問題一覧
1
How should you check that your service brakes are working properly?
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
2
What is the most common type of foundation found on heavy vehices?
S-cam drum
3
Excessive use of the service brakes result in overheating which can lead to:
Decrease contact between the brake drums and linings
4
The air brake lag distance at 55 mph on dry pavement adds about __ feet
32 feet
5
At what psi is an air brake system is fully charged?
125
6
The air compressor stops pumping air at what psi?
125
7
The driver must be able to see a low air pressure warning which comes on before pressure in the service air tanks below __ psi
60
8
Under normal conditions in order to engage the parking brakes the driver:
Let the air out of air brake system
9
The brake system that applies and releases the brakes when the driver uses the brake pedal is the _____ brake system
Service
10
The S-cam:
Forces the brake shoes against the inside of the brake drum
11
During normal driving, spring brakes are usually held back by:
Airpressure
12
Total stopping distance for air bralkes is longer than for hydraulic bralkes due to ________ distance
brake lag
13
Repeatedly partially releasing and pressing the brake pedal may result in:
A loss of brake air pressure
14
The air loss rate for a straight truck or bus with the engine off and the brakes on should not be more than
3 psi in one minute
15
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.
2
16
Why do you need to drain water from compressed air tanks?
Water can freeze in cold weather and cause brake failure
17
What should you do if your truck or bus has a dual air brake system and a low air pressure warning comes on for only one system?
Stop right away and safely park. Continue only after the system fixed
18
What do all air equipped vehicles have?
A supply pressure gauge A supply pressure gauge
19
If you truck has a properly functioning dual air brake system and minimum size air tanks the air pressure should build up from 85 to 100 psi within how may seconds?
45
20
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?
1inch
21
With air brakes vehicles, the parking brakes should be used:
Whenever you leave the vehicle unattended
22
What will happen if your truclc has a dual air system and one of the systems loses its pressure?
Either the front or back brake will not be fully operational
23
The spring brakes used on the chambers in a straight truck will bring you to a stop when air pressure drops below __ psi
20
24
The braking power of the spring brakes:
Depends on the service brakes being in adjustment