[AIR BRAKES :: EXPLAINED SIMPLY]
Hi there smart drivers Rick with Smart
Drive Test talking to you today about
the very fundamentals of air brake
systems. And the very basic information
that you should come out of an air brake
course with. One of the things that I've
always struggled with in terms of air
brakes is trying to explain to students
that there are two power sources in an
air brake system. An air brake system
works exactly the same as the brakes on
your car or light truck. The brakes on
your car or light truck are hydraulic
brakes. So in other words, it's hydraulic
pressure--fluid--that activates the brakes.
There's also a parking brake, and there's
also an emergency brake on your vehicle.
Now braking systems, air brake systems
and hydraulic systems are named after
their power source. The power source that
applies the service brakes. The service
brakes are the foot pedal that you use to apply
the brakes going up and down the road.
And I've always struggled with that
because in an air brake systems they
confuse students because they have
something on air brake systems that are
called spring brakes. And it leads
students, I believe, to think that there
is a different braking apparatus on the
air brake system. And if you agree with
what I'm saying here--that you believe
that spring brakes are something else
other than air brakes on an air brake
system leave a comment down in the
comment section there and let me know
that yes I was confused by those being called
air brakes and spring brakes. Because
what I'm going to try and do in this
video is to unravel that mystery for you
and explain the very fundamentals of
what you need to know in an air brake
system when you leave an air brake
course to earn your CDL license or truck
or bus license. So stick around, we'll be right
back with that information.
[INTRODUCTION & MUSIC]
Hi there Smart Drivers. Welcome back, Rick
with Smart Drive Test, talking to you
about: The very basic information that
you need to know when you come out of an
air brake course. Alright, when we drive
our passenger vehicle, there are three
brake types on your vehicle. You have a
service brake, which is the foot pedal,
when you go up and down the road, you
apply the foot pedal, and the vehicle
comes to a nice gentle stop... Most of the
time, 99.9% of
the time. All systems are divided into
two independent subsystems, so it's
unlikely that braking systems, regardless
whether it's a hydraulic braking system
or an air brake system, are going to fail.
So, service brakes is the foot pedal. The
next brake that you have on your vehicle
is the parking brake. And, I know here, in
North America, 85% of us
drive automatic transmissions, and
85% of people who drive
automatic transmissions, 90%
of those people never use the parking
brake. But, there is a parking brake on
your vehicle, and I would strongly
suggest that you apply it before you put
the vehicle into park, because it's hard
on your transmission when you don't
apply the parking brake. Now, if the
service brakes fail, the foot pedal fails,
and you don't have brakes going up and
down the road, you can pull the parking
brake on, using the power from your body,
and the lever is attached to a cable to
the brakes on the back, and bring the
vehicle to a stop. Now, you're using the
parking brake as an emergency brake. So,
the three systems on your passenger
vehicle are: Service brakes, the foot
pedal. The parking brakes, which the
energy comes out of you, as you pull up
on the ratchet mechanism, or push the
ratchet pedal down on the floor. And if
the service brakes fail, you can use the
parking brake to bring the vehicle to a
stop, and thus the "parking brakes" become
the "emergency brake". Now, they're called
hydraulic brakes, because that's the
power source for the service brakes. Air
brakes work exactly the same. And what
confuses students on air brake systems,
is that we have something on air brake
systems that has been referred to, for
almost 40 years now, called spring brakes.
Spring brakes only serves to confuse
students, and if this has confused you,
then leave a comment, down in the comment
section, and tell me that I'm on the
right track. Because as I said, I'm
writing a book, a manual, called
"Air Brakes Simplified", which is trying to
simplify the system, and explain air
brakes to you better. All that spring
breaks are: Is another power source on an
air brake system. On an air brake system
we have service brakes, which is the foot
pedal, and it applies the brakes on the
vehicle using air pressure. Thus,
they're called air brakes, like hydraulic
brakes are called hydraulic brakes on
your car or light truck, because they're
powered by hydraulic pressure. We also
have parking brakes on large commercial
vehicles, and these do, in fact, have to be
applied every time you leave the
driver's seat, there's no doubt about
that, apply the parking brakes! There's
two buttons on the dash, if
you're in a tractor-trailer unit, there
will be two buttons, there's a red one,
and a yellow one. The yellow one is the
parking brake control valve. The red
eight-sided button is the trailer air
supply valve. And those are on/off
switches, they apply the parking brakes,
"on" "off". Now, the difference between a big
truck, a commercial vehicle that is
equipped with air brakes, or an RV unit
for that fact: Is that the parking brakes
are powered by large powerful springs.
These large powerful springs are another
power source that apply the parking
brakes, and their best used for parking.
Now, what happens is, you're going up and
down the road, and lose the service
brakes, on an air brake equipped vehicle:
The air drains down, the air drains down,
because what happens is, when you push
the buttons in on the dash to release
the parking brakes, air pressure
compresses those large powerful springs.
If you lose air pressure in the system,
those Springs are no longer able to be
caged or compressed, and because you
don't have enough air pressure to
compress them, they come on. The challenge
with all of these manuals, is that they've
referred to these as spring brakes. And
students come into the class, and you try
and explain this to them, and they're all
thinking "Are there... is there another
brake on the truck, the commercial
vehicle, or the vehicle fitted with air
brakes?" No, there isn't. It's simply one
air brake chamber,
that converts air pressure into
mechanical force, and that applies the
service brakes, the foot pedal, and you've
got another one on the back of it, with
this large powerful spring in it that's
held off in the release piston with air
pressure, when you evacuate the air
pressure from that spring brake chamber,
that large powerful spring comes on, and
applies the same brakes. It's the same as
what's on your car or light truck. You're
not using different brakes, you're just
using a different power source, which is
coming out of you, via a cable back to
the brakes and pulling the brakes on. On
a big truck the emergency and parking
brakes are powered by these large
powerful springs, and held off by air
pressure. Both systems, a hydraulic system,
and an air brake system, have service
brakes, the foot pedal when you go up and
down the road. They have parking brakes,
that apply the brakes indefinitely. On
your car or light truck, it's just a cable
with a ratchet mechanism, like a boat,
*click* *click* *click* *click* *click* You click
it up, it locks the brakes in to place
indefinitely. On a large commercial
vehicle, when you evacuate the air from
the system, the large powerful springs
come on, and apply the brakes, the same
brakes that the air brakes work, going up
and down the road. If you lose air
pressure in a large commercial vehicle, a
large vehicle I'll say, because RVs and
buses are also fitted with air brakes, in
this day and age, because they're
reliable. If you lose the air pressure,
those large powerful Springs will come
on, and apply the same brakes as all the
other brakes. So all the brakes -- the
service brakes, the parking brakes, and
the emergency brakes -- all use the same
foundation brake system, whether it's a
drum brake or a disc brake. So that is
one of the things that I think leads to
confusion when students take air brake
courses, is that instructors say to them
"Oh, there's air brakes and there's spring
brakes!". So students are thinking "Well
there's two different kinds of brakes on
the vehicle", and no there's not. There's
one brake, there's two power sources. As I
said, again, just to reiterate, service
brakes, the brake pedal. Parking brakes,
and emergency brakes. Parking brakes and
emergency brakes are one in the same
thing, they're just used for different
purposes, and when they're used for
different purposes, they're called
different things. When you park the
vehicle, they are called parking brakes. When
you need to bring the vehicle
to a stop, because the brakes failed,
they're called emergency brakes. And
hopefully that clears up some of the
confusion that you might have, taking a
CDL air brake course. And if you've had
that confusion, and now you understand
"service brakes" "parking brakes" "emergency
brakes" aren't the same on hydraulic as on
air brakes, leave a comment, down in the
comment section there, that'll really
help me out in terms of finishing up the
air brake manual. Question for my Smart
Drivers: Have you been confused in an air
brake course, by how the "service brakes"
"parking brakes" and "emergency brakes" work
on an air brake system? Leave a comment, down
in the comment section there, all that
helps out the new drivers working
towards getting their CDL license. I'm
Rick with Smart Drive Test, thanks very
much for watching. If you like what you
see here, share, subscribe, leave a
comment, down in the comment section. As
well, hit that thumbs up button. Check out
all the videos here on the channel if
you're working towards the license, or
starting your career as a truck or bus
driver, lots of great information here. As
well, head over to our website, awesome information
over there, and tremendous online courses
that you can purchase. We're bringing out
"Air Brakes Simplified", the manual for CDL
drivers in May 2017, so look for that,
it's going to be an e-book, it'll be
completely interactive, and it'll have a
hundred multiple-choice questions that
you will be asked on a CDL license.
Thanks again for watching, good luck on
your road test, and remember: Pick the
best answer, not necessarily the right
answer. Have a great day, by now.
[OUTRO & MUSIC AND AIR BRAKE AIR PRESSURE MOVING THE PUSH ROD AND ACTIVATING THE SERVICE BRAKES]