Are you working toward a career as a truck or bus driver? Inspection of air brakes is 'MUST KNOW' - watch the video!
Hi there smart drivers, Rick Smart Drive Test talking to you today about the airbrakes and the pre-trip inspection that you need to do as part of your CDL license.
For those of you in the United States, the CDL license--the commercial driver's license--for those of you working towards becoming a truck or bus driver for operating a vehicle that has air brakes you're going have to be knowledgeable air brakes and inspect the air brake components as part and parcel of your CDL license.
Now before we get started here I would like to thank Inland Kenworth here in Vernon, British Columbia, Canada for providing equipment and making this video possible.
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Now for those of you in Canada, the airbrake pre-trip inspection is going to be part of your airbrake endorsement and that's going to be a separate requirement for getting your CDL license - your commercial driver's license.
Now quickly, safety first!
Make sure you chock the wheels, pump the air pressure up over 90 pounds per square inch, in order to be able to check the air brake for adjustment, and then release the parking brakes.
And make sure that you have the required amount of air to do the outside inspection of the components.
And your mantra for the outside components are: “secure, not damaged, not leaking."
And to check the air brakes, you're going to do the pry bar (free-stroke) method. And this for the most part is the way to check air brakes.
There are some jurisdictions that will get you to do the applied stroke method.
There's another video here on the channel that will explain both the pry bar method and the applied stroke method.
After you do all the checks outside—lines, hoses, valves--check all the brakes for adjustment; you’re going to go in the cab, and there's five check in the cab. You're gonna check the governor, the low-air warning ensure that the spring brakes apply between 20 and 45psi. You're going to check the compressor that it builds with set volume of air in a prescribed amount of time. And then finally you’re to do a leak test.
And the very last test is a tug test on the parking brake and do a response test on the service brakes.
We are going to go over all of that today in more detail, so stick around we'll be right back with that information
[OPENING CREDITS & MUSIC]
Hi there smart drivers, welcome back. Rick with Smart Drive Test talking to you today about the airbrake pre-trip and what you need to do for the purposes of an airbrake endorsement. Essentially what you need to do is check the components and what you're going to say is: “secure, not damaged, not leaking.” because the components have air in them.
And the first step that you do for the purposes of your pre-trip inspection is chock the wheels, release the parking brakes and ensure that you have over 90 pounds of pressure, because you need to check pushrod travel adjustment on the brakes to ensure that they're in adjustment for the purposes of a pre-trip inspection.
So you have to release the parking brake and make sure that you have over 90 pounds of pressure in the system.
And for the pre-trip inspection for your air brakes you have to test the air tanks.
Essentially the air tanks on this truck are underneath the step, so these air tanks are up underneath the steps here. Often times, the air tanks will be up underneath the frame, and other places on the vehicle.
For a pre-trip inspection of air brakes on an older model that doesn't have an ADIS (Air Dryer Integrated System) as we said this vehicle has an ADIS system so it only has a primary and a secondary tank - it doesn't have a wet tank.
The older models will have a wet tank, and as part of your pre-trip inspection, the first step is to drain the wet tank.
And the way that you find the wet tank on an older vehicle is you go in the cab take note of what the pressure is on the two pressure gauges - because you only have pressure gauges on the primary and secondary tank. You don’t have a pressure gauge on the wet tank.
So you take note of what the pressure is, go outside and start draining tanks. The tank that you drain that doesn't drop the needles on the dash is your wet tank.
Checking the Primary & Secondary Sub-Systems
Drain that tank completely. And the reason you're draining the wet tank completely is to determine if the one-way check valves are working at the entrance to the primary and secondary tanks.
After you drain the wet tank completely, you go in and see if the needles have dropped; if they haven't dropped, your one-way check valves are working.
The one-way check valves are primarily responsible for dividing the system into two independent subsystems - the primary and secondary subsystems.
So if one system fails, the other will continue to work normally, so long as the compressor continues to work.
So you have to drain the wet tank on older systems to check the one-way check valves and ensure that your two independent subsystems are working. Now to check the air tanks on this system, the ADIS system, you just have a primary and secondary tank and these are “secure, not damaged, not leaking.”
And you're listening for audible air leaks and making sure that the drain valves are working. [RELEASING AIR FROM THE TANK]. You can see that there isn't any moisture coming out of there or any other contaminants.
Air Dryers are Really Good
Actually, filter technology is really good on these newer units and it's improved vastly in the last decade or so. And so there's very little contaminants. As well as the air dryer is incredibly effective at ridding the air of moisture and other contaminants.
So those are the air tanks that you have to check and on most newer vehicles you're going to have an ADIS system.
Air Compressors Are Parasitic
It uses the engine lubrication system to lubricate the air compressor. And so there is any oil leaking out of it. And it's in behind here on this Cummins. It's actually kind of hard to find, but just point to it, light touch, “Secure, not damaged, not leaking. The lines, hoses, and valves which are up here on the firewall “secure, not damaged, not leaking.”
You can listen for air leaks, and you don't hear anything. All the lines are secure and none of them are hanging down.
The line out to the brake chamber is not damaged, not leaking.
ABS (Anit-Lock Braking Systems)
You can see that there's a wire on this one, which means that the brakes have ABS (Anti-Lock Braking System) on them and you will also be able to tell that from the dash, because you'll turn the key to the ON position, wait momentarily and the ABS light will come on and then go out, which means that the ABS are working normally.
Determining If The Brakes Are in Adjustment
For the purposes of this pre-trip inspection test we're going to use the pry bar method and I'll put a video up here for you on how to test adjustment on brakes using the free stroke method and the applied stroke method we're going to use the pry bar method essentially just put the pry bar in here and half to three-quarters of the width of your thumbnail in terms of pry bar for the slack adjuster slack adjusters and all the components of the brakes in the inside of the hub is all secure not damaged and that's essentially all that you do for the purposes of checking this side of the engine so it's just the air brake components we're going to go around to the other side of the motor.