Monday, May 11, 2009
SEMI TRUCK TRACTOR AIR BRAKES
Well, here again I am going to blog about semi truck air brakes but, this time I am going to talk about the tractor brakes.
I would like to start off explaining the buttons on the dash. The red button is the (tractor protection, break away) valve. This valve controls the air to the red (emergency) air line to the trailer and has nothing to do with the tractor brakes. It fills a tank on the trailer with air at the pressure shown on the dash air gauge. This air pressure releases the trailer spring loaded parking brakes so that the trailer wheels are free to roll.
The yellow valve controls the spring parking brakes on the tractor and has nothing to do with the trailer. Each valve is independent of the other even though they are both together on the dash. When you pull the yellow valve it engages the tractor parking brakes. Unless there have been some changes that I don't know about you can push each valve in independently one at a time or you can push them both in at once. If you push them both in then that will release both the tractor and the trailer parking brakes.
When you charge the trailer system with air then the red emergency line is pressurized and is kept that way all the time the red valve is pushed in. The blue (service) line has no air in it until you either push the foot valve or pull the trailer hand valve. The pressure in the blue line will only have as much pressure as what is being used to apply the trailer brakes. A truck does not release any air in any line to apply the trailer brakes. It is all done with pressure from the tractor and the tank on the trailer once the valve on the trailer tank is actuated. When you pull the trailer hand valve that only operates the trailer brakes. The only way to operate all the brakes on the vehicle is to use the foot valve.
Never use the hand valve as a parking brake. Pull the red emergency and the yellow tractor parking brake valves on the dash whenever you wish to park no matter how short a time that may be. Never use just the trailer brakes to stop a vehicle as that will heat up the brakes on the trailer and possibly cause other problems.
If you have the trailer emergency line charged and you remove the glad hand connecting to the trailer then you will lose air in that line and the trailer spring brakes and the service brakes which have no spring brakes on them will apply. When the emergency line loses pressure then the valve on the trailer tank allows air from the tank to apply the brakes and that will keep the brakes applied until that tank loses air pressure then those without spring brakes will release. The spring brakes will remain applied even though the trailer tank loses air because they are spring loaded and the spring pressure will keep the brakes applied. The valve will not allow any air to be removed from the tank except that which applies the brakes. It puts pressure into the tank but the valve is one way only and won't let any air come back out of the line. If, after you remove the glad hand, you should happen to hear air coming out of the line then the valve is defective and needs to be replaced.
I realize that I said I was going to talk about tractor brakes and spoke a lot about the trailer. That is because they are both related and are both operated from the tractor so I can hardly speak of one without speaking of the other.
I am going to publish this blog now even though I may add a bit more to it later.
If you would like more information on how brakes work from the people who make the parts for the brakes then go.to this link. http://forums.aths.org/Attachment20808.aspx You will find the Bendix Air Brake Handbook. It explains it the best of what I have found on the web. The description starts on page 5. It will take a bit to load because it is 60 some pages.
Donald Fout
mrdon636@aol.com
Tuesday, May 5, 2009
BE A BOBBLE HEAD
5/5/09
OPINING OPINER'S OPININGS
To opine means to give an opinion. Since I am a very opinionated person I figured that I can't say it enough. Who is this whining opiner?
My name is Don Fout. I am a truck driver who has been driving trucks since 1954 and been over the road since 1957. I am known as the "Chi" Guy w / Necktie on the CB. Although this may sound redundant, sometimes redundancy is the best teacher and the best way to get things across, although it may not always work.
I am also a machinist, mechanic, welder and general all around "Jack Of All Trades." I am not an engineer or such and have no real proof that the things that I speak of are actual fact. These are only my opinions. They are presented here to try to make you think and analyze them for yourself.
Donald Fout"Chi Guy" w/Necktie (CB Handle)
BE A BOBBLE HEAD
I know that you have seen the times that a vehicle has been all over the road. You may have even wondered if the driver was under the influence of something but, there are times that the driver is totally unimpaired. The problem could be the wind or just the lay of the road, it may be rutted or just have a lean to it which causes the vehicle to want to wander. Not too long ago I was in a place where the wind was very strong and the gusts made it even worse.
I came upon a truck that was having a hard time staying in its own lane. It was veering so much out of it's lane that I decided not to attempt to pass it so I followed. I noticed that when we came to an area where the wind was blocked by trees that it stayed pretty well in it's own lane, so I waited until we came to an area which was bordered by a long line of trees before I passed.
Shortly after I did a voice came on the C B calling out for my company's truck. Thinking it was another of our drivers I looked around but could see none of our trucks. I answered and was told it was the truck I had just passed.
Then the driver said then was, "How do you do that?" Not knowing what he was talking about I replied, "How do I do what?" He then said, "You're empty, aren't you? How do you stay in your lane like that?" I told him that I was empty and that maybe he had something wrong with his steering. He informed me that under normal circumstances he had no problem at all but, the wind made it so he was all over the road. He said, "When you were behind me I noticed that you stayed right in your lane and then when you passed me I could see that your trailer was blown all over but, your tractor stayed right in the middle of the lane and I want to know how you do that."
I told him what I had found out what to do to correct the problem and after he tried it he told me that that made it a whole lot easier. I then thought that I might pass it on to others.
What I told him was, BE A BOBBLE HEAD. Let your head and body tell you where to steer. It will help in any situation. The easiest way to learn is to sit straight up in the seat. As you travel you will feel your head bob to the left and right. When it bobs left, steer left, when it bobs right, steer right. How much you steer depends on how much you lean.
If you are on rutted roads you may well be steering left and right and left and right in very rapid succession but, the vehicle will continue on in the middle of the lane you are in and not wander all over because you are correcting as the action takes place. The vehicle will have no chance to wander out of the lane.
The reason you lean left is because the vehicle moved right, therefore you steer left to correct. This works in any vehicle. It matters not what type or size. After a while you will not have to sit up straight and it will become second nature Thanks for taking the time to read this. I hope it will help.
Any questions or other suggestions make a comment.
Donald Fout
If you would like training in internet marketing then please visit:
www.mrdon636sstore.com
There is also our Amazon link on the page.
Don
OPINING OPINER'S OPININGS
To opine means to give an opinion. Since I am a very opinionated person I figured that I can't say it enough. Who is this whining opiner?
My name is Don Fout. I am a truck driver who has been driving trucks since 1954 and been over the road since 1957. I am known as the "Chi" Guy w / Necktie on the CB. Although this may sound redundant, sometimes redundancy is the best teacher and the best way to get things across, although it may not always work.
I am also a machinist, mechanic, welder and general all around "Jack Of All Trades." I am not an engineer or such and have no real proof that the things that I speak of are actual fact. These are only my opinions. They are presented here to try to make you think and analyze them for yourself.
Donald Fout"Chi Guy" w/Necktie (CB Handle)
BE A BOBBLE HEAD
I know that you have seen the times that a vehicle has been all over the road. You may have even wondered if the driver was under the influence of something but, there are times that the driver is totally unimpaired. The problem could be the wind or just the lay of the road, it may be rutted or just have a lean to it which causes the vehicle to want to wander. Not too long ago I was in a place where the wind was very strong and the gusts made it even worse.
I came upon a truck that was having a hard time staying in its own lane. It was veering so much out of it's lane that I decided not to attempt to pass it so I followed. I noticed that when we came to an area where the wind was blocked by trees that it stayed pretty well in it's own lane, so I waited until we came to an area which was bordered by a long line of trees before I passed.
Shortly after I did a voice came on the C B calling out for my company's truck. Thinking it was another of our drivers I looked around but could see none of our trucks. I answered and was told it was the truck I had just passed.
Then the driver said then was, "How do you do that?" Not knowing what he was talking about I replied, "How do I do what?" He then said, "You're empty, aren't you? How do you stay in your lane like that?" I told him that I was empty and that maybe he had something wrong with his steering. He informed me that under normal circumstances he had no problem at all but, the wind made it so he was all over the road. He said, "When you were behind me I noticed that you stayed right in your lane and then when you passed me I could see that your trailer was blown all over but, your tractor stayed right in the middle of the lane and I want to know how you do that."
I told him what I had found out what to do to correct the problem and after he tried it he told me that that made it a whole lot easier. I then thought that I might pass it on to others.
What I told him was, BE A BOBBLE HEAD. Let your head and body tell you where to steer. It will help in any situation. The easiest way to learn is to sit straight up in the seat. As you travel you will feel your head bob to the left and right. When it bobs left, steer left, when it bobs right, steer right. How much you steer depends on how much you lean.
If you are on rutted roads you may well be steering left and right and left and right in very rapid succession but, the vehicle will continue on in the middle of the lane you are in and not wander all over because you are correcting as the action takes place. The vehicle will have no chance to wander out of the lane.
The reason you lean left is because the vehicle moved right, therefore you steer left to correct. This works in any vehicle. It matters not what type or size. After a while you will not have to sit up straight and it will become second nature Thanks for taking the time to read this. I hope it will help.
Any questions or other suggestions make a comment.
Donald Fout
If you would like training in internet marketing then please visit:
www.mrdon636sstore.com
There is also our Amazon link on the page.
Don
Friday, May 1, 2009
semi-truck trailer air brake system
OK Before I start I would like to say that I don't know anything about blogging. I was told that I should do this just so I can get the hang of it. The things that I would like to talk about the many and varied. I would like to talk about trucks and their safety features and many other things pertaining to trucks since I was a over-the-road truck driver most of my life. I am also known as jack of all trades. They also call me a tinker because I like to take things apart that don't work and make them work even if I don't need them just to see if I can.
The first thing I am going to talk about is truck brakes since there seems to be quite a misconception as to how they work. I have been reading some articles on the web lately which are supposed to be explaining how they work and they are not correct and yet these articles are read by many people. I would like to set the record straight and get people to understand how they do work. Let me explain that I am not too well versed on all the advancements made in the braking systems of today but as far as I know they still work in the same manner as the older brakes with some improvements.
Many people are under the misconception that when you put air pressure into the lines that releases the brakes. To make the brakes apply you release pressure out of that line. That is not correct unless you are talking about only the spring loaded parking brakes. The service brakes are a whole different matter and are a separate system from the parking brakes.
When you push in the "Emergency" "Tractor Protection" valve on the dash that does pressurize the line called the emergency line and it does fill a tank on the trailer . This line does does not release any brakes other than the parking brake which is a spring loaded brake and the air pressure is used to compress a spring to release those brakes. The air in the tank is used to apply the service brake but only when the air in the emergency line is expelled or released. That is so that in the event that you should have the trailer separate from the tractor and the emergency line should come apart then the trailer brakes will apply stopping the trailer even without any spring loaded brakes. The reason I say that is because many units have spring parking brakes on only one axle and not on both.
If you pull out the parking brake valve on the dash that only applies the parking brakes on the tractor. It has nothing to do with the parking brakes on the trailer. So, if you want maximum braking power while parked then pull both valves. That will apply the parking brakes on both the tractor and the trailer and until they leak off will apply air to the service brakes on the trailer if they are not equipped with spring parking brakes.
Maybe I should break this apart as well as I can because it may seem confusing to some so, I will explain the spring loaded parking brake on the trailer and then I will explain the service brake on the trailer. It is sometimes hard for a person who knows about something to explain it to someone who does not because the person who does not cannot understand some of the things that it person who knows says.
When it comes to the spring loaded parking brakes on a trailer. Air pressure is applied to the diaphragm inside the canister to push against the spring thereby releasing the brake. When there is no air against the diaphragm the spring pushes upon the rod which goes through the bottom of the chamber to push against the service brake diaphragm the same way as air pressure when you apply the brakes from the tractor but, at this time there is no air pressure against the service brake diaphragm, only the pressure of the spring pushing against the rod pushing the diaphragm down to apply the brake. When you again apply pressure to the spring brake diaphragm it collapses the spring thereby releasing the brake.
When it comes to the service brakes on a trailer. Remembering that the spring brake is now released because there is air pressure applied to that diaphragm. This air is contained in the spring brake canister and is separated from the service side by o-rings on the shaft from the spring brake. At this time all brakes are released and the wheel can roll freely.
When you apply pressure to the service line which is the line from the foot valve on the tractor then air is applied to the service brake diaphragm and pushes the push rod connected to the slack adjuster thereby applying the brakes. This air is separated from the air in the spring brake canister by the same o-rings on the spring brake shaft. When you release the foot brake then you hear the air being expelled through the exhaust port but only the air from the service brake canister and the brakes are released.
That is enough for this blog. I still have to explain the brakes on the tractor and how they are the same and yet different in some ways.
The first thing I am going to talk about is truck brakes since there seems to be quite a misconception as to how they work. I have been reading some articles on the web lately which are supposed to be explaining how they work and they are not correct and yet these articles are read by many people. I would like to set the record straight and get people to understand how they do work. Let me explain that I am not too well versed on all the advancements made in the braking systems of today but as far as I know they still work in the same manner as the older brakes with some improvements.
Many people are under the misconception that when you put air pressure into the lines that releases the brakes. To make the brakes apply you release pressure out of that line. That is not correct unless you are talking about only the spring loaded parking brakes. The service brakes are a whole different matter and are a separate system from the parking brakes.
When you push in the "Emergency" "Tractor Protection" valve on the dash that does pressurize the line called the emergency line and it does fill a tank on the trailer . This line does does not release any brakes other than the parking brake which is a spring loaded brake and the air pressure is used to compress a spring to release those brakes. The air in the tank is used to apply the service brake but only when the air in the emergency line is expelled or released. That is so that in the event that you should have the trailer separate from the tractor and the emergency line should come apart then the trailer brakes will apply stopping the trailer even without any spring loaded brakes. The reason I say that is because many units have spring parking brakes on only one axle and not on both.
If you pull out the parking brake valve on the dash that only applies the parking brakes on the tractor. It has nothing to do with the parking brakes on the trailer. So, if you want maximum braking power while parked then pull both valves. That will apply the parking brakes on both the tractor and the trailer and until they leak off will apply air to the service brakes on the trailer if they are not equipped with spring parking brakes.
Maybe I should break this apart as well as I can because it may seem confusing to some so, I will explain the spring loaded parking brake on the trailer and then I will explain the service brake on the trailer. It is sometimes hard for a person who knows about something to explain it to someone who does not because the person who does not cannot understand some of the things that it person who knows says.
When it comes to the spring loaded parking brakes on a trailer. Air pressure is applied to the diaphragm inside the canister to push against the spring thereby releasing the brake. When there is no air against the diaphragm the spring pushes upon the rod which goes through the bottom of the chamber to push against the service brake diaphragm the same way as air pressure when you apply the brakes from the tractor but, at this time there is no air pressure against the service brake diaphragm, only the pressure of the spring pushing against the rod pushing the diaphragm down to apply the brake. When you again apply pressure to the spring brake diaphragm it collapses the spring thereby releasing the brake.
When it comes to the service brakes on a trailer. Remembering that the spring brake is now released because there is air pressure applied to that diaphragm. This air is contained in the spring brake canister and is separated from the service side by o-rings on the shaft from the spring brake. At this time all brakes are released and the wheel can roll freely.
When you apply pressure to the service line which is the line from the foot valve on the tractor then air is applied to the service brake diaphragm and pushes the push rod connected to the slack adjuster thereby applying the brakes. This air is separated from the air in the spring brake canister by the same o-rings on the spring brake shaft. When you release the foot brake then you hear the air being expelled through the exhaust port but only the air from the service brake canister and the brakes are released.
That is enough for this blog. I still have to explain the brakes on the tractor and how they are the same and yet different in some ways.
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