Brake pads are made by blending a precise mixture of fibers, metals, abrasives, and binding resins, then pressing that mixture onto a steel backing plate under high heat and pressure. The process transforms loose powders and fibers into a dense, heat-resistant friction material capable of stopping a vehicle thousands of times before wearing out. While the basic steps are consistent across manufacturers, the specific ingredients and techniques vary depending on whether the pad is semi-metallic, ceramic, or organic.
What Goes Into the Friction Material
Every brake pad starts as a recipe of raw materials, and that recipe determines how the pad performs, how long it lasts, and how much noise it makes. There are three main families of brake pads, each built from different core ingredients.
Semi-metallic pads contain between 30% and 70% metal by weight. That metal component is typically iron, steel, or copper in the form of fibers and powders, combined with graphite as a lubricant and various filler materials. These pads handle heat well and offer strong stopping power, which is why they’re common on trucks, performance cars, and vehicles that tow heavy loads.
Ceramic pads use a composite of ceramic fibers, ceramic powders, and non-ferrous fillers held together in a resin matrix. The ceramic portion can include potassium titanate fibers for reinforcement and zirconia or alumina as abrasives. Small amounts of copper fiber have traditionally been added for heat transfer, though that’s changing due to environmental regulations. Ceramic pads produce less dust and noise than semi-metallic options and are typically found on premium vehicles.
Organic pads (sometimes called NAO, for non-asbestos organic) rely on materials like rubber, glass, Kevlar, and carbon compounds bound with resin. They’re the softest and quietest option but wear faster and don’t handle extreme heat as well.
Regardless of type, nearly all brake pads use phenolic resin as the primary binder. This thermosetting plastic melts during manufacturing to flow through the mixture and lock everything together as it hardens. Some formulations substitute silicone, rubber, or epoxy resins for specific applications.
Mixing the Ingredients
The first manufacturing step is blending all the raw components into a homogeneous mixture. This happens in industrial mixers equipped with a central rotating shaft that moves materials in a figure-eight pattern while separate blender blades break up clumps and distribute fibers evenly throughout the batch.
Timing is critical during mixing. Each type of fiber has what manufacturers call an “opening time,” a window when the fiber reaches its maximum useful length. If the fibers spend too long in the mixer, they shorten and lose their ability to reinforce the finished pad. Too little time, and the mixture isn’t uniform. Getting this balance right is one of the factors that separates a well-made pad from a poorly made one.
Pressing the Pad Together
Once the mixture is ready, it’s loaded into a mold along with the steel backing plate and pressed under high heat. This step, called hot pressing, does two things simultaneously: the pressure compacts the loose material into a dense block, and the heat (around 150°C) melts the resin binders so they flow through the mixture and bond everything into a single solid unit.
The press doesn’t simply clamp down and hold. It cycles through pressing and releasing stages over a period of five to seven minutes, depending on the formula. Each release allows trapped gases to escape from the material. Without these venting cycles, gas pockets would create weak spots in the finished pad.
This is also the stage where the friction material bonds to the steel backing plate. Manufacturers use two complementary approaches. The backing plate is coated with a resin adhesive that chemically bonds to the friction material as it cures. At the same time, the plate has holes or a welded mesh structure that the molten friction material flows into, creating a mechanical interlock. That physical connection matters because adhesive bonds can degrade at the high temperatures brakes generate during hard stops. The mechanical interlocking provides shear resistance that doesn’t depend on chemical adhesion alone.
Curing in the Oven
After pressing, the pads move to curing ovens where the resin completes its chemical transformation. This process, called polymerization, finishes hardening the binder throughout the full thickness of the pad, not just at the surfaces that contacted the hot press. The ovens run through a programmed cycle of different temperatures, and the pads pass through each stage for a set duration. Any remaining volatile compounds burn off during this phase, leaving behind a fully compacted, stable friction material.
Scorching the Surface
The final heat treatment is the most intense. Called scorching, it exposes the pad’s friction surface to temperatures around 700°C for anywhere from 15 seconds to a few minutes. This heat is delivered either by pressing the pad against a hot plate or by infrared irradiation.
At these extreme temperatures, part of the phenolic resin at the surface decomposes, fundamentally changing the surface properties of the material. This serves a practical purpose: it burns away organic compounds that would otherwise vaporize the first time a driver hits the brakes, creating a gas layer between the pad and rotor that reduces stopping power. That phenomenon, sometimes called “green fade,” is what you experience when brand-new pads feel weak before they’re broken in. Scorched pads are essentially pre-broken-in at the factory. Research has also shown that scorching reduces the pad’s wear rate and lowers the amount of particulate it releases during use. Because the process is expensive and requires precise control, not all manufacturers include it.
Finishing and Noise Control
After heat treatment, pads go through finishing steps. The friction surface is ground to its final dimensions and flatness. Slots or chamfers may be cut into the surface to help channel away dust, water, and gases during braking.
Many pads then receive a shim on the back of the steel plate. These aren’t simple stickers. Quality shims use a multi-layered construction of varying grades of metal, viscoelastic polymers, elastomeric rubbers, fiberglass, and bonding materials. A high-performance shim might be carbon steel coated on both sides with nitrile rubber. The shim’s job is to dampen the vibrations between the pad and the brake caliper that cause squealing. The specific layering and materials are engineered to match the resonant frequencies of a given brake system, which is why aftermarket pads sometimes squeal when OEM pads didn’t.
How Pads Are Tested
Before a brake pad formula reaches production, it goes through extensive validation. Full-scale brake dynamometers simulate real driving conditions, running the pads through standardized sequences that test cold stops, high-speed stops, repeated hard stops to induce fade, and recovery after overheating. The SAE J2430 procedure is one widely used testing protocol that evaluates friction consistency, fade resistance, and recovery behavior across these conditions.
Pads that fail typically do so on hot performance criteria, meaning they lose too much stopping power when temperatures climb during aggressive or repeated braking. Manufacturers also examine the pad surfaces after testing using electron microscopy to study the friction layer that forms where the pad meets the rotor. The structure and chemistry of that layer directly determine how the pad wears and how consistently it grips.
The Shift Away From Copper
One of the biggest changes in brake pad manufacturing over the past decade is the elimination of copper. Copper fibers were a staple ingredient because they transfer heat efficiently and stabilize friction at high temperatures. But copper dust washes off roads into waterways, where even small concentrations are toxic to aquatic life. Under the U.S. EPA’s Copper-Free Brake Initiative, pads were required to contain less than 5% copper by weight starting in 2021, dropping to just 0.5% by 2025. Manufacturers have reformulated using alternatives like iron fibers, tin, and proprietary ceramic blends. Developing copper-free formulas that match the performance of older recipes has been one of the industry’s more significant engineering challenges, particularly for ceramic pads that relied on copper fiber for thermal management.