Section 2 Flashcards
What tread depth for non steer tires?
And what for steer tires?
4/32” for front tires(steer) in every major groove and 2/32” for other tires
How many missing or broken leaf springs will cause a vehicle to be out of service?
If one-fourth or more are missing
How long should it take for oil pressure to come up to normal pressure?
Should come up to normal within seconds after the engine is started
What is the cutout psi for air brakes?
120-140 psi
What is the idling oil pressure?
5-20 psi
What is the operating oil pressure?
35-75psi
What are the 4 basic types of retarders?
Exhaust, engine, hydraulic, and electric
When turned “on” retarders apply their braking power to the __ wheels when you do what?
Drive wheels whenever you let up on the accelerator pedal all the way
What are the four basic types of retarders?
Exhaust, engine, hydraulic, and electric
When your drive wheels have poor traction, the retarder may cause them to skid. When the road is wet, icy, or snow covered you should?
Turn the retarder off
How far ahead should you look when driving?
12-15 seconds
What are three good rules for using turn signals?
Signal early, signal continuously, and cancel your signal
If you do not wear your seatbelt how many more times likely are you to be fatally injured if you are thrown from the vehicle?
4 times more likely
What is the heavy vehicle formula?
1 second required for every 10 ft of vehicle length at speeds under 40 mph. Above 40mph use the same formula then add one second for the additional speed
Vehicles that are required to stop at railroad crossings with no white painted stop line should stop?
No closer than 15 ft and no further than 50 ft from the nearest rail of the nearest track
What should you make sure of before you try and cross railroad tracks?
Never permit traffic conditions to trap you in a position where you have to stop on the tracks. Be sure you can get all the way across the tracks before you start across.
The braking effect of the engine is greatest when?
It is near the governed rpms and the transmission is in the lower gears
What should you do before starting down a grade?
Shift the transmission into a lower gear before starting down the grade
What should you remember that pertains to avoiding crashes?
Stopping is not always the safest thing to do in an emergency. Remember, you can almost always turn to miss an obstacle more quickly than you can stop.
What should you not do when turning?
Do not apply the brakes when you are turning. It’s very easy to lock your wheels while turning. If that happens you may skid out of control. The more sharply you turn the greater the chances of skid or rollover
What should you do if you have to drive off road in regards to slowing down?
If possible avoid using the brakes until your speed has dropped to about 20 mph
What should you try to do to help you maintain control of your vehicle when you go off road?
You should try to keep one set of wheels on the pavement
What should you do when trying to return to the roadway or paved surface?
Hold the wheel tightly and turn sharply enough to get right back on the road safely. Don’t try to edge gradually back on the road.
Brakes in good condition rarely fail.But what are two most common hydraulic brake failures?
Loss of hydraulic pressure, and brake fade on long hills.
When does ABS activate?
Only when your wheels are about to lock up. It helps keep the vehicle under control during hard braking.
What are most serious skids caused by?
Driving too fast for road conditions
What is by far the most common skid?
The One in which the rear wheels lose traction through excessive braking or acceleration. Skids caused by acceleration usually happen on ice or snow. Braking skids are caused when the rear wheels lock.
What is by far the most common skid?
The One in which the rear wheels lose traction through excessive braking or acceleration. Skids caused by acceleration usually happen on ice or snow.
What causes most front wheel skids?
Driving too fast for conditions causes most front wheel skids. Other causes include lack of tread on the front tires, and cargo loaded so not enough weight is on the front axle
How can you stop a front wheel skid?
The only way to stop a front wheel skid is to let the vehicle slow down. The front end normally in this type of skid tends to go in a straight line regardless of how much you turn the steering wheel
You are more likely to tip over if your load has?
A high center of gravity
Too much weight on the steering axle can cause?
Hard steering
Under loaded front axles can cause?
Can make the steering axle weight too light to steer safely.
Poor traction can be due to ?
Too little weight on the drive axle
Air brakes are really three different braking systems which consist of?
Service brake, parking brake, and emergency brake
How can the air compressor be cooled ?
It can be air cooled or may be cooled by the engine cooling system.
The air compressors oil supply may be from?
It may have its own oil supply or it may be lubricated by engine oil. If it has its own oil supply check the oil level before driving
What is the “cut out” psi
125 psi
What is the “cut in” psi?
100 psi
What are the two types of air tank drain valves?
Manual and automatic
How do manual air tank drain valves work?
By turning a quarter turn or by pulling a cable. You must drain the air tanks yourself.
How do automatic air tanks work?
The water and oil are automatically expelled. They may be equipped with manual draining as well.
