Video Text Here!!
Name of Video Here!
Alright, sorry about that, I think I might have the audio working for you now. And starting with the CDL air brakes and getting your air brake ticket for the purposes of getting a commercial driver's license. Alright, sorry about that - I think I might have the audio working for you now and perfect awesome. So air brakes without further ado - getting started here. What I was saying previously about air brakes is that most of these jurisdictions in North America because you're required to get an airbrake ticket to drive a commercial vehicle and as well a RV unit in the United States and in Canada if it has a four-sided yellow button on the dash - it's going to be an airbrake unit and you need to get an airbrake ticket. The problem with these airbrake courses is that they're forty years old. They devised these courses in the 1970s and unfortunately they have not been revisited and amended and you're just not going to find manual slack adjusters on an airbrake system; you're not going to find a single circuit system - it's all dual airbrake systems; it's all automatic slack adjusters and there aren't any wig wigs - all the low-air warnings on air brake systems in this day and age are all going to be a light and a buzzer. So what I'm going to do today is talk to you about air brakes. Mostly what I'm going to talk to you about is the pre-trip inspection that you have to do for the purposes of getting your license. And for those of you going to truck driving school or getting your bus license - school buses as well. You're going to go to a school you're going to do a pre-trip inspection. And you're going to have to do a practical component of that which is - you're going to have to inspect the air brakes and make sure the air brakes are in adjustment. And make sure that all the components are working. The in-cab portion of the pre-trip inspection is probably the most difficult because it's pure memorization. But there's essentially--in any jurisdiction that you're going to be taking a pre-trip inspection for the purposes of getting your air brakes-- there are five basic tests that you have to do in the cab rather, of the vehicle whether it's a bus, it's a truck, or RV unit. And those five tests are: you have to test the governor - the minimum and maximum settings of the governor. You have to test the low air warning and make sure that the spring brakes come on between 20 and 45 pounds per square inch. You have to test the compressor that it will build a prescribed amount of air in a set time. Most of that time it's going to be 50 to 90 pounds per square inch in three minutes at a high idle, which is about a thousand rpm on a diesel engine. And then you're going to do a leak test. And the last two tests of your pre-trip inspection are going to be a service brake response test on the service brakes and you're going to test the parking brakes. You're going to do a tug test on the parking brakes. So what I'm going to do here is get on with the presentation for the PowerPoints. And I'll just go through that quickly. So a little bit of bonus material down here - braking you use engine brake. Your engine brake, in this day and age, engine brake technology is really, really good and it's not likely that you're gonna have to use your service brakes. If you're in the right gear going downhill you're not going to have to use the service brakes. You just have to get in the right gear before you get out over the top of the hill. Now if you're driving a big truck‚Äî13- and 18-speed you're going to be in five low if you're driving tandem-tandem. So it's an 18-wheeler and you're running 80,000 pounds, and if you're in five lo you're going to be able to go down the hill. If you do need to make service brake applications if you're driving a pickup truck or RV unit or something like that, make hard, short intermittent brake applications. That way if you let off the service brakes, you're going to be able to allow air to pass over the drums or the disc brakes and allow them to cool. Grade signs - pay attention to grade signs on long downhill grades, especially if you're in the Rocky Mountains, for those of us on the west coast of North America. If it's less than one kilometer or one mile and the grade is less than ten percent, you just use your service brace. If it's more than a mile or more than a kilometer and or it's greater than 10-percent, then you need to gear down and start preparing to go down that long downhill. Now most great signs are in percentage so this one here--you can't really see it in the image that well--is seven percent and seven percent is for every one kilometer your go forward goes the hill drops 70 meters or if you're in feet - for every hundred feet you go forward the hill drops seven feet. So that's how you read a grade sign. So I'm Rick August, PhD, I'm the founder and the chief driving instructor of Smart Drive Test. And if you're here on my YouTube channel you can see there's lots of good information here about not only about air brakes and getting a commercial license, but also for those drivers getting a new license. So that's Smart Drive Test. And as well, for those of you getting a commercial license most of the information on the YouTube channel is the class 5 stuff - the car and light truck stuff is fair game for getting a higher class commercial license, so make sure you pay attention to the other information as well. And for the purposes of getting a license you have to know where to stop in traffic and all of the other traffic rules apply: how to make a left hand turn; how to make a right hand turn - all those rules are going to apply on a commercial driver's license. So pay attention to the class 5 stuff as well. So large commercial vehicles and stopping distance - take note on your driver's test that if they ask you what stopping distances or total stopping distance is there's a difference between those two things. Stopping distances - the time that passes from when you put your foot on the brake pedal to the vehicle comes to a stop. Total stopping distance, as you can see here in the slide, is driver's perception time, reaction time, brake lag time, braking distance, which equals total stopping distance. So just on your driver's test take note of that and make sure you look at those keywords. And of course, all of this is in a in a large vehicle whether, it's an RV unit, or bus or truck. It is going to depend on the ability of the brake linings to produce friction and the brake drums to dissipate the heat and the tires to have traction on the roadway. Speed and weight factors, and this is in Canada - I haven't seen this question in the United States, but I have seen in Canada. If you increase the speed of the vehicle - if you double the speed of the vehicle, it requires four times the stopping power to stop the vehicle, as you can see here in the image. So speed - twice the speed requires four times the stopping power to bring the vehicle to a stop in the same distance. The way that you remember this-- the pneumonic on this is: "2 weight 4 speed." So it's 2 times the braking power; if you double the weight it's four times the braking power. If you double the speed and if you put the two of them together you're going to need eight times the stopping power. So if you double the speed and double the weight, you're going to need eight times the stopping power to bring the vehicle to a stop. And a large commercial vehicle is involved in police-reported casualties with air brakes is undo care and inattention. And of course, in this day is going to be distracted driving, unsafe speeds. And the top two factors assigned to commercial drivers being involved in police-reported casualties and it's kind of a catch-all - it doesn't really give you a whole lot of detail as to exactly why commercial vehicles are involved in police-reported casualties. So greater stopping distance, obviously when you're driving a larger commercial vehicle that has more weight. It's going to take longer for you to stop that vehicle higher speeds require more stopping power. Trucks require more space to stop therefore you have to compensate for that. One of the ways that you do that is scan farther head, farther down the road and you brake earlier. And of course with a large commercial vehicle, slopes and grades are going to become a factor as well in a large commercial vehicle. As well, in a car and a light truck when you're braking you're going to come to a defensive stop. So as you come to a complete stop just before you come to a complete stop - you let up on the brake pedal to allow the body to settle back over the chassis because all vehicles are comprised of two parts, which is the chassis and the body. And if you hold the brakes down until the vehicle comes to a complete stop, the body slingshots back over the chassis and gives you a bit of whiplash. And again, there's a video here on the channel, as well, about how to know if your vehicle has come to a complete stop. And so, as I said, this applies to all vehicles, not just commercial vehicles. Downgrades - most overheated brakes on a downgrade result from poor braking techniques. And an 18-percent grade--you can see there in the sign--is an incredibly steep grade. And you want one or two years lower to go down the hill then you used to climb the hill. Now as I said, in British Columbia, on the west coast of the United States in the Rocky Mountains, in Virginia and other places that have mountains, a lot of times you're not going to go up a hill to go downhill. So if you're driving a 13 or 18-speed, you need to know that you want the vehicle in five low if you're driving tandem-tandem at a legal weight. If you're running heavier than that or you have an automatic transmission you want to get down into a really low gear. And again, when it comes to descending downgrades you can go down the hill a thousand times too slow, but it's the one time that you go down too fast maybe you're last. So until you're used to the vehicle, until you're use to the hill, just go down to slow. Now CDL airbrake courses - one of the things that they don't talk about is they don't talk a lot about signs, specifically directed to large commercial vehicles. And here in British Columbia, where I live, these signs with the dashed border are specifically for commercial vehicles. And these are regulatory signs. So if you have a brake check where trucks have to pull in or large commercial vehicles - you have to pull in and you have to do a brake check. So some of these are regulatory signs and as we know these are rectangle signs with the white background, and have black writing on them or symbols, And these are regulatory signs which the root of regulatory is regulation which means that you have to stop. The other ones are advisory signs - 30 kilometers an hour. Now most of the time if you have a hill that has been a cautionary sine of 30 kilometers an hour you want to make sure that you're doing 30 kilometers an hour when you're going down the hill. A good practice, if you're doing less than 60 kilometers an hour on an 80 kilometer an hour or above highway, you want to activate your for way flashers to indicate to other traffic that you are going slow. So in the United States that would be 40 miles an hour - if you're doing less than 40 miles an hour, you want to activate your four-way flashers to indicate to the traffic that you are in fact going slow. And this is very true in this day and age of improved technology of engine brakes and whatnot. If you're in the right gear before you start down over the top of the hill and have your engine brake on full, you should be able to get down the hill without relying on your service brakes. So just talking a little bit about pre-trip inspection - inspecting airbrake components So for purposes of securing your vehicle you need to secure the vehicle first by putting in wheel chocks, which are basically blocks to secure the vehicle against an inverted movement. Because you do need to release the parking brakes to check air brake adjustment. And you're going to do functional checks of the airbrake system. And then you're actually physically checking air brake components on the vehicle and say, "secure, not damaged, not leaking" is going to be your mantra because about 75% of the components on the vehicle either have fluid or air in them. So you're going to say that: "secure, not damaged, not leaking." Safety first as I said: secure the vehicle to make sure that your wheel chocks are in. And then you're going to build the system air pressure over a hundred pounds and you're going to locate the wet tank. If you have an older vehicle that doesn't have an ADIS (Air Dryer Integrated system) ADSIS stands for air dryer integrated system - these newer air brake systems do not have a wet tank, but if you do have a an older air brake system, probably earlier than 2010, it is going to have an older system on it. And it's going to have a wet tank and so it will have three tanks. It will have a wet tank, a primary tank, and a secondary tank. You have to locate the wet tank on the vehicle. You go in the cab and take note of what the air pressure gauges read. And then you go out and start draining tanks. And the one tank that doesn't drop the needles on the on the dash - that's going to be your wet tank. You want to drain the wet tank completely. And the reason for draining the wet tank completely on the system is to check the one-way check valves at the entrance to the primary and secondary tanks because these two valves - these two one-way check valves are primarily responsible for the division of the system into a primary and secondary subsystem. Draining air tanks: the question on the test--the CDL test--is how often do you drain wet tanks, rather how often do you drain the air tanks on your vehicle? You drain the tanks every day. That's the answer to the question on the test, regardless of where you are in North America or the world. Drain the air tanks every day. You drain air tanks and then ensure that the pressure is within normal operating range and shut off the vehicle. We already went over all that - drain all the tanks. So that was basically what it was. Inspecting air brake components: "secure, not damaged, not leaking" - you're looking for broken components, frays, wears, those types of things. You want to be testing all of the foundation brake components and for most of the jurisdictions in North America you're going to be doing the pry bar method. And the pry bar method is simply to put a pry bar in at the clevis pin and pull out and do a pry bar method or it's sometimes called the free stroke. And essentially the pushrod shouldn't come out of the brake chamber--the pushrod should not come into the brake chamber more than the width of your thumbnail. In most states in the United States it's an inch, but the width of your thumbnail is approximately half inch to three-quarters of an inch, which is going to tell you that it's within adjustment. Brake chambers on an airbrake-equipped vehicle are the primary component. They are the components that convert air pressure into strong mechanical force. You want to make sure that the size of the brake chambers [COUGHING] excuse me, match across the axles - that pushrods attached to the same home on both sides of the axle. As well, that these are secure and no visible damage. Brake drums and rotors, secure, no damage, and are round without irregular wear. Airlines and tubing - there isn't wearing or structural damage. Secured, not hanging down, and air tanks - secure, no damage, and no audible leaks. Because you have the wheels chocked and you have the parking brakes released on the system, there is air in the system. So as you're going around the unit, you're going to be able to listen for air leaks. All of the compressors, most of the manuals will tell you that compressors are either belt-driven or gear driven. In this day-and-age they're all gear-driven. These are bolted right to the side of the engine. You're not going to find any that are belt-driven - it just doesn't happen in this day and age. Secure, not damaged - there's no oil leaks. The compressor is truly parasitic - it takes power from the motor. It uses the motors filtration system, and draws air in. It uses the engine's lubrication system - so make sure there's no leaks. And if there are belts, in the odd case, that you're doing a pre-trip inspection on a pre-1980 vehicle - it might have belts, but just make sure they're in good nic - they're not frayed or damaged and they have proper tension. The governor - testing governor settings. So think of the governor on an air compressor like a thermostat on a furnace in your house. It runs within a temperature - a minimum and a maximum pressure rather. So the engine's running, ensure the parking brake is released, and the governor should restart the compressor above 80 pounds per square inch. We don't use kilopascals in North America. In North America we use pounds per square inch. So one of your in-cab checks is to test the governor settings. You're going to test the minimum setting first, because you're going to pump down and what I'll do after the presentation is when I put the description down, I'll put a link to my website and there's an info graphic that will show you how to do the in-cab checks. And what you have to do--so after you do the minimum setting, you pumped down to above 80 pounds, throttle up, and make sure that the needles are rising, therefore you know that the governor has put the compressor back into the load phase or the cut in phase as it's sometimes called. Then you're going to continue to pump down to 60 pounds per square inch. In some states, some jurisdictions, some provinces want 55psi or above - it's mostly 60 pounds per square inch that the low-air warning will activate. On older trucks it will be a wig wag, but as I said, these haven't been around for 30 years. I think what happened was is that the wig wag dropped down from behind the sun visor and scared the living daylights out of a couple drivers and they drove off the road and crashed into a tree and died in a fiery inferno. So the engineers when you know, maybe we'll just go with a light now buzzer. That sounds like a much better idea. So we don't have wig wags anymore. So the low-air warning should come on above 60 pounds per square inch. And on many vehicles, on buses they're going to come on well above 60 psi. Sometimes the low-air warning comes on as high as 80 psi. So low-air warning - just fan the brakes down until the low-air warning comes on. Testing air pressure build-up so in many states you are going to pump down to make sure that the spring brakes activate after you check the low-air warning. And simply, you're just going to pump down between 20 45 pounds per square inch and the buttons on the dash will pop out activating the spring brakes, which are the parking brakes on the unit. After which you test pressure build-up. So after you do that, then you're gonna throttle up, get your timer out - when the first needle hits 50 psi you start timing. When the second needle gets to 90psi, then you'll stop timing. On the way up the low-air warning is going to go out, and you'll say to the examiner when you're doing your CDL test: "the low-air warning has gone out and the system built 50 to 90 psi well within three minutes. Essentially what you're saying to the examiner is: you tell them what the parameters of the tests are and then tell them that the air brake component passed the test. That's all you need to do. Then you're going to build to maximum pressure. So we'll just go back to this one here - building the compressor, so when you get to 90 psi, you're going to release the parking brakes again. And then you're going to build to maximum pressure. And the way that you know that the system is at maximum pressure is, the air dryer will purge and you'll check the air pressure needles and say: "the needles have stopped climbing, therefore the governor has put the compressor into the unload phase with a cut-out phase and therefore I know the system is a maximum pressure and the governor is working. Then you're going to shut the truck off and you're going to do a leak test. On a single unit you're allowed to lose no more than three pounds, on a truck and trailer you're allowed to lose four pounds; in a truck with two or more trailers, you're allowed to lose no more than six psi. So essentially just build it up to maximum pressure, shut the engine off, make a full service brake application and hold for one minute. After the initial drop, you're not allowed to lose three pounds, on a single unit, four pounds on a truck and trailer, and six pounds on a truck with more than one trailer. And then the final tests for your air brake pre-trip inspection is testing the vehicle's spring brakes. So you simply apply the parking brakes, put the vehicle in a low gear, and make sure you have over 90 pounds and then try to move the vehicle forward. If it doesn't move forward, then you know the spring brakes are working. And then the last piece is to release the parking brakes, roll the vehicle ahead a few feet and apply the service brakes and make sure that the service brakes bring the vehicle to a stop and that they also released, because it's a response test to make sure that the service brake apply and release. So then you'll apply the brakes on your unit and fill out your pre-trip inspection. Because all commercial drivers have to fill out a pre-trip inspection form as part and parcel of their job. And you fill out a pre-trip inspection form every day. So that's a quick presentation. If you have any questions at all ,just leave them in the notes here and I'll be more happy to answer questions for you about getting your air brakes for the purpose of getting a CDL license. And we'll just put in here - so air brakes basically for those of you working towards getting a CDL license and doing air brakes - you're going to find air brakes on tractor-trailer units, you're going to find them on five ton trucks, you can find them on some RV units, and definitely on school buses. So if you're driving any of those units, you're going to end up having air brakes on the vehicle and you're going to have to be knowledgeable about air brakes and know about air brakes and how air brakes work. Now the other thing you need to know about air brakes, which is just a little bit different than hydraulic systems, is that if you pump the brakes on an airbrake system, you're going to lower the air pressure in the unit because after you make a brake application on an airbrake equipped vehicle, what happens is the air is exhausted from the system by the quick-release valve. And the quick-release valve reduces brake lag because there's a slight delay from the time you put your foot on the brake pedal to the time that the brakes activate and vice versa. So essentially what happens is it reduces brake lag in the system. Air is exhausted from the airbrake system into the atmosphere. So if you pump the brake pedal on an airbrake system, you're going to lower system pressure. And if you do it enough ‚Äì yeah, eventually you're not going to have any brakes. So you want to make sure that you don't pump the brakes - you simply hold down and make a firm brake application on an airbrake equipped vehicle. And I've had students do that going downhill. Not very often, but once in a while they'll pump the brake and they'll drop the air brake pressure. And if you're going down a long, steep downgrade then what's gonna happen is you're gonna end up with no brakes. So you can't do that on an airbrake system. It‚Äôs the difference between an airbrake system and hydraulic system. Now the other piece that I'll say about airbrake system is, unfortunately we make airbrake system is very complicated and they're not that complicated because they're really not that much different than the brakes that you find in your car or light truck. Essentially in your car or like truck you have a service brake, which essentially the brake pedal. You push down on the brake pedal and the vehicle comes to a nice gentle stop; and it's the same thing in an airbrake vehicle. You release the parking brake, and push down on the brake pedal when you're coming up to a traffic light or whatnot and the vehicle comes to a gentle stop. It's exactly the same as what happens in your vehicle. The other piece about air brake systems is they have parking brakes and you need to apply the parking brakes every time you get out of the vehicle. On your car light truck, you also have a parking brake, but instead of using spring pressure, which is what they use on air brake systems, you use your arm or use your foot - it's like a ratchet, so you apply the parking brakes. And you know for some people who get in big trucks, it's a bit odd because you have to put the parking brakes on every time you stop the vehicle to get out of it. And you should get in the habit of doing that in your personal vehicle as well - just saying. And the final piece about your personal vehicle is if you lose your brakes on your personal vehicle you can use that parking brake as an emergency brake. You can pull it up and it will activate the brakes. It's the same thing on a big truck or an RV unit that has air brakes on it - if you lose air pressure in that system those spring brakes will no longer be held off because there's no air pressure and those spring brakes will activate automatically, and the vehicle will come to a stop. So you're not going to lose you're the brakes. The brakes won't fail in an airbrake system - there are too many fail-safes and there‚Äôs a video here on my channel called air brakes won't fail which goes through all of the fail-safes in an airbrake system that will show you that in fact it will not fail. And in this day and age, air brake systems are almost bulletproof. And one of the main fail-safes on an airbrake system is the dual air brake system. The system is divided into two independent subsystem - so if one system fails--one side fails--the other system will continue to work normally. And it's the same on your car or light truck. If you go in under the hood of your vehicle--open the hood up--and right in front of the steering wheel on what's called the firewall, you'll find the master cylinder. If you take the lid off the master cylinder and look inside, there's two chambers in there - one is for the front brakes and one is for the rear brakes. So if one system fails, the other will continue to work normally - you will not lose your braking system because it's two independent subsystems. So an airbrake system is exactly the same - more or less on your as what's on your light truck or car. The system will not fail and there was one more piece I wanted to say about it, yes, - the other piece about it is all of these things are the same: you have service breaks, you have parking brake, and you have emergency brakes on both hydraulic system and an airbrake system. The only difference on an airbrake system is the power source. So you have air pressure to operate the service brakes and you have large powerful springs to operate the parking brakes and the emergency brake. So the only difference between a hydraulic braking system and an airbrake system is the power source; otherwise the two systems are almost identical. The way that they operate is a little bit different, but for the most part they work fundamentally the same. And it's a little weird in the beginning, but for the most part, as I said at the outset of the live stream here, the problem with air brake systems is that the course is designed to teach you about an air brake system designed in the 1970s, and air brake systems have evolved and they just simply won't fail in this day and age. The last failing of an airbrake system was the manual slack adjusters because drivers had to get under the vehicle and actually, physically manually adjust the brakes on air brake system. In the mid-1990s, authorities came up with automatic slack adjusters and they were mandated that they had to be fitted on all new vehicles after 1996. And it's nigh impossible to find manual slack adjusters in the day-and-age of o airbrake systems. So that's a quick overview of air brakes. If you have any questions at all, leave a comment down in the comment section there. Leave me a question. There's lots of information here on the channel about air brakes. There's a playlist called air brakes that will give you lots of great information about air brakes. If you're going for a CDL license, whether it's tractor-trailer, a bus, a truck, or if you've got a new RV unit you're going to need an air brake ticket. As well, tomorrow, 12 February 2017, I will have the airbrake course ready over at my website, which you can go over and you can purchase. And have a look at that as well. So I will leave a link for the airbrake course down in the description. Check that out if you're working towards getting your CDL license. So thanks very much for attending and showing up today and giving of your time. And if you're thinking about getting a CDL license or you're working towards your commercial driver's license or your air brake ticket good luck with that. I'm Rick with Smart Drive Test - thanks so much for watching. Good luck on your road test. And remember, pick the best answer not necessarily the right answer.