Air Brakes Flashcards
1) Which of the following about antilock braking systems is true?
ABS changes the way you brake in Emergencies.
2) In air brake vehicles, the parking brakes should be used:
Anytime the vehicle is parked.
3)If your antilock braking system is not working, you should:
Drive normally, but get the system serviced soon.
4)
Excessive use of the service brakes results in overheating, which can lead to:
Expansion of the brake drums.
5)
Your truck or bus has a dual air brake system. If a low air pressure warning comes on for only one system
Stop and safely park. Continue only after the system is fixed
6) The air compressor should stop pumping prior to reaching a — psi.
140
7)
The use of air brakes on a downgrade is only a supplement to the:
Braking effect of the engine
8)
Your truck has properly functioning dual air brake system and minimum size air tanks. The air pressure should build from 85-100 psi within
seconds.
45
9)
If your truck or bus has dual parking control valves, you can use pressure from a separate tank to:
Release the spring emergency parking brakes to move a short distance.
10) 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.
5
It is not safe to drive a vehicle that has brake drums (or discs) with cracks or that are thinner than the manufacturer’s specifications, generally this will be __ inch.
1/4
12)
A supply pressure gauge tells you how much pressure is in the:
Air tanks
13)
Air braking takes more time than hydraulic braking because air:
Takes more time to flow through the lines than hydraulic fluid.
14)
During normal driving, spring brakes are usually held back by:
Air pressure
15)
Some air brake systems have an alcohol evaporator. What may happen if you don’t keep the unit filled with alcohol?
Ice may form in the air storage tanks and cause the brakes to fall
16)
The brake system that applies and releases the brakes when the driver uses the brake pedal is the__ system brake
Service
17)
In air brake vehicles, the parking brakes should be used:
Any tme the vehicle is parked
18)
Excessive heat in the brakes can cause the:
Brakes to fade or fall
19) To test air service brakes, you should:
Brake firmly when slowly moving forwards
20)
You should know your brakes are fading when:
You have to push the brake pedal harder to control speed on a downgrade.
21)
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.
2
22) - The braking power of the spring brakes:
Depends on the service brakes being in adjustment.
23)
If your truck has a dual air brake system and one of the systems is low on pressure:
Either the front or rear brakes will not be fully operational.
24)
The parking or emergency brakes of trucks and buses can be legally held on by ___ pressure
Spring pressure
25)
Modern air brake systems are three different systems combined together. They are the service, parking, and the ___ brakes.
Emergency
26)
The air supply pressure gauge shows how much pressure:
Is in the air tanks
27)
If you must make an emergency stop, brake so you:
Can steer and your vehicle stays in a straight line.
28)
If your vehicle has an alcohol evaporator, it is there to:
Reduce the risk of ice in air brake valves in cold weather.
29)
The air brake lag distance at 55 mph on dry pavement adds about ___ feet to your stopping distance.
32
30)
The spring brakes used on tractors and straight trucks will bring your truck to a stop when the air pressure drops
Below ___ psi.
20
31)
When you apply the brakes, the brake shoes/linings are pressed against the:
Brake drum
32)
The use of air brakes on a downgrade is only a supplement to the:
Braking effect of the engine
33)
Why should you drain water from compressed air tanks?
Water can freeze in cold weather and cause brake failure
34)
Repeatedly pressing and releasing (fanning) the brake pedal may result in:
The loss of brake air pressure.
35)
The parking or emergency brakes of trucks and buses can be legally held on by
___ pressure.
Spring
36)
The air compressor governor controls:
When air is pumped into the air storage tanks
37)
The most common type of foundation brake found on heavy vehicies is the:
S-cam drum
38)
You are on a steep downgrade and have reached your “safe” speed of 40 mph. You would apply the service brakes until your speed drops to___ mph
35
39)
You should know brakes are fading when:
You have to push the brake pedal harder to control speed on a downgrade.
40)
Under normal conditions, to engage the parking brake the driver must first:
Let the air out of the spring brakes.
41) If you do not have automatic tank drains, how often should you drain the oil and water from the bottom of compressed air storage air tanks?
At the end of each day for driving.
42)
When is it OK to leave your truck unattended without applying the parking brake or chocking the wheels?
Never
43)
What is the first thing you should do when a low air pressure warning comes on?
Stop and safely park as soon as possible.
44)
The brake pedal in an air brake system:
Controls the air pressure applied to put on the brakes.
45)
Before driving a truck or bus with a dual air brake system, the pressure in each system should be at least_____ psi
100
46)
Moder air brake systems are three different systems combined together. They are the service, parking, and the
____brakes.
Emergency
47) For air brake systems in good condition, the air compressor should start pumping at about ___ psi.
100
48)
How should you check that the spring brakes come on when air pressure in the system drops below a certain
level?
Park on level ground, chock the wheels, release the parking brake when you have enough air pressure, shut the engine off, and repeatedly press and release the brake pedal.
49)
The safety valve is set to automatically reduce pressure at __ psi.
150
50)
Total stopping distance for vehicles with air brakes is longer than that for vehicles with hydraulic brakes due to ___
distance.
Brake lag
51)
Air braking takes more time than hydraulic braking because air:
Takes more time to flow through the lines than hydraulic fluid.
52)
How should you check that your service brakes are working properly?
Wait for normal air pressure, release the parking brake, move the truck forward slowly, and apply the brake firmly using the brake pedal.
53)
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
54)
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.
5
55)
All air brake equipped vehicles have:
An air supply pressure gauge.
56)
The driver must be able to see a warning before air pressure in the service air tanks falls below ___psi.
55
57)
If spring brakes are on, when should you push the brake pedal?
Never
58)
Emergency controlled braking is when you:
Apply the brakes as hard as you can without locking the wheels.
59)
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?
Stop and safely park. Continue only after the system is fixed
60)
When you apply the brakes, the brake shoes/linings re pressed against the:
Brake drum
61)
The most important thing to do when a low air pressure warning comes on is:
Stop and safely park as soon as possible.
62)
If your vehicle has an alcohol evaporator, every day during cold weather you should:
Check and fill the alcohol level.
63)
Total stopping distance for vehicles with air brakes is longer than that for vehicles with hydraulic brakes due to ____distance
Brake lag
64)
When is it OK to leave your truck unattended without applying the parking brake or chocking the wheels?
Never
65)
Some air brake systems have an alcohol evaporator. What may happen if you don’t keep the unit filled with
alcohol?
Ice may form in the air storage tanks and cause the brakes to fail.
66)
The modulating control valve allows you to control the:
Spring brakes
67)
The S-cam:
Forces the brake shoes against the inside of the brake drum
68)
What is emergency stab braking?
Brake hard, release the brakes when the wheels lock, and reapply the brakes when the wheels start rolling.
69)
If your truck or bus has dual parking control valves, you can use pressure from a separate tank to:
Release the spring emergency/parking brakes to move a short distance.
70)
Which of these is not a proper time to apply the parking breaks?
When your brakes are very hot.
71)
The application pressure gauge shows how much air pressure you:
Are applying to the brakes.
72)
The air brake lag distance at 55 mph on dry pavement adds about___
feet to your stopping distance.
32
73)
If pressure does not build up fast enough within the correct amount of time:
Your air pressure may drop too low during driving.
74)
The stop light switch:
Turns on the brake lights to warn drivers behind you.
75)
Why should you drain water from compressed air tanks?
Water can freeze in cold weather and cause brake failure.
76)
You are on a steep downgrade and have reached your “safe” speed of 40 mph. You would apply the service brakes until your speed drops to____
mph.
35
77)
The parking or emergency brake on a heavy vehicle can only be held in position by something that cannot leak away, like:
Spring Pressure.
78) Excessive heat in the brakes can cause the:
Brakes to fade or fail.
79)
To check the brake slack on S-cam brakes, you should park on:
Level ground, chock the wheels, and release the parking brakes.
80)
With air brake vehicles, the parking brakes should be used:
Whenever you leave the vehicle unattended.
81)
A truck with air brakes going 55 mph would require a stopping distance of:
More than 300 feet.
