There are a lot of myths out there about drum brakes. These can lead to unsafe practices, costly repairs, and unnecessary downtime. Let’s break down the top five myths so you can keep your air brakes in top shape and your rig on the road.
Myth 1: Air Brakes are Maintenance-Free
One of the most common misconceptions in the industry is that air brakes require little to no maintenance. Some drivers and operators assume that air brakes are less prone to issues since they don't rely on fluids like hydraulic systems. Well, that's just plain wrong.
Fact
Air brakes need regular inspections and adjustments. Components like air compressors, slack adjusters, and S-cams must be adequately lubricated, aligned, and checked for wear. Compressed air systems are susceptible to moisture, which can lead to frozen lines in cold weather, so air dryers need attention, too.
Without proper heavy-duty brake maintenance, these components can fail, leading to brake malfunction or, worse, an accident.
Myth 2: Heavy-Duty Brakes Don’t Overheat
The idea that air brakes in big rigs are immune to overheating might initially seem plausible. After all, air brakes don’t rely on fluid that can boil under extreme heat, right? Wrong again.
Fact
Even though they function differently from hydraulic systems, air brake systems can still overheat. Components like brake shoes and drums are subject to intense friction, especially during long downhill drives or heavy loads. This friction generates heat, and if brakes are poorly adjusted or worn out, they can overheat, reducing braking power.
Always inspect and replace worn-out brake drums and shoes to maintain optimal performance.
Myth 3: Brake Fade Only Happens in Hot Climates
Some operators think brake fade—the reduction of stopping power—only occurs in hot weather or during extreme braking. They believe they're in the clear as long as they aren’t hauling through deserts.
Fact
Brake fade can happen anytime, especially during long downhill hauls or overloading the truck. It occurs when brake drums and shoes get too hot, reducing friction and, thus, braking ability. This is why drivers are encouraged to use engine or Jake brakes to assist in deceleration. Proper load distribution and regular brake checks will help mitigate this issue.
Myth 4: Automatic Slack Adjusters Don’t Need Attention
Many drivers think automatic slack adjusters (ASAs) mean you can forget about brake adjustments. Once installed, they assume the system adjusts itself without any oversight.
Fact
While ASAs do adjust automatically, they can still fail. Over time, these adjusters can become misaligned or wear out, causing improper brake application. Regularly inspecting your slack adjusters to ensure they’re functioning correctly is crucial.
Manual slack adjusters need adjustment more frequently, but ASAs need periodic checks to ensure they’re keeping your brakes within the right tolerance.
Myth 5: If One Brake Fails, the Others Will Compensate
This is a dangerous myth that can have fatal consequences. Some drivers assume that if one brake system fails, the others will pick up the slack. After all, heavy-duty rigs have complex systems with multiple axles and brake sets, don’t they?
Fact
Every brake in your system is crucial. If one brake fails, it puts a more significant load on the others, leading to uneven wear and potential failure of the entire system. Heavy-duty trucks rely on all brakes functioning together to provide safe stopping power.
If even one is out of commission, you’re setting yourself up for an increased stopping distance and possible brake failure when you need it most.
Conclusion
Heavy-duty brake systems are complex, and myths surrounding their care can lead to unsafe practices. Regular inspections, proper maintenance of air compressors, slack adjusters, and brake drums, and an understanding of how your brakes work are essential to keeping your rig safe.
Don’t fall for these myths—stay informed and stay safe on the road!
