Debunking Heavy-Duty Brake Myths : True or False?

Myths surrounding trucking are rife. Most are harmless nonsense that you can laugh off. But others, especially those involving brakes, can lead to some extremely dangerous situations. 

Today, we’re here to set the record straight and debunk seven of the most common heavy-duty brake myths. 

Myth #1: All Air Brakes Are the Same

No, they are not. Although their basic principle remains the same—using compressed air to activate the brakes—the components and configurations may differ. For example, service chambers, pushrods, and slack adjusters will still be present but may be configured differently. 

This can help trucks that carry varying load capacities with their braking needs. What works for a local, medium-duty truck won’t work for a heavy-duty one hauling tons of cargo across the country. 

Myth #2: You Don't Need to Worry About Brake Fade in Heavy-Duty Trucks

There’s no way people actually believe this one is there? Yes, heavy-duty trucks get brake fade, and yes, you need to worry about it. Brake fade is a severe problem that can lead to equally severe consequences on the road. 

The buildup of heat is due to the friction between the brake shoes and drums, reducing its effectiveness. Routine braking system maintenance to guarantee the correct airflow will cool the brakes down during extended use and avoid these issues. 

Brake fade is just one of the issues that heavy-duty brakes can suffer from. Learn how to resolve them by checking out our article on diagnosing and repairing seven common heavy-duty brake issues.

Myth #3: Heavy-Duty Brakes Don’t Require Regular Adjustment Thanks to Automatic Slack Adjusters

While automatic slack adjusters do reduce the need for manual adjustments, they still require maintenance. If left unchecked, they can malfunction, leading to increased stopping distances, improper operation, or even complete failure. Routine inspections can spot issues in not just slack adjusters but all components and resolve them before they become big problems.

Myth #4: Drums and Discs Are Interchangeable on Any Truck

Drum and disc brakes are two very different systems. Drum brakes are commonly used in heavy-duty vehicles because they provide more braking force due to their larger surface area. However, they can suffer from heat buildup and require more maintenance. 

On the other hand, disc brakes are more efficient at heat dissipation but might offer a different level of braking force than drums in heavy-duty settings. Swapping one for the other isn't a simple task and may require substantial modifications to the brake system, making them far from interchangeable​.

Myth #5: Air Brakes Don’t Need as Much Maintenance as Hydraulic Brakes

Air brakes do not require less maintenance than their hydraulic counterparts. They probably need more because of their compressed air systems. The air compressor, air dryer, and brake lines all have their unique challenges. 

Moisture in the lines can freeze in cold weather, causing brake failure. The air dryer removes this moisture, but if it becomes clogged, it can fail, causing a domino effect of disaster.

Myth #6: Brake Retarders Replace the Need for Regular Brakes

Brake retarders, such as engine brakes or transmission retarders, assist in slowing down a truck, particularly on long descents. However, they are not a replacement for an actual braking system. Retarders reduce the wear on brakes but cannot stop a vehicle on their own. 

Relying solely on retarders without service brakes can lead to overheating and brake fade, especially on steep grades. Proper use of both systems in tandem is essential for safe driving​.

Myth #7: You Can Ignore the Air Pressure Gauge Once It’s Full

The air pressure gauge is one of the most critical instruments in your truck’s cab. It shows the pressure in the air brake system, and maintaining it within the proper range is essential for safe braking. 

Too little pressure, and the brakes won't apply correctly; too much pressure can damage the system. Drivers should regularly monitor the gauge and ensure the air compressor and other components function correctly to maintain optimal pressure levels​.

Myth #8: Brake Inspections Are Only Necessary During Annual DOT Inspections

Waiting until the annual DOT inspection to check your brakes is a dangerous practice. Brake inspections should be part of a routine maintenance schedule. Regular checks help identify issues like worn brake shoes, air leaks, and malfunctioning slack adjusters before they become severe problems. 

Being proactive with brake maintenance not only ensures safety but also reduces the risk of costly repairs and downtime​.

Conclusion

By debunking these myths, we hope to highlight the importance of understanding and maintaining your brake system. Regular maintenance, proper knowledge, and attention to detail can make all the difference in safely keeping your rig on the road.

And remember, the next time someone tells you not to worry about brake fade, show them this article.