CDL Manual Flashcards
What should be the tread depth of the tires?
4/32” in every major groove in the front tires
2/32” in every major groove in the rear tires
Page 2-1
How many missing leaf springs put a unit out of service?
1/4 of the leaf springs
Page 2-2
When first starting a vehicle, what is an indication tha the ABS isn’t working properly?
The ABS light stays on.
It should turn on and then turn back off shortly after starting the vehicle.
Page 2-4
Air pressure should build from ______ to _____ within _____ minutes
50 to 90 PSI within 3 minutes
Page 2-4
When checking out the vehicle you should build air pressure to governor cut out which is typically between ______ to _______l
120 to 140 PSI
Page 2-4
*The air brake section states that the cut out level is typically about 125 PSI
Page 5-1
What should oil pressure be when idling?
Between 5 and 20 PSI
Page 2-4
What should oil pressure be when operating the vehicle?
Between 35 and 75 PSI
Page 2-4
If you must stop on a road or the shoulder of any road, you must put our your emergency warning devices within how many minutes?
10 minutes.
Page 2-12
If you must stop on or by a one-way or divided highway, where should you place your warning devices?
10 feet, 100 feet and 200 feet towards the approaching traffic
Page 2-12
Perception distance + reaction distance + breaking distance = _________.
Total stopping distance
Page 2-13
The distance your vehicle travels, in ideal conditions; from the time your eyes sees a hazard until your brain recognizes it.
Perception distance
Page 2-13
The distance you will continue to travel, in ideal conditions, before you physically hit the brakes.
Reaction distance
Page 2-14
The distance your vehicle will travel, in ideal conditions, while you are breaking.
Breaking distance
Page 2-14
The total minimum distance your vehicle has traveled, in ideal conditions; with everything considered including perception distance, reaction distance, and breaking distance, until you can bring your vehicle to complete stop.
Total stopping distance.
Page 2-14
How does vehicle weight effect stopping distance?
Empty trucks require greater stopping distance because an empty vehicle has less traction.
The heavier the vehicle, the more work the breaks must do to stop it, and the more heat they absorb.
But the breaks, tires springs and shock absorbers on heavy vehicles are designed to work best when the vehicle is fully loaded.
Page 2-14
Hydroplaning can occur at speeds as low as ____ mph
30 mph
Page 2-15
When the tank pressure falls to the “cut-in” pressure, the governor allows the compressor to start pumping again. “Cut-in” pressure is typically set at what PSI?
Around 100 PSI
Page 5-1
How often should you drain water and oil from the air tanks?
At the end of each day of driving.
Page 5-1
What is the safety valve on air tanks typically set to open at?
150 PSI
Page 5-2
A low air pressure warning signal that you can see must come on before the air pressure in the tanks falls below _____ PSI.
60 PSI
Page 5-3
Tractor and straight truck spring brakes will come on automatically when air pressure drops below what range ?
20 to 45 PSI (typically 20 to 30 PSI)
Page 5-3
Before driving a vehicle with a dual air system, what should you allow time for?
Allow time for the air compressor to build up a minimum of 100 PSI in both the primary and secondary systems.
Page 5-5
When the engine is at operating RPMs, the air pressure should build from _______ to _____ within how many seconds in a dual air system?
85 to 100 in 45 seconds
Page 5-7
The time required for the brakes to work after the brake pedal is pushed.
What type of brakes is this relevant to?
Brake Lag
Air brakes
Page 5-7
What is the formula for total stopping distance?
Perception distance + reaction distance + breaking distance + brake lag (if using air brakes)
Page 5-8
