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Semi-trucks barrel down highways daily, loaded down with heavy cargo. If a driver needs to slow down or come to a stop, it’s the brakes they rely on to keep everyone safe. With well-maintained brake pads, semi-trucks can operate more safely and efficiently, driving up fleet productivity.
While brakes are essential for any semi-truck, they’re easy to overlook during maintenance. In fact, truck tires and brake systems are the most common issues in fatal crashes involving large trucks. Good brake pad upkeep saves lives, extends brake life, and minimizes downtime. If you want to keep your fleet productive, cost-effective, and safe on the road, you need to take a look at every truck’s brake pads.
With semi-trucks weighing so much and traveling at highway speeds, traditional hydraulic brakes aren’t enough. Hydraulic fluid can leak out, leaving a vehicle with no braking power. Large trucks use air brake systems to overcome this issue.
Instead of relying on fluid, semis use compressed air to activate the braking system. When drivers press the brake pedal, air flows into the brake chamber, pushing a diaphragm that applies force to the brake pads. This slows the vehicle without relying on a limited substance — even if a minor leak occurs, the system can still use compressed air to stop the vehicle.
Brake pads are the components that apply friction to the brake drums. This friction decelerates the truck as the driver presses on the brakes. All that friction leads to eventual wear. Over time, heavy loads, frequent braking, and long hauls will wear down the brake pads. When they wear too low, they can’t perform effectively.
Regular brake pad maintenance is critical for proper fleet management. Fit brake pad checks into your routine maintenance schedule and pre-trip inspections. The more miles and weight brake pads see, the more frequently they need replacing. Check the brake pad wear rating for a recommended replacement time, but remember to keep an eye on the brake pads yourself in case they wear out early.
Commercial vehicles with air brake systems should replace their brake pads when they hit 1.6 millimeters to 6.4 millimeters, depending on the vehicle type. For example, hydraulic disks, drums, and electric brakes should never fall below 1.6 millimeters, while air disc brakes need replacing at 3.2 millimeters. Measure brake pads with every pre-trip inspection to catch them before they wear too low.
Here are the signs to look for during your inspection or while driving:
If you’re concerned about the vehicle’s brake pads, measure them. Replace thin pads to stay Department of Transportation (DOT) compliant. If your drivers get caught during one of the several DOT inspection levels, they need to have a system that meets regulations.
Most semi-trucks use air brakes, which have no brake fluid. They use compressed air to stop the vehicle.
Some medium-duty and specialized trucks use hydraulic braking systems. These systems rely on brake fluid to create the force needed to stop the vehicle. Typically, larger vehicles used for commercial tasks will use DOT 4 brake fluid. DOT 4 has a higher boiling point than DOT 3, which is needed for heavy-duty work. Braking generates heat — the heavier the load and the more aggressive the haul, the more heat the brakes generate. If you use a lower DOT fluid, it could hit its boiling point and vaporize. Going with at least a DOT 4 prevents brake fluid from boiling and affecting braking safety.
If it’s time to replace a vehicle’s brake pads, you have a decision to make — original equipment manufacturer (OEM) or aftermarket pads?
OEM brake pads are produced by the original semi-truck manufacturer or an authorized supplier. They meet the exact factory specifications of each model. Going with OEM parts ensures you get compatible brake pads. You can invest in these pads knowing they’re tested to meet manufacturer standards, reducing the risk of brake system issues.
Since OEM brake pads are from the manufacturer, fleet managers can expect predictable wear patterns and performance. This consistency makes maintenance scheduling simpler. While OEM brake pads are reliable, they’re more expensive than aftermarket parts. Weigh their higher cost with manufacturer-approved specs.
Third parties produce aftermarket brake pads. They come in a much wider range of materials and performance levels. If you’re looking for flexibility and affordability, choose aftermarket parts. Since they’re third-party, you can customize aftermarket parts to fit unique driving conditions. Get brake pads suited for extreme temperatures, heavy loads, or longer service lives.
The main drawback of aftermarket parts is their third-party status. They might void your warranty with the semi-truck manufacturer. Plus, if there are performance issues, you can’t turn to the manufacturer for help. Consider your options carefully to find the safest, most cost-effective option for your fleet.
Commercial drivers must remain compliant with the DOT and the Federal Motor Carrier Safety Administration (FMCSA). Both of these agencies regulate brake pads to maintain road safety. DOT uses the Commercial Vehicle Safety Alliance (CVSA) braking levels for inspections. Commercial vehicles are subject to routine vehicle inspections depending on their task.
A qualified brake inspector will check your semi-truck brake system for:
If there is a compliance issue, inspectors may fine drivers or companies. Violations can also lead to higher insurance costs and out-of-service violations. Stay proactive with your maintenance to avoid brake inspection issues.
Regular maintenance and inspections keep your semi-truck brake pads in good condition. Avoid brake-related downtime with this maintenance checklist:
Divers should conduct pre-trip inspections to ensure brake pads have no wear or warning signs before they head out. Fleet managers and drivers can keep a record of semi-truck brake pad thickness, replacing pads before they get too low. Your team should also look for air leaks, uneven wear, and caliper issues as part of their regular inspections.
Fleet managers can promote better braking practices to protect pad life. Advise drivers to:
While drivers can spot basic brake pad issues during pre-trip inspections, every truck needs regular professional servicing. Work with a professional maintenance provider to ensure your brake systems and other components are at their best. Experts will know how to spot the warning signs and extend vehicle life for a more efficient fleet.
Brake pad maintenance isn’t just about compliance. You need reliable brake pads to keep drivers safe and productive while on the road. At Thompson Truck Source, we understand the challenges fleet managers face. We’ve been servicing the trucking industry for over 60 years. Unlike national chains, we’re local. We know your business, your routes, and the demands your trucks face every day.
Whether you need reliable brake pads, expert commercial truck inspections, or emergency system repairs, we’re here to help. We offer fast, trustworthy service that minimizes downtime and helps you stay compliant. Contact Thompson Truck Source today to schedule your next Alabama or Florida service.