORRECT
80
23
The braking power of the spring brakes:
Is not affected by the condition of the service brakes.
Depends on the service brakes being in adjustment. ✓ CORRECT
Increase when the service brakes are hot.
24
The air brake lag distance at 55 mph on dry pavement adds about ___ feet.
12 feet
32 feet ✓ CORRECT
52 feet
25
Total stopping distance for air brakes is longer than that for hydraulic brakes due to ____ distance.
Brake lag ✓ CORRECT
Reaction
Effective braking.
26
It is accepted that too much heat caused by using your brakes too often can also cause:
Modulated control valve to wear out.
Brake linings to split up.
Brake to fade or fail. ✓ CORRECT
27
Repeatedly partially releasing and pressing the brake pedal may result in:
A loss of brake air pressure ✓ CORRECT
A build up of brake air pressure
No change of brake air pressure
28
The brake system that applies and released the brakes when the driver uses the brake pedal is the ____ brake system.
Emergency
Service ✓ CORRECT
Parking
29
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?
1/4 inch
1/2 inch
1 inch ✓ CORRECT
30
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?
1/4 inch
1/2 inch
1 inch ✓ CORRECT