KANANASKIS, Alta. – If you want to get from Point A to Point B, it helps to be able to stop when you get to the final destination.
A panel of experts was assembled at the Canadian Transportation Equipment Association’s 43rd manufacturer’s conference in Kananaskis, Alta. Oct. 23-25 to deliver the straight goods on air brakes for straight trucks.
When it comes to maintenance of the air brake system it’s important to understand where the air lies in the system in order to perform proper maintenance.
“We need to be careful,” said Ron Gervais, president of the Freinmeister Group. “We need to know before we pull an air line what’s charged and what’s not. There’s 130 PSI sitting in there somewhere.”
The Technology and Maintenance Council (TMC) has developed a recommended practice to standardize the application of nylon coloured tubing by OEMs on new vehicles to reflect different sections of the air brake system. In the past, a truck moved down the assembly line and into the paint booth with the lines attached, rendering all tubing chassis black. Now, with that problem remedied, identifying the system will be easier for maintenance work.
“The coloured lines are a TMC standard so you always know where a line is leading and what it does,” added Gervais. “You should always be able to find the accessory.”
This system also makes it easier to do some basic homework, before getting underneath the truck.
“Troubleshooting from a drawing is much easier than getting down under a truck with a soapy water bottle,” said Gervais.
A lot has changed over the years in regards to air brake systems, and when spec’ing new or replacement parts it’s important to make sure all components are compatible.
“Literature is available online so don’t be shy, get help where you can get help,” noted Gervais. “Before at an order desk the only question for air dryers was do you want 12 or 24 volts.”
Today there is a larger assortment of air dryers and some will handle multiple functions in the air brake system.
“A dryer with the reservoir attached will get rid of the governor, the supply reservoir and the two single valve checks,” said Gervais.
Although the air brake standards in the US and in Canada are now identical, there remains a different standard for straight trucks and tractors.
“The demand for (straight) truck brakes is greater than tractors,” explained Dick Radlinski, of Link-Radlinski. “The main thing is a (straight) truck needs bigger front brakes than a tractor. Tractors don’t have as strict parking brake requirements because the trailer generally carries some of the responsibility.”
The discrepancy between the two systems makes any modification to a chassis from a straight truck to a tractor, or vice-versa, a very precise task.
“As far as increasing the wheelbase, if you increase the length of the lines it could effect service brake timing and parking brake timing,” said Radlinski. “Make sure you get the dynamometer certification from your axle supplier. In general, if you’re not sure the modifications will impact dynamic performance, test it.
“Basically if you modify the air system you have to time it. If you touch it, you time it.
When you take things apart and put them back together, make sure all parts of the system are working. I call it an end-of-line check.”