Winter Edition of the Western Canada Highway News
Our Maintenance Manager Alex Downey publishes a quarterly article in Western Canada Highway News magazine. Below is an excerpt from his article published in the Winter Edition starting on page 67.
Pump the Brakes
Let’s talk about air brakes! Whether you’re new to the commercial driver’s seat or you’ve been on the open road for years, it’s always a good time to think about the components that slow the roll of your truck and trailer. It’s important to familiarize yourself with the basics, so here’s a little refresher.
It all starts with your air compressor building the appropriate amount of air to fill your tanks. Many essential components on your equipment are likely air-actuated, so it’s imperative that your tanks are able to hold enough air to make these systems work reliably. Too much air loss caused by a leak can stop the function of your brakes, suspension, and your truck’s transmission, making for a very unsafe situation. When the driver presses the brake pedal, it opens a valve that allows air to flow from the tanks into the brake chambers or ‘brake pots,’ as some would say. Each wheel has a brake chamber, which consists of a diaphragm that moves when air enters the chamber. As air fills the chamber, it pushes the diaphragm outward, creating force. This force moves a rod that applies your brake shoes (for drum brakes) or pads (for disk brakes), slowing and stopping the wheel.
As a safety feature, many air brake systems include spring brakes. These are held in a released position by air pressure. If air pressure is lost, the springs automatically engage the brakes to prevent the vehicle from rolling.
Once you’ve built up your air, hooked it to your trailer, and are in pre-trip mode, you should make a six-pack brake application. What is a six-pack, anyway? This is an obvious daily routine to some drivers, but I have surprisingly turned more than one veteran driver onto this useful practice.
Air the truck up to maximum pressure and make three hard brake applications. When you make three hard brake applications, you will be below 90 psi, so pump the system back up to maximum pressure again. And again, make three more full hard brake applications. That’s called a six-pack! This shows the driver that the brakes are operating properly and lets you check for any leaks in the brake system. It also enhances the responsiveness of your brakes by equalizing pressure and adjusting your slacks. This works on your trailer, too.
See the full article at Western Canada Highway News.
See Alex’s Summer Edition Looking for a Problem – Pre & Post Trips
