Hi there smart drivers. Rick with Smart Drive Test talking today about chapter 5,
section 4 of the New York State CDL manual, which talks about air brakes and it is the
final section of a three-part series, where I've gone over the manual and
giving you clarification & more information about air brakes. This last
section is about braking with ABS— anti-lock braking systems—most of the
vehicles in this day and age—all the ones that you're going to encounter—are all
going to be equipped with anti-lock braking systems.
There is some information about braking with vehicles that don't have ABS:
stab braking, emergency braking - the ways to get out of an emergency
situation. Braking and steering around an emergency situation - steering is much
faster.
I'll explain that later in more detail as well.
Parking brakes -
one of the transitions for people upgrading to a higher licenses is that you
have to use the parking brakes every time you get out of the vehicle.
Unlike our personal vehicles that have automatic transmissions and most of
the time we don't use the parking brake, in big trucks & buses
you have to use the parking brakes every time you leave the driver's seat.
So know that you have to use the parking brakes. As well, downhill braking - brake
fade!
What happens if the low air warning comes on. We're going to talk about all of that.
Section 5.4 of the New York State CDL commercial driver's manual and get you
through - get you a CDL license - get you going up and down the road.
Get you a job & get your making more money. We'll be right back to talk to you about that.
[OPENING CREDITS & MUSIC]
Hi there smart drivers. Rick with Smart Drive Test talking to you today about chapter 5,
section 4 of the New York State CDL manual. This last section is a the last
section of a three-part series. We're going to talk to you about that in more
detail right now.
Page 5-10 - normal stops: push down on the brake pedal come to make a general stop. Just
before the vehicle comes to a complete stop, release the brake pedal & reapply and
come to a complete stop. The reason you want to do that is to avoid a jolt, as
the vehicle comes to a stop.
Because what happens is that the unit is two pieces: 1) the body and 2) the chassis. When you
brake,—if you hold the brakes on
until the vehicle comes to a complete stop,
when it comes to a complete stop, the body will slingshot back over the
chassis. Novice drivers are especially good at that - first couple of lessons you
need to wear your neck brace!
However for your purposes brake early, come to a complete stop, just before the
vehicle comes to a complete stop,
release the brakes, allow the body to settle back over the chassis and then
reapply the brakes.
Braking with anti-lock brakes: in an emergency situation,
hold the brakes - hard, firm. You may have to post off the steering wheel to hold
the brakes down. Shutter, noise, grinding push back, all of that is normal with ABS
brakes.
Look in the direction that you want the vehicle to go. The reason for anti-lock
brakes is so that the tires do not lock up and you maintain control of the vehicle
and are able to steer in the direction that you want to go in an emergency
situation.
The other thing about an emergency situation - make sure you have your
seatbelt on. Your seatbelt not only protects you in the event of a crash, but
protects you
by keeping you in the seat. If you're in the seat you can control the vehicle; if
you're not in the seat - tough to control the vehicle. So make sure you wear your
seat belt in combination with ABS brakes in an emergency situation.
Page 5-11 stab braking: push the brakes to the point of lockup,
release the brakes and let the wheels roll again. Get control of the vehicle
again,
and then steer in the direction you want to go and reapply the brakes. An
emergency situation - there are two ways out of an emergency situation:
1) breaking or 2)steering. However for steering, you have to have some place to
drive into, so it's important when you drive to keep space around your vehicle
because you need space to drive into. Now steering out of an emergency situation is
much faster than braking;
however, in a braking situation you want to do stab braking or what's called
threshold breaking. We bring the vehicle to almost lock up—
most vehicles in this day and age are all going to be equipped with ABS brakes—
so it's you're not going to be able -
you're not going to be able to bring the vehicle to lock up in terms of braking.
But it is the fastest way to get it stopped.
So we already talked about ABS brakes, the use of ABS brakes and getting it
stopped in an emergency situation. If your vehicle doesn't have ABS brakes,
you're going to do stab braking where you bring it to full lock up,
release the brakes, reapply and bring the vehicle to a stop. Hopefully before you
get into a crash with another vehicle or a fixed object.
The other thing about braking in emergency situations or an emergency braking
situation in particularly in rain or ice - if you have slippery conditions on
the roadway is you need to be watching in the mirrors in a combination vehicle
to make sure that trailer isn't coming around. Because if the trailer begins to
jackknife,
you're going to have to make adjustments in either your steering,
you're braking, or your acceleration in order to try and get that trailer to
straighten out again.
So be mindful in emergency situations in a tractor-trailer unit that you keep
the unit going straight down the road.
The other thing about emergency situations in a combination vehicle is
to try and brake when the truck and trailer is in a straight line. if you're
in a curve and you brake
it's a good chance - there's a much higher chance that that unit is
going to jackknife on you. Know that as weight increases and as speed increases
for the purposes of a commercial vehicle, that your stopping distance is going to
be much greater. If you see the graph on page 5-12, a tractor-trailer unit requires
another third the distance to stop as opposed to a car.
Therefore you're going to increase your following distance so you have more room
to stop and bring your vehicle to a safe stop in the event of an emergency.
Following distance in a large commercial vehicles is approximately five seconds.
Watch the video here on following distance. I'll put a card up here for you -
that way you'll know how to measure out following distance and keep a proper
distance for the purposes of a road test when
getting your CDL license.
Brake fade and failure on page 5-12. Again I'll put a card up here for you for the
complete video on brake fade and that will explain to you what brake fade is.
And in this day and age, there is really no reason that you should have brake fade
in a large commercial vehicle.
They're all equipped with engine brakes and engine brake technology is really
great.
As long as you get in the right gear before you go down over the hill
you should be good. Remember the saying about braking down hill in a
large commercial vehicle: you can go down the hill a thousand times too slow; the
one time you go too fast,
unfortunately you're not going to recover from that! So always get into the
right gear, until you get to know that hill, until you get to know your vehicle,
do you want to try and go a little bit faster.
Page 5-13: proper braking technique - we already talked about that - hard,
short, intermittent brake applications. Right gear, engine brake on full, bring
the speed down five miles per hour. If you do in fact need to use the service
brakes, let it run back up,
bring it down five miles an hour. That is the proper braking technique in this
day and age. However if you get in the right gear— five low in a 13- or 18-
speed, which is the most common transmissions. You come down over the
hill,
if it's less than double digits on the grade signs, the Jake (engine brake) will hold you back
in a fully loaded semi trailer - 80,000 pounds.
You're not going to have any problems - Jake brakes—engine brake technology
is very effective in this day and age.
If the low air warning comes on for any reason, get the vehicle pulled ove to the
side of road as quickly as possible in a safe location. And I do stress safe
location. There are lots of places along the interstates that are not safe and
you do not want to be standing out there!
So try and get into a pullout or someplace that you can squeeze over and whatnot.
Don't try and stop in the middle of a bridge. It's just too dangerous. Vehicles are
traveling too fast. So try and get it over to a safe location before you bring
the vehicle to a stop.
Parking brakes: this just goes without saying in a large vehicle. For those of
us who are veterans-in terms of driving trucks and buses and other vehicles
equipped with air brakes-not putting the parking brakes on when you stop the
vehicle
it's just - it's it's a little bit foreign to us. But for new drivers getting in
vehicles, I have seen them not put the parking brakes on when they parked the
vehicle. You always have to put the parking brakes on. And just as an aside,
it's a good idea to get in the habit of using parking brakes in your personal
vehicles as well. However we know as driving instructors and experts, that 85
to 90 percent of people driving automatic transmission vehicles do not
use the parking brake.
There's a pin in that transmission, when you put it into park and it's really
hard on that pin when you don't use the parking brake.
So on big trucks, every time you park the unit make sure you put the parking
brakes on - pul the buttons out on the dash. The yellow— the parking brake control valve—
it's the yellow four side button you can see here in the image. The trailer supply
valve—eight-sided, octagon button—controls air supply to the trailer, and
consequently applies the trailer brakes.
Parking brake - apply them!
I'm in the habit, I don't put the trailer brakes on on a semi-truck because i did
have the trailer brakes freeze on at one point. They got really wet and I parked the
trailer,
dump the air and came back and the trailer brakes were frozen. Essentially
what happens is the shoes freeze to the drum.
So I'm just in the habit of holding my thumb on the red button, and I pull out the
truck parking brakes and that is sufficient to hold the unit. For the purposes a
road test, however, make sure you pull them both out though.
When you get working, get in that habit of not putting on the trailer brakes.
There's enough heat generated in around the truck the axles and differentials
and whatnot, that the brakes on the truck are unlikely going to freeze on unless
you're working in sub-zero temperatures. And the manual also says if you're
descending steep downgrade and you pull in somewhere to park,
don't put the parking brakes - on use wheel chocks instead. And I don't really
see that happening. There aren't too many places that you're not going to be that don't have
a distance of driving where the brakes are going to cool off before you
actually get there to park. So I don't see that as a problem. So when you're
doing a pre-trip inspection and whatnot, make sure you get the wheel chocks on.
Make sure as well that you put the parking brakes on every time you park.
Questions on page 5-14. Why should you be in the proper gear before starting down
the hill?
I've been in trucks with students who tried to get a gear coming down over the
hill and end up going down the hill and NOT in gear!
Make sure you're in gear before you start down because that's a bit scary
when you're just kind of careening down the hill and NOT in gear.
Most trucks are 13- and 18-speeds: fifth gear low in a tandem-tandem, fully loaded
80,000 pounds - Jake on full. That engine brake technology is good enough in this
day and age that it is going to hold the truck back and you're not going to have to use
your service brakes.
The danger is if you're not in gear and you're relying on your service brakes
down the hill,
you may experience brake fade. And again, proper breaking technique downhill. I'll put
a card up here for you.
his will take you over the video on proper downhill techniques and how to do
it in this day and age. What factors cause brake fade. As I said, in this day
and age you've got to work really hard to experience brake fade in the large
commercial vehicle. It's just not going to happen.
Make sure you get the right gear, engine brake on full. What is brake fade?
Brake fade is when you put too much pressure to the brakes, too much friction,
you're holding them on down a really steep downgrade and the brakes are
heating up.
There's a chemical reaction inside the shoes, causes them to melt, there's less friction.
The drum will actually heat up to the point that it expands away from the
shoes and you will lose braking capabilities. If you hold them on too
much, you'll even get fire and some leprechauns and marshmallows chasing you
down the roadto have no weenie roast. So brake fade - don't experience brake fade,
because you held the brakes on too long!
Use proper braking techniques. If you get in the right gear, engine brake on
full,
you're not even going to have to use the service brakes going up and down...
going down these big hills. The use of brakes on a long steep downhill is only
a supplement to the engine brake - TRUE.
You want to use the service brakes, just to bring the speed down five miles per
hour.
Now how do engine brakes work? Engine brakes work best in a low gear at high
RPMs And in a big electronic diesel engines in this day and age that higher
RPMs is 17-1800. You really don't want to run the
engine abovet 17-1800. If you do, it's just too hard on the engine. So run it up
about 1,800 in a low gear and go down the hill and the engine brake will hold that
truck back. When you're away from your vehicle for a short time you don't need to use
the parking brakes. Definitely FALSE!
Every time you stop that vehicle, every time you park it, put the parking brakes
on. How often should you drain the air tanks? Daily, daily, daily. Every day... drain
the air tanks every day.
How do you brake with a tractor-trailer unit that has ABS? You need
take note whether the trailer has ABS and the truck does have ABS.
Most of the time you're just going to brake normally. In an emergency situation,
however, you're going to hold the brake down. Hold it hard—grinding, pushback,
shutter, noise all of this stuff in an ABS equipped vehicle is normal.
Last question - you still have normal brakes if the ABS are not working and
you know that because the ABS light is on and stays on in the truck?
Even after you've exceeded five miles per hour, going up and down the road>
The answer is TRUE. You do have normal brakes once the ABS fail and the light
comes on and stays on.
They just revert to normal brakes. So know that the light is on and stays on - your
ABS is not working - that you can lock up the wheels. So then you're going to have
to do stab braking or what we call in Canada threshold braking. When you
brake hard,
bring it to the point of lockup. Release the brakes, look at the direction you
want to go, reassess the situation and reapply the brakes hard and keep doing
that until you bring the vehicle to a safe stop or you steer around the
obstacle or emergency that you need to steer around to get out of that
emergency situation. So the answer is TRUE. You have normal brakes. The ABS
stopped working.
So that concludes the chapter on air brakes in the New York State CDL manual.
This gives you further clarification and information that you need to go and
write your air brake ticket and be successful on passing. The numbers
for the in-cab checks are probably your hardest part of this information about
air brakes because it's straight memorization. It's information that you
need to memorize for the purposes of the test - both the theory test and for the
practical test that you have to do in and around the vehicle as part of your
pre-trip inspection when you go for your CDL license. One of the ways that you can
learn that information is to go and get yourself flash cards. On the front of the
flashcard write the test that you need to do. For example, the governor
test. And then on the back write: minimum and maximum. What is the maximum? How do you
know that the system is at maximum? The air dryer purges and the needle stop
climbing.
I hear...I see...I hear the air dryer purge,
I see that the needles have stopped climbing between 100 and 135 pounds and they are
no longer climbing;
therefore the system is at maximum pressure. Or the low we're warning test -
tractor protection system test -
whatever the test is, write it on the front of the flashcard. Carry them around
with you. You can just turn it over and the answer to the question will be on
the back of that flash card.
It's a great technique for those of you learning to get your CDL. And carry them
around. Anytime you're sitting around waiting or doing something that allows
you to look at your flashcards. Take a couple of minutes and get the stuff into
your brain.
It's going to help you out in terms of learning. I'm Rick with Smart Drive Test.
if you like what you see here
share, subscribe, leave a comment down in the comment section.
All that helps us out. If you need any help, any further clarification or have
questions about air brakes leave us an email at info@ smartdrivetest.com.
You can see it right here below me - the email address. As well, if you think that
you need more and you want more information, the complete information about
an airbrake system. You can see here - there's a link to a course over at my
website. you can find the complete course - it has checklists and cheat sheets. All
the valves, all of the information for pry bar test,
applied stroke method to test adjustment. tests. The in-cab checks - all of the videos - all of
this stuff will be in the course and there's ten modules.
Every time you pass a module, there is a quiz of 10 questions.
The quizzes are all multiple choice. The multiple choice questions - every answer
has feedback that will give you information about the questions that you
got wrong or the questions you got right.
If you happen to guess—not that we ever guess on multiple choice questions—sometimes
that happens.
So there's feedback for the course. You can find the link here and head over to my
website, sign up for the complete course. All of that for less
than a hundred dollars.
I'm Rick with Smart Drive Test. Thanks very much for watching. Good luck on your
CDL. Remember, pick the best answer, not necessarily the right answer.
Have a great day. Bye now.
[CLOSING CREDITS & MUSIC]