How to Prevent Brake Fade in Heavy-Duty Trucks

Brake fade is a serious concern for heavy-duty truck drivers, especially when hauling substantial loads or navigating long downhill grades. This phenomenon occurs when brakes overheat, reducing their effectiveness and putting the driver, cargo, and everyone on the road at risk. Let’s break down what brake fade is, how it happens and how to prevent it.

Understanding Brake Fade

At its core, brake fade happens when the braking system’s components—like brake shoes and drums or rotors—reach a temperature that compromises their ability to function. In air brake systems commonly found in heavy-duty trucks, compressed air activates the brakes. But when excessive heat builds up, it can reduce the friction between the brake shoes and drums, causing a gradual or sudden loss of braking power.

Causes of Brake Fade

• Excessive Heat: The most common cause of brake fade is overheating. When brakes are used extensively—like during steep downhill descents or heavy traffic—the friction between the brake drum and shoes generates a lot of heat. Once the temperature surpasses a certain threshold, it reduces the friction necessary to stop the vehicle effectively.
• Long Braking Periods: Holding the brakes for extended periods without giving them time to cool down can cause overheating. Continuous braking forces the system to work harder than it’s designed to, leading to brake fade.
• Worn Brake Components: Over time, brake shoes, drums, and rotors wear down. As these parts become thinner, they’re less effective at dissipating heat, which can accelerate the occurrence of brake fade. Regular wear can turn into a dangerous situation if left unchecked.
• Contaminants on Brake Linings: Oil, grease, or brake fluid leaking onto the brake shoes or drums can reduce the friction needed to stop your truck. This can exacerbate brake fade by allowing the brakes to slip or lose grip, even before overheating is an issue.

How to Prevent Brake Fade

Engine Braking

One of the best ways to prevent brake fade is by using your engine brake (also known as a jake brake) during descents. Instead of relying solely on the brakes, this method uses the engine to slow down the truck, relieving the brake system from excessive wear. By utilizing the engine’s power to control speed, you prevent the brakes from overheating.

Gear Selection

When going downhill, selecting a lower gear can significantly reduce the need for frequent braking. The engine’s resistance helps control the vehicle’s speed, taking much of the burden off the brake system. This is especially important when driving in mountainous areas or on long declines where extended braking periods are unavoidable.

Avoiding Constant Braking

Instead of riding the brake pedal, brake intermittently. This technique, known as pulse braking, allows the brakes time to cool between applications. Applying the brakes for shorter, stronger intervals helps prevent them from overheating. In contrast, constant pressure on the brake pedal builds heat and leads to quicker brake fade.

Regular Brake Inspections

Worn brake components are a leading cause of brake fade. To avoid this, it’s essential to schedule regular inspections of your truck’s brake system. Pay attention to the condition of the brake shoes, drums, rotors, and air compressor. Check for wear, cracks, or glazing on the friction surfaces. If any parts show signs of wear or damage, replace them before they fail during a critical moment.

Keeping Your Air System Dry

Moisture in the brake system can lead to brake fade, especially in colder climates. Water can collect in the air lines, freezing and blocking airflow to the brake chambers, or causing rust and corrosion over time. Ensure that your air dryer is functioning correctly to remove moisture from the system. Regularly draining the air tanks will also prevent moisture buildup.

Brake Adjustment

Slack adjusters in drum brake systems must be properly maintained and calibrated. If the slack adjuster isn’t working efficiently, the brakes may need to travel further to engage fully, causing more heat to build up in the system. Automated slack adjusters help prevent these problems, but they still need periodic checks to ensure they're functioning properly.

Upgrading Brake Materials

Choosing high-quality, heat-resistant brake shoes and drums can greatly improve your truck’s performance under stress. Some materials, like ceramic or advanced metallic linings, are better at withstanding high temperatures without compromising their frictional properties. Investing in premium brake components might be a higher upfront cost, but they reduce the likelihood of brake fade and extend the system's lifespan.

When Brake Fade Occurs

Despite all your best efforts, brake fade can still happen. If you start to experience diminished brake performance:

• Slow down: Reduce speed by downshifting and using the engine brake.
• Pull over safely: If possible, pull off the road to allow your brakes to cool down.
• Never pump the brakes: Unlike hydraulic brake systems, pumping the brakes in air brake systems can make things worse by releasing the stored compressed air needed to stop the truck.

Don’t Let Brake Fade Slow You Down

Preventing brake fade in heavy-duty trucks comes down to understanding the braking system, proper driving techniques, and regular maintenance. Using the engine brake, choosing the right gear, and ensuring all components are functioning properly are just a few ways to keep your truck’s braking system in peak condition. Remember, brake fade is preventable with the right knowledge and care.

If you require brake repairs in Nashville, Tennessee, contact West Power Services today.