Optimizing Air Disc Brake Performance

Air disc brakes (ADBs) offer significant advantages in performance and maintenance, but realizing their full potential requires consistent and proper care. To maximize the value and extend the life of ADB pads and rotors, fleets and owner-operators can adopt specific preventive maintenance practices. These straightforward actions help protect the initial investment in ADB technology and ensure continued safety and performance.

Key Highlights

The relationship between the brake pad and rotor, known as the friction couple, is critical for balanced wear and optimal performance.
Using like-for-like, Original Equipment (OE) quality replacement parts is strongly recommended to maintain system integrity and stopping power.
Regular inspections of friction wear are essential for preserving the life of pads and rotors, even though ADBs do not require routine lubrication.
Advanced wear-sensing systems provide real-time data that enables proactive maintenance scheduling, helping to prevent costly repairs and unexpected downtime.

Understanding the Friction Couple

A key to Air Disc Brake longevity is the relationship between the brake pads and the rotor. This friction couple works as a system to convert the vehicle’s kinetic energy into heat, which is then dissipated. For optimal results, the rotor’s metallurgy and the pad’s formulation must be intentionally matched. OE suppliers like Bendix engineer these components to work together, ensuring not just effective stopping power but also balanced wear. This approach protects the life of the rotor. In contrast, some non-OE suppliers may offer pads that wear longer at the expense of faster rotor degradation.

Selecting the Right Replacement Parts

Choosing the correct friction material is vital for maintaining intended ADB performance. Factors such as fleet type, vehicle configuration, and duty cycle influence which pad is most suitable. When replacing pads, using lower-quality materials can lead to significant performance degradation. It is important to note that not all aftermarket pads comply with Federal Motor Vehicle Safety Standard (FMVSS) 121, with some shown to increase stopping distances. Bendix advises like-for-like replacements to preserve the brake system’s integrity.

Furthermore, environmental regulations play a role in part selection. The EPA’s Copper-Free Brake Initiative, effective January 1, 2025, mandates that friction materials contain less than 0.5% copper. In response, Bendix introduced the BX277™ OE-level pad to meet these standards.

The Importance of Regular Inspections

While ADBs are lubricated for life and do not need grease fittings, they still demand regular checks, particularly as friction material nears its end-of-life. The primary focus of ADB preventive maintenance should be inspecting for friction wear to prevent potential damage to the rotor.

To simplify this process, Bendix provides a pad and rotor wear gauge that allows technicians to measure component thickness without disassembly. For vehicles operating in debris-prone environments, installing ADB pad shields can prevent foreign materials from getting lodged in the brakes and causing damage.

Leveraging Technology for Smarter Maintenance

Modern technology offers a more proactive, data-driven approach to ADB maintenance beyond visual checks. Bendix’s iSense™ and iSense™ Pro brake wear sensing systems give fleets real-time insight into brake conditions. The iSense system sends an alert through telematics when pads are close to needing replacement.

The more advanced iSense™ Pro system continuously monitors pad and rotor wear at each wheel-end, reporting the remaining life as a percentage. This detailed data allows fleets to schedule maintenance proactively. According to Keith McComsey, Bendix technical sales lead, iSense Pro also enables cross-axle comparisons. A significant difference in wear—20% or more—between two sides of an axle can alert technicians to investigate potential issues, preventing costly damage and downtime. This proactive maintenance also supports the performance of advanced driver assistance systems (ADAS) that rely on proper brake function.