[TITLE: HOW TO ADJUST A MANUAL SLACK ADJUSTER TO PASS CDL AIR BRAKES]
Hi there Smart Drivers, Rick
with Smart Drive Test talking to you today
about how to adjust a manual slack adjusters
for the purposes of your CDL license test.
You are not going to do this on any modern air brake system,
they're all gonna be equipped
with automatic slack adjusters.
You can see here in the salvage yard
I had to walk around here for about a half an hour
before I actually found this old
probably 1970s maybe early 80's Ford Louisville
that was equipped with manual slack adjusters.
You can tell how old this truck is
'cause it actually says on the hood diesel engine
which signifies the transition
between gasoline engines and diesel engines.
For big trucks, that happened in the early-70s
and that was one of the selling features
for this old Ford Louisville and
at one time the Ford Louisville actually was the
industry standard so it's a pretty old truck.
So you're not gonna ever have to adjust
a manual slack adjuster it's really unlikely
because they've gone the way of the dodo bird,
but for the purposes of a road test
a CDL license test, you're gonna have to do it.
So we're going to do that today,
we're going tyo show you how to do it
and at some licensing centers here in British Columbia,
for example, if you cannot explain how to set up
a manual slack adjuster it's an automatic fail
on the air brake portion of your CDL test
so you have to be able to do it.
If you go down with a school
they're going to have a vehicle that has
a manual slack adjuster on it
and you have to demonstrate it or you have to give a verbal.
The driving examiner will just show you
a picture of a manual slack adjuster
and you'll have to give a verbal.
So the steps are: chock the wheels,
pump the air pressure to over 100 pounds per square inch,
release the parking brakes, get out,
determine that it is in fact out-of-adjustment
by using the pry bar method for the most part.
You might have to use the applied stroke method
and I'll put a card up in the corner for you here
on determining air brake adjustment.
Once you determine that it's out-of-adjustment
you take your 9/16 wrench, push it over the adjusting nut,
you'll have to release the locking sleeve
and we'll show you how to that,
and then turn the adjusting nut so the S-cam
rotates in the same direction as the brake application.
We'll show you, that's key.
Turn the adjusting nut so the S-cam rotates
in the same direction as a brake application.
Then you turn it all the way until the nut goes tight
and you shouldn't have to turn it
more than one or two revolutions at the most.
If you're turning it more than one or two revolutions. If so,
you're probably going the wrong way.
Turn it until the adjusting nut goes tight, check that it is in fact tight
because what you've done is manually tightened,
or manually applied the brake.
Manually apply the brake, take your wrench,
and back it off a third to half a turn,
and then make sure that the locking sleeve
is re-engaged over the adjusting nut,
the 9/16 nut, put your pry bar in
and make sure that it's within adjustment.
After you do that you have to adjust
both manual slack adjusters on both sides of the axle
so know that as well that if you do one you've got to do
the one on the other side of the axle as well.
So what we're gonna do today, we're gonna demonstrate
how to do that, so stick around,
we'll be right back with that information.
[INTRO AND UPBEAT MUSIC]
Hi there Smart Drivers, welcome back,
Rick with Smart Drive Test talking to you today
about how to adjust a manual slack adjuster
for the purposes of a CDL license test.
As I said in the introduction,
it's not likely, in this day and age
on an air brake system you're gonna find
manual slacks - it's really unlikely.
Now, to get started you're gonna need a 9/16 inch
box and wrench, you're gonna need a set of wheel chocks
to secure the vehicle against movement,
you're gonna need a pry bar
if you're doing the pry bar method,
if you're doing the applied stroke method
you're gonna need a measuring device
and something to mark the push rod
at a fixed position so you can measure
how far it comes out of the brake chamber.
As well you're gonna need a pair of gloves,
always wear pair of gloves when you're working
on the vehicle. That way you can keep the dirt
outside of the vehicle when you get
into the vehicle you can take your gloves off.
But again, as I said, this is only
an exercise for doing a license test
and those are the tools that you're going to need.
Now minimum you're gonna need a hammer,
a 9/16 inch wrench, and a pair of gloves
and that'll get you going on being able
to adjust a manual slack adjuster.
Now for the most part, on most license tests
you're just going to have to do a verbal
and the two key phrases that you say are:
I turn the adjusting nut in the same direction
as the S-cam Rotates for a brake application.
And we'll show you how to determine that.
As well, we're going to show you that
how to re-engage the locking sleeve over the nut.
That's the last piece you have to say.
Those are the two key phrases.
And again, I'll leave a description down
in the description box here for a complete
written list, checklist, of things that you need
to do to adjust a manual slack adjuster.
Find that down in the description box.
First thing we have to do is we have to
push in the locking sleeve on the 9/16 box end
we need the adjusting nut so this is
the adjusting nut here, you push that in,
you can see this goes in fairly easy.
Now you might need a hammer
and bang on the box end to get that in.
So the first thing we need to do for adjusting
a manual slack adjuster is we put the pry bar
on here and we can see that it's a little bit loose.
Here, actually, I'll just adjust it.
Adjust it off here a little bit and then
you can see that it's actually out of adjustment.
So we put our pry bar in here and we can
say okay that's out of adjustment.
So the first thing we need to do
is we need to put our wrench on here,
push the locking sleeve in,
and then we turn it so that the S-cam rotates
in the same direction as the brake application.
So the way that we determine that
is the push rod extends this way out of the brake chamber
and we think of it like a wrench on a nut
so this is coming out so we turn it this way.
So the S-cam has to rotate in this direction
when we're turning the adjusting nut.
So this is the only piece, when we turn
this adjusting nut here, this S-cam--
the end of the S-cam right here--
is the only thing that should rotate.
So we put our 9/16 wrench on the adjusting nut,
when we turn that we can see that the S-cam
is rotating in this direction,
the same as the wrench on the nut, this way here.
So we put that on there and we turn
the adjusting nut until it goes snug,
so it's snug so we take it off,
we get our pry bar, we put it in
at the clevis pin here
and we try and pry the push rod out
of the brake chamber. And it doesn't come out.
So that means that we've manually adjusted the brake.
So now we put the wrench back on
at 90° degrees this way. And we want to go back
a quarter to a half a turn. So we come back
just a little past a quarter turn,
we make sure that the locking sleeve comes out,
and it has in fact. We put our pry bar back on,
and we make sure half to three quarters.
So we can see that it is now in fact adjusted.
So this locking sleeve does not fully
encase the adjusting nut on here.
Most of them do but this one doesn't for whatever reason,
so we can just try and move that a little bit,
and sometimes you can tap the end of the bolt too
and that will bring the adjust,
the locking sleeve out over the adjusting nut
but this has to be fully engaged over the adjusting nut
and that's the last thing that you say to the examiner is,
I would ensure that the locking sleeve is engaged
over the adjusting nut. Because if it's not engaged
it's just going to go out of adjustment again.
So after you finish adjusting this one
you go over the other side.
So again, quickly, pry bar, make sure
it's out of adjustment, this way here,
we figure out which way the S-cam rotates
for brake application think of it like a wrench on a nut.
So the push rod extends this way,
therefor it's going to rotate in this direction.
In a counterclockwise direction,
so we put our 9/16" wrench on the adjusting nut
and we turn that until it goes tight
and we can see that this S-cam is rotating
in a forward motion towards the front
of the vehicle which is the correct way.
The adjusting nut has gone tight,
we check to make sure that the push rod
will not extend out of the brake chamber,
because we've manually applied the brake,
which it has and now we take the adjusting nut
and we crank it back a quarter to a half a turn.
So we just go past a quarter of a turn there,
we make sure that the locking sleeve is re-engaged,
and we make sure that the push rod is within adjustment,
and it is within adjustment which is the width
of our thumb nail and that's how you
adjust a manual slack adjuster.
Quick review of manual slack adjuster,
as I said, for the purposes of a CDL license test
you're gonna have to do this
but for actually adjusting of a manual slack
on a modern air brake system it is very very unlikely
that you're gonna have to do this.
As I said, Coldstream Truck Parts here in Vernon,
I walked around this yard here for a good half an hour
before I found this old Ford Louisville
that actually had manual slacks on the front of it
that I could demonstrate to you
how to adjust up a manual slack.
And know as well, here in British Columbia,
and some other jurisdictions, if you cannot
explain or demonstrate how to do-
how to adjust a manual slack adjuster
that's an automatic fail on your air brake.
So just know that as well.
In some cases you're going to have to give a verbal
especially if you don't have a vehicle
that doesn't have manual slacks on it.
If you're going with a training truck
there's a good chance it's going to have
manual slacks on it that you can demonstrate that,
but for most part you're going to do a verbal.
So the tools you need when you're doing
the pry bar method, you're gonna need
a pry bar, you're going to need a pair of gloves,
you're going to need a hammer,
and you're going to need a 9/16" inch box and wrench.
All manual slack adjusters have an adjusting nut
that is a 9/16" adjusting nut,
so you're gonna need a 9/16 box and wrench
to adjust up the manual slack adjuster.
So the first thing you do, chock the wheels
and ensure that you have system pressure over 100 pounds
and release the parking brakes on the unit.
Then you come out, you determine that
it is in fact out of adjustment,
you determine which way the S-cam has to rotate
to make a brake application,
think of it like a wrench on a nut.
So you just, whichever way the push rod extends
out of the brake chamber just follow that around
and that's the direction that the,
you're gonna turn the adjusting nut so the S-cam rotates
in the direction of the brake application
as you saw here when we did this one here.
So you release the locking sleeve over the nut,
turn the adjusting nut so the S-cam rotates
in the same direction as the brake application,
turn it until it goes tight, if you turn it more
than one or two full revolutions
you're probably going the wrong way.
So once it goes snug then you take your pry bar,
pry on the push rod, it should not extend
out of the brake chamber because you've manually
applied the brake, and then at that point
you take the adjusting nut and you back it off
a quarter to a half a turn.
Usually just about a third is really good,
that's generally the best.
So you back it off, make sure the locking sleeve
re-engages and then take your pry bar
and make sure that it's within adjustment
and if you're doing the pry bar method
it shouldn't come out of the brake chamber
more than the width of our thumb nail.
And then finally, if you do one on one side
of the axle you'll have to go over and do
the other one on the other side of the axle.
So that's how you adjust a manual slack adjuster
for the purposes of a CDL license test.
Question for my Smart Drivers [CHUCKLES],
after you got your CDL license
have you ever adjusted up a manual slack adjuster?
Leave a comment down in the comment section there,
all of that helps out the new drivers
working towards getting their CDL license.
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Check out all the videos here on the channel
if you're working towards a license
or starting a career as a truck or bus driver.
Lots of great information here,
as well, head over to my website,
awesome information over at my website
and tremendous online courses that you can purchase.
As well, the air brake course is available
over there that you can purchase and take.
And in May 2017 we're bringing out
Air Brakes Explained Simply,
it updates the forty year old air brake manuals
in North America that are currently in circulation
as well it has 100 multiple choice questions
that you will find on a CDL license exam.
So look for that in May 2017.
I'm Rick with Smart Drive Test,
thanks very much for watching, good luck on your road test,
and remember, pick the best answer,
not necessarily the right answer.
Have a great day, bye now.
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