CDL Knowledge & Air Brakes Flashcards
1
Q
2.1
What is the most important reason for doing a vehicle inspection?
A
Safety is the most important reason you inspect your vehicle, safety for yourself and for other drivers.
2
Q
2.1
What things should you check during a trip?
A
- gauges
- tires, wheels, rims
- brakes
- lights, reflectors
- brake and electrical connections to trailer
- trailer coupling devices
- cargo securement devices
3
Q
2.1
Name some key steering parts.
A
- steering wheel
- steering shaft
- gear box
- hydraulic fluid reservoir
- pitman arm
- drag link
- steering knuckle
- spindle
- steering arm
- power steering cylinder
- tie rod
4
Q
2.1
Name some suspension system defects.
A
- cracked or broken spring hangers
- missing of broken leaves in any leaf spring
- broken multi-leaf springs or shifted leaves
- leaking shock absorbers
- cracked, damaged, or missing torque rod/arm, u-bolts, spring hangers
- damaged or leaking air suspension parts
- loose, cracked, broken, or missing frame members
5
Q
2.1
What three kinds of emergency equipment must you have?
A
- Fire extinguisher(s)
- Spare electrical fuses
- Warning devices for parked vehicles (such as reflective triangles)
6
Q
2.1
What is the minimum tread depth for front tires? For other tires?
A
FRONT TIRES= 4/32” tread depth in every major groove
OTHERS= 2/32” tread depth
7
Q
2.1
Name some things you should check on the front of your vehicle during the walk-around inspection.
A
- front axle
- steering system
- windshield
- lights & reflectors
8
Q
2.1
What should wheel bearing seals be checked for?
A
Leaking
9
Q
2.1
How many red reflective triangles should you carry?
A
3
10
Q
2.1
How do you test hydraulic brakes for leaks?
A
Pump the brake pedal 3 times. Then apply firm pressure to the pedal and hold for 5 seconds. The pedal should not move. If it does, there may be a leak or other problem. (This process does not apply to air brakes).
11
Q
2.1
Why put the starter switch key in your pocket during the pre-trip inspection?
A
For your safety.
12
Q
2.2–2.3
Why should you back toward the driver’s side?
A
So you can see better by looking out the side window.
12
Q
2.2–2.3
If stopped on a hill, how can you start moving without rolling back?
A
Put on the parking brake to avoid rolling back. Release it only when you have applied enough engine power to keep from rolling. On equipped tractor trailers you can use the brake hand valve.
12
Q
2.2–2.3
When backing, why is it important to use a helper?
A
There are blind spots you can’t see.
12
Q
2.2–2.3
What’s the most important hand signal that you and the helper should agree on?
A
Stop!
12
Q
2.2–2.3
What are the two special conditions where you should downshift?
A
- before starting down a hill
- before entering a curve
12
Q
2.2–2.3
When should you downshift automatic transmissions?
A
To get greater engine braking when going down grades.
12
Q
2.2–2.3
Retarders keep you from skidding when the road is slippery. True or False?
A
False.
When your drive wheels have poor traction, the retarder may cause them to skid. Turn it off whenever the road is wet, icy, or snowy.
12
Q
2.2–2.3
What are the two ways to know when to shift?
A
- study the vehicle’s operating rpm range and watch the tachometer
- learn what speeds each gear is good for and watch the speedometer
12
Q
2.4–2.6
How far ahead does the manual say you should look while driving?
A
12 to 15 seconds ahead.
At lower speeds that’s about one block. At highway speeds it’s about a quarter mile.
12
Q
2.4–2.6
What are two main things to look for ahead?
A
- Vehicles entering the highway, merging lanes, or turning.
- Brake lights from slowing vehicles.
12
Q
2.4–2.6
What’s your most important way to see the sides and rear of your vehicle?
A
Mirrors — check them regularly.
12
Q
2.4–2.6
What does “communicating” mean in safe driving?
A
Signaling what you intend to do.
13
Q
2.4–2.6
Where should your reflectors be placed when stopped on a divided highway?
A
Place warning devices 10 ft, 100 ft, and 200 ft toward approaching traffic.
14
2.4–2.6
| What three things add up to total stopping distance?
perception distance
+ reaction distance
+ braking distance
= Total Stopping Distance
15
2.4–2.6
| If you go twice as fast, will your stopping distance increase by two or four times?
When you double your speed, the impact is 4 times greater.
16
2.4–2.6
| Empty trucks have the best braking. True or False?
False.
| Empty trucks require greater stopping distances because an empty vehicle has less traction.
17
2.4–2.6
| What is hydroplaning?
Hydroplaning occurs when water collects on the road. The tires lose contact with the road and have no traction. Regain control by releasing the accelerator. Do not brake or oversteer.
18
2.4–2.6
| What is black ice?
A thin layer of ice that is clear enough to see the road through it, making the road look wet.
19
2.4–2.6
| How do you find out how many seconds of following distance space you have?
* 1 second required for each 10 feet of vehicle length (under 40 mph)
* Above 40 mph, an additional second is applied.
20
2.4–2.6
| If you are driving a 30 ft. vehicle at 55 mph, how many seconds of following distance should you allow?
4 seconds.
| 1 second for each 10 feet of vehicle length + 1 second for speed over 40 mph
21
2.4–2.6
| You should increase your following distance if someone is following you too closely. True or False?
True.
Opening up room in front of you will help you to avoid making sudden changes and makes it easier for tailgaters to pass you.
22
2.4–2.6
| If you swing wide to the left before turning right, another driver may try to pass you on the right. True or False?
True.
| Instead, execute a "button-hook turn, waiting to turn until the cab is halfway across the road.
23
2.4–2.6
| What is a hazard?
A hazard is any road condition or other road user that is a possible danger.
24
2.4–2.6
| Why make emergency plans when you see a hazard?
By planning ahead, you decrease your reaction time in the event of an emergency. In this way, you will be a prepared, defensive driver who will improve your own and other's safety.
25
2.9–2.10
| What are some tips to follow so you won't become a distracted driver?
- use electronics hands-free when possible
- pre-program radio stations
- pre-load music
- clear the vehicle of unnecessary objects
- review maps and plan route before driving
- adjust mirrors before driving
- avoid smoking, eating, or drinking while driving
- don't engage in complex or emotional conversations with other occupants
26
2.9–2.10
| How do you use in-vehicle communications equipment cautiously?
- pull off the road in a safe, legal place when receiving a call
- do not place calls while driving
- turn cell phone off until destination is reached
- position phone within easy reach
- pre-program speed dial
- use hands-free
- keep conversations short
- hang up in tricky situations
- do not type or read messages
27
2.9–2.10
| How do you recognize a distracted driver?
- drifting vehicles
- preoccupied with maps, food, cigarettes, phones, etc.
- vehicles traveling at inconsistent speeds
- drivers who appear to be involved in conversations
28
2.9–2.10
| What is the difference between aggressive driving and road rage?
AGGRESSIVE DRIVING: driving a vehicle in a selfish, bold, or pushy manner, without regard for the rights or safety of others.
ROAD RAGE: driving with the intent of doing harm to others or physically assaulting a driver or their vehicle.
29
2.9–2.10
| What should you do when confronted with an aggressive driver?
First, make every attempt to get out of their way. Do not challenge them or attempting to hold your own. Avoid eye contact. Ignore gestures and refuse to react. Report aggressive drivers by providing a description, license number, location, and direction of travel. If they are involved in a crash, stop at a safe distance and report the driving behavior you witnessed to the police when they arrive.
30
2.9–2.10
| What are some things you can do to reduce your stress before and while you drive?
- listen to relaxing music
- don't be distracted
- have a realistic travel time, expecting delays
- if you're going to be late, deal with it, accept it and continue safely.
- give other drivers the benefit of the doubt
- slow down and keep a reasonable following distance
- don't drive slowly in the fast lane
- avoid gestures
- be cautious and courteous
31
2.11–2.14
| You should use low beams whenever you can. True or False?
False.
| Use high beams whenever it is safe and legal in order to increase your vision distance.
32
2.11–2.14
| What should you do before you drive if you're drowsy?
Sleep is the only safe cure to fatigue. Get off the road. If you don't, you risk your life and the lives of others.
33
2.11–2.14
| What effects can wet brakes cause? How can you avoid these problems?
Wet brakes can weaken, apply unevenly, or grab.
Avoid driving through deep puddles or flowing water. If you must, slow down and shift down. Gently put on the brakes (presses linings against brake drums to keep anything from getting in). Increase RPM and cross water while lightly applying brakes. When across, maintain light pressure to heat up and dry out the brakes.
34
2.11–2.14
| You should let air out of hot tires so the pressure goes back to normal. True or False?
False.
| Do not let air out or the pressure will be too low when the tires cool off.
35
2.11–2.14
| You can safely remove the radiator cap as long as the engine isn't overheated. True or False?
False?
| Never remove the radiator cape or any part of the pressurized system until the system has cooled.
36
2.15–2.16
| What factors determine your selection of a "safe" speed when going down a long, steep downgrade?
Select a speed that is not too fast for the:
- total weight of vehicle and cargo
- length of the grade
- steepness of the grade
- road conditions
- weather
37
2.15–2.16
| Why should you be in the proper gear before starting down a hill?
After your speed has already built, you may not be able to downshift at all, or without damage to the transmission.
38
2.15–2.16
| Describe the proper braking technique when going down a long, steep downgrade.
The brakes are only a supplement to engine braking. Apply the brakes just hard enough to feel a definite slowdown. When your speed reduces to 5 mph below your safe speed, release the brakes. When your speed increases to your safe speed, repeat the previous steps.
39
2.15–2.16
| What type of vehicles can get stuck on a railroad highway crossing?
- low slung units (lowboy, car carrier, moving van, possum-belly livestock trailer)
- single-axle trailer pulling a long trailer with its landing gear set to accommodate a tandem-axle tractor.
40
2.15–2.16
| How long does it take for a typical tractor trailer unit to clear a double track?
More than 15 seconds.
41
2.17–2.19
| Stopping is not always the safest thing to do in an emergency. True or False?
True.
When there is not enough room to stop, you may have to steer away from what's ahead. You can always turn faster than you can stop.
42
2.17–2.19
| What are some advantages of going right instead of left around an obstacle?
Moving away from oncoming traffic.
Prevents forcing anyone else into oncoming traffic.
Easier to see and avoid obstacles when they are on your left.
43
2.17–2.19
| What is an "escape ramp"?
An uphill escape route that uses gravity to slow and stop a vehicle, usually installed on long downgrades.
44
2.17–2.19
| If a tire blows out, you should put the brakes on hard to stop quickly. True or False?
False.
Braking when a tire has failed could cause loss of control. Stay off the brake until the vehicle has slowed down. Then brake very gently, pull off the road, and stop.
45
2.17–2.19
| How do you know if your vehicle has antilock brakes?
Tractors, trucks and buses will have yellow ABS malfunction lamps on the instrument panel.
Trailers will have yellow ABS malfunction lamps on the left side, either on the front or rear corner.
On newer vehicles, a system check activates the malfunction lamp at start-up for a bulb check and then goes out quickly.
46
2.17–2.19
| What is the proper braking technique when driving a vehicle with antilock brakes?
Brake normally, i.e. use only the braking force necessary to stop safely and stay in control.
47
2.17–2.19
| How do antilock brakes help you?
ABS helps you avoid wheel lockup and maintain control.
48
2.1
| What is the most important reason for doing a vehicle inspection?
Safety is the most important reason you inspect your vehicle, safety for yourself and for other drivers.
49
2.1
| What things should you check during a trip?
- gauges
- tires, wheels, rims
- brakes
- lights, reflectors
- brake and electrical connections to trailer
- trailer coupling devices
- cargo securement devices
50
2.1
| Name some key steering parts.
- steering wheel
- steering shaft
- gear box
- hydraulic fluid reservoir
- pitman arm
- drag link
- steering knuckle
- spindle
- steering arm
- power steering cylinder
- tie rod
51
2.1
| Name some suspension system defects.
- cracked or broken spring hangers
- missing of broken leaves in any leaf spring
- broken multi-leaf springs of shifted leaves
- leaking shock absorbers
- cracked, damaged, or missing torque rod/arm, u-bolts, spring hangers
- damaged or leaking air suspension parts
- loose, cracked, broken, or missing frame members
52
2.1
| What three kinds of emergency equipment must you have?
1. Fire extinguisher(s)
2. Spare electrical fuses
3. Warning devices for parked vehicles (such as reflective triangles)
53
2.1
| What is the minimum tread depth for front tires? For other tires?
FRONT TIRES= 4/32" tread depth in every major groove
OTHERS= 2/32" tread depth
54
2.1
| Name some things you should check on the front of your vehicle during the walk-around inspection.
- front axle
- steering system
- windshield
- lights & reflectors
55
2.1
| What should wheel bearing seals be checked for?
Leaking
56
2.1
| How many red reflective triangles should you carry?
3
57
2.1
| How do you test hydraulic brakes for leaks?
Pump the brake pedal 3 times. Then apply firm pressure to the pedal and hold for 5 seconds. The pedal should not move. If it does, there may be a leak or other problem. (This process does not apply to air brakes).
58
2.1
| Why put the starter switch key in your pocket during the pre-trip inspection?
For your safety.
59
2.2–2.3
| Why should you back toward the driver's side?
So you can see better by looking out the side window.
60
2.2–2.3
| If stopped on a hill, how can you start moving without rolling back?
Put on the parking brake to avoid rolling back. Release it only when you have applied enough engine power to keep from rolling. On equipped tractor trailers you can use the brake hand valve.
61
2.2–2.3
| When backing, why is it important to use a helper?
There are blind spots you can't see.
62
2.2–2.3
| What's the most important hand signal that you and the helper should agree on?
Stop!
63
2.2–2.3
| What are the two special conditions where you should downshift?
- before starting down a hill
| - before entering a curve
64
2.2–2.3
| When should you downshift automatic transmissions?
To get greater engine braking when going down grades.
65
2.2–2.3
| Retarders keep you from skidding when the road is slippery. True or False?
False.
When your drive wheels have poor traction, the retarder may cause them to skid. Turn it off whenever the road is wet, icy, or snowy.
66
2.2–2.3
| What are the two ways to know when to shift?
- study the vehicle's operating rpm range and watch the tachometer
- learn what speeds each gear is good for and watch the speedometer
67
2.4–2.6
| How far ahead does the manual say you should look while driving?
12 to 15 seconds ahead.
| At lower speeds that's about one block. At highway speeds it's about a quarter mile.
68
2.4–2.6
| What are two main things to look for ahead?
1. Vehicles entering the highway, merging lanes, or turning.
2. Brake lights from slowing vehicles.
69
2.4–2.6
| What's your most important way to see the sides and rear of your vehicle?
Mirrors — check them regularly.
70
2.4–2.6
| What does "communicating" mean in safe driving?
Signaling what you intend to do.
71
2.4–2.6
| Where should your reflectors be placed when stopped on a divided highway?
Place warning devices 10 ft, 100 ft, and 200 ft toward approaching traffic.
72
2.4–2.6
| What three things add up to total stopping distance?
perception distance
+ reaction distance
+ braking distance
= Total Stopping Distance
73
2.4–2.6
| If you go twice as fast, will your stopping distance increase by two or four times?
When you double your speed, the impact is 4 times greater.
74
2.4–2.6
| Empty trucks have the best braking. True or False?
False.
| Empty trucks require greater stopping distances because an empty vehicle has less traction.
75
2.4–2.6
| What is hydroplaning?
Hydroplaning occurs when water collects on the road. The tires lose contact with the road and have no traction. Regain control by releasing the accelerator. Do not brake or oversteer.
76
2.4–2.6
| What is black ice?
A thin layer of ice that is clear enough to see the road through it, making the road look wet.
77
2.4–2.6
| How do you find out how many seconds of following distance space you have?
* 1 second required for each 10 feet of vehicle length (under 40 mph)
* Above 40 mph, an additional second is applied.
78
2.4–2.6
| If you are driving a 30 ft. vehicle at 55 mph, how many seconds of following distance should you allow?
4 seconds.
| 1 second for each 10 feet of vehicle length + 1 second for speed over 40 mph
79
2.4–2.6
| You should increase your following distance if someone is following you too closely. True or False?
True.
Opening up room in front of you will help you to avoid making sudden changes and makes it easier for tailgaters to pass you.
80
2.4–2.6
| If you swing wide to the left before turning right, another driver may try to pass you on the right. True or False?
True.
| Instead, execute a "button-hook turn, waiting to turn until the cab is halfway across the road.
81
2.4–2.6
| What is a hazard?
A hazard is any road condition or other road user that is a possible danger.
82
2.4–2.6
| Why make emergency plans when you see a hazard?
By planning ahead, you decrease your reaction time in the event of an emergency. In this way, you will be a prepared, defensive driver who will improve your own and other's safety.
83
2.9–2.10
| What are some tips to follow so you won't become a distracted driver?
- use electronics hands-free when possible
- pre-program radio stations
- pre-load music
- clear the vehicle of unnecessary objects
- review maps and plan route before driving
- adjust mirrors before driving
- avoid smoking, eating, or drinking while driving
- don't engage in complex or emotional conversations with other occupants
84
2.9–2.10
| How do you use in-vehicle communications equipment cautiously?
- pull off the road in a safe, legal place when receiving a call
- do not place calls while driving
- turn cell phone off until destination is reached
- position phone within easy reach
- pre-program speed dial
- use hands-free
- keep conversations short
- hang up in tricky situations
- do not type or read messages
85
2.9–2.10
| How do you recognize a distracted driver?
- drifting vehicles
- preoccupied with maps, good, cigarettes, phones, etc.
- vehicles traveling at inconsistent speeds
- drivers who appear to be involved in conversations
86
2.9–2.10
| What is the difference between aggressive driving and road rage?
AGGRESSIVE DRIVING: driving a vehicle in a selfish, bold, or pushy manner, without regard for the rights or safety of others.
ROAD RAGE: driving with the intent of doing harm to others or physically assaulting a driver or their vehicle.
87
2.9–2.10
| What should you do when confronted with an aggressive driver?
First, make every attempt to get out of their way. Do not challenge them or attempting to hold your own. Avoid eye contact. Ignore gestures and refuse to react. Report aggressive drivers by providing a description, license number, location, and direction of travel. If they are involved in a crash, stop at a safe distance and report the driving behavior you witnessed to the police when they arrive.
88
2.9–2.10
| What are some things you can do to reduce your stress before and while you drive?
- listen to relaxing music
- don't be distracted
- have a realistic travel time, expecting delays
- if you're going to be late, deal with it, accept it and continue safely.
- give other drivers the benefit of the doubt
- slow down and keep a reasonable following distance
- don't drive slowly in the fast lane
- avoid gestures
- be cautious and courteous
89
2.11–2.14
| You should low beams whenever you can. True or False?
False.
| Use high beams whenever it is safe and legal in order to increase your vision distance.
90
2.11–2.14
| What should you do before you drive if you're drowsy?
Sleep is the only safe cure to fatigue. Get off the road. If you don't, you risk your life and the lives of others.
91
2.11–2.14
| What effects can wet brakes cause? How can you avoid these problems?
Wet brakes can weaken, apply unevenly, or grab.
Avoid driving through deep puddles or flowing water. If you must, slow down and shift down. Gently put on the brakes (presses linings against brake drums to keep anything from getting in). Increase RPM and cross water while lightly applying brakes. When across, maintain light pressure to heat up and dry out the brakes.
92
2.11–2.14
| You should let air out of hot tires so the pressure goes back to normal. True or False?
False.
| Do not let air out or the pressure will be too low when the tires cool off.
93
2.11–2.14
| You can safely remove the radiator cap as long as the engine isn't overheated. True or False?
False?
| Never remove the radiator cape or any part of the pressurized system until the system has cooled.
94
2.15–2.16
| What factors determine your selection of a "safe" speed when going down a long, steep downgrade?
Select a speed that is not too fast for the:
- total weight of vehicle and cargo
- length of the grade
- steepness of the grade
- road conditions
- weather
95
2.15–2.16
| Why should you be in the proper gear before starting down a hill?
After your speed has already built, you may not be able to downshift at all, or without damage to the transmission.
96
2.15–2.16
| Describe the proper braking technique when going down a long, steep downgrade.
The brakes are only a supplement to engine braking. Apply the brakes just hard enough to feel a definite slowdown. When your speed reduces to 5 mph below your safe speed, release the brakes. When your speed increases to your safe speed, repeat the previous steps.
97
2.15–2.16
| What type of vehicles can get stuck on a railroad highway crossing?
- low slung units (lowboy, car carrier, moving van, possum-belly livestock trailer)
- single-axle trailer pulling a long trailer with its landing gear set to accommodate a tandem-axle tractor.
98
2.15–2.16
| How long does it take for a typical tractor trailer unit to clear a double track?
More than 15 seconds.
99
2.17–2.19
| Stopping is not always the safest thing to do in an emergency. True or False?
True.
When there is not enough room to stop, you may have to steer away from what's ahead. You can always turn faster than you can stop.
100
2.17–2.19
| What are some advantages of going right instead of left around an obstacle?
Moving away from oncoming traffic.
Prevents forcing anyone else into oncoming traffic.
Easier to see and avoid obstacles when they are on your left.
101
2.17–2.19
| What is an "escape ramp"?
An uphill escape route that uses gravity to slow and stop a vehicle, usually installed on long downgrades.
102
2.17–2.19
| If a tire blows out, you should put the brakes on hard to stop quickly. True or False?
False.
Braking when a tire has failed could cause loss of control. Stay off the brake until the vehicle has slowed down. Then brake very gently, pull off the road, and stop.
103
2.17–2.19
| How do you know if your vehicle has antilock brakes?
Tractors, trucks and buses will have yellow ABS malfunction lamps on the instrument panel.
Trailers will have yellow ABS malfunction lamps on the left side, either on the front or rear corner.
On newer vehicles, a system check activates the malfunction lamp at start-up for a bulb check and then goes out quickly.
104
2.17–2.19
| What is the proper braking technique when driving a vehicle with antilock brakes?
Brake normally, i.e. use only the braking force necessary to stop safely and stay in control.
105
2.17–2.19
| How do antilock brakes help you?
ABS helps you avoid wheel lockup and maintain control.
106
2.20–2.21
| What are some things to do at an accident scene to prevent another accident?
- protect the area
- notify authorities
- care for the injured
107
2.20–2.21
| Name two causes of tire fires.
1. Under-inflated tires
| 2. Duals that touch
108
2.20–2.21
| What kinds of fires is a B:C extinguisher not good for?
electrical fires and burning liquids
109
2.20–2.21
| When using your extinguisher should you get as close as possible to the fire?
No.
| When using the extinguisher, stay as far away from the fire as possible and aim at the base.
110
2.20–2.21
| Name some causes of vehicle fires.
```
AFTER ACCIDENTS — spilled fuel, improper use of flares
TIRES
ELECTRICAL SYSTEM
FUEL
CARGO
```
111
2.22–2.24
| Common medicines for colds can make you sleepy. True or False?
True.
112
2.22–2.24
| What should you do if you become sleepy while driving?
Stop to sleep.
Take a nap.
Avoid drugs.
Do not rely on tricks to keep you awake. Sleep is the only cure for fatigue.
113
2.22–2.24
| Coffee and a little fresh air will help a drinker sober up. True or False?
False.
The rate at which the liver can process alcohol is fixed, so only time (not coffee, a shower, or fresh air) will sober you up.
114
2.22–2.24
| What is a hazardous materials placard?
signs on the outside of a vehicle that identity the hazard class of the cargo
115
2.22–2.24
| Why are placards used?
- contain the product
- communicate the risk
- ensure safe drivers and equipment
116
2.22–2.24
| What is sleep debt?
the cumulative effect of not getting enough sleep
117
2.22–2.24
| What are the danger signals of drowsy driving?
- your eyes unfocus or close by themselves
- trouble keeping your head up
- can't stop yawning
- wandering, disconnected thoughts
- you don't remember driving the last few miles
- drift between panes, tailgate, or miss traffic signs
- you keep jerking the truck back into the lane
- you have drifted off the road and narrowly missed crashing
118
3
| What four things related to cargo are drivers responsible for?
1. Inspecting the cargo
2. Recognizing overloads and poorly balanced weight
3. Knowing your cargo is secured and does not obscure your front or side views
4. Knowing your cargo does not restrict access to emergency equipment
119
3
| How often must you stop while on the road to check your cargo?
1. Within the first 50 miles
2. After 3 hours or 150 miles
3. Every time you stop for a break
120
3
| How is Gross Combination Weight Rating different from Gross Combination Weight?
GCW is the total weight of a powered unit + trailers + cargo.
GCWR is the maximum GCW specified by the manufacturer.
121
3
| Name two situations where legal maximum weights may not be safe.
- bad weather
| - mountain driving
122
3
| What can happen if you don't have enough weight on the front axle?
it can make the steering axle weight too light to steer safely
123
3
| What's the minimum number of tie-downs for any flatbed load?
There should be at least 1 tie-down for each 10 feet of cargo on any flatbed trailer. No matter how small the cargo is, there should be at least 2 tie-downs securing it.
124
3
| What is the minimum number of tie downs for a 20 ft. load?
2
125
3
| Name the two basic reasons for covering cargo on an open bed.
- to protect people from spilling cargo
| - to protect the cargo from weather
126
3
| What must you check before transporting a sealed load?
that you don't exceed gross weight and axle limits
127
5.1
| Why must air tanks be drained?
Because compressed air usually has some water and compressor oil it, which is bad for the air brake system. The water could freeze and cause brake failure, for example.
128
5.1
| What is a supply pressure gauge used for?
They tell you how much pressure is in the air tanks.
129
5.1
| All vehicles with air brakes must have a low air pressure warning signal. True or False?
True.
A visible warning signal comes on before the air pressure in the tanks falls below 60 psi. The warning is usually a red light, sometimes with a buzzer.
130
5.1
| What are spring brakes?
Used for emergency and parking brakes, spring brakes are held on by mechanical force (because air pressure can leak away). Powerful springs are held back by air pressure. If the air pressure is removed, the brakes are applied. The parking brake control or a leak in the air brakes system will cause the springs to put on the brakes.
131
5.1
| Front wheel brakes are good under all conditions. True or False?
True.
| Make sure the front brake limiting valve (if there is one) is set on "normal" and not "slippery".
132
5.1
| How do you know if your vehicle is equipped with antilock brakes?
Truck tractors with air brakes built on/after March 1, 1997, and other air brake vehicles built on or after March 1, 1998, are required to be equipped with antilock brakes. Check the certification label for the date of manufacture.
133
5.2–5.3
| What are the slack adjusters?
Slack adjusters are used to adjust for wear on s-cam brakes on heavy and medium sized trucks. A lever, connecting the brake chamber push rod with the foundation brake camshaft.
134
5.2–5.3
| How can you check slack adjusters?
Park on level ground and chock the wheels. Release the parking brakes. Use gloves and pull hard on each slack adjuster you can reach. If it moves more than about 1 inch where the push rod attached to it, it probably needs adjustment.
135
5.2–5.3
| How can you test the low pressure warning signal?
1. Shut the engine off when you have enough air pressure so that the low pressure warning is not on.
2. Turn the electrical power on
3. Step on and off the brake pedal to reduce air tank pressure.
The low pressure warning signal must come in before the pressure drops to less than 60 psi in the air tank.
136
5.2–5.3
| How can you check that the spring brakes came on automatically?
Continue to fan off the air pressure (as in the Low Pressure Warning Signal test) by stepping on and off the brake pedal to reduce tank pressure. The parking brake valve should close (pop out) when the air pressure falls to the manufacture e's specification. This will cause the spring brakes to come on.
137
5.2–5.3
| What are the maximum leakage rates?
< 2 psi /min for single vehicles
< 3 psi /min for combination vehicles
< 3 psi /min for single vehicles with brakes applied
< 4 psi /min for combination vehicles with brakes applied
