Thursday, April 30, 2009

TRUCK AIR BRAKE SYSTEM

Am I Right or Am I Wrong?



OK, I'm going to start blogging. I don't know what I'm doing but, I'm going to start blogging. I'm going to talk about semi-truck air brakes.



I have been an over-the-road truck driver most of my adult life. I started driving in 1954 in the city of Chicago and went over the road in 1957. I am now retired and no longer drive over the road.



In that time I have seen many things. Some of them almost made me sick. I have driven trucks that were barely legal to be on the road. I know, you probably say that I should not have driven them. Well, that may be true but, when you are supporting a family and the boss tells you to take that truck it does not matter that it needs work. As long as it is legal then you have to go with it even though it may not be the safest thing to do.

The thing to do is look for a company which maintains their equipment properly. If you are with one now then you don't know how lucky you are because there are some out there that only care about getting the freight down the road. Maybe I should not say there are such companies now since I have not been driving for some years now. But, there were. I have never owned a truck of my own, I always drove for someone else.



One of the worst problems that I faced was faulty brakes. It seemed like the management felt that as long as the truck would go down the road and stop at all then that was good enough. I'm not saying that all of them were that way but there were a few over the years and that is why I would like to talk about truck brakes.



Over the years I have found that many in trucking do not fully understand how air brakes on trucks work. I have found that there are quite a few that feel the brakes work just like they do on a railroad car and they do not. A railroad car has only one brake line and a truck has two. One is the emergency (supply) line and the other is the service (control) line.



It is true that the emergency line does use air pressure to release the brakes but, those are only the spring loaded parking brakes. The parking brakes are released when air is applied to a chamber with a diaphragm and a spring and the air collapses that spring to release the brakes.


If you would like to read about truck air brakes and how they work written by the people who make the parts for the system then follow this link: http://forums.aths.org/Attachment20808.aspx
It will take you to the Bendix Air Brake Handbook which explains all of the systems for trucks and their components. It takes a while to load because the handbook is sixty some pages long but, it is well worth it.