Brake Rotor Finishing for the Automotive Aftermarket

Aftermarket disc brake rotors include high-quality auto parts that are made from new or recycled metals and machined to tight tolerances. By maintaining the right spacing between surfaces, these aftermarket brake parts ensure proper cooling and promote easy installation. Machine-balanced for trueness, many aftermarket rotors also feature an electroplated hub to prevent rust and corrosion.

For brake mechanics and aftermarket rotor manufacturers alike, it’s important for brake rotor surfaces to have a smooth surface finish. Most premium brake rotors meet roughness average (RA) requirements specified by the original equipment manufacturer (OEM). Economy brake rotors may have a rougher surface finish, but are usually ready to install right out-of-the-box.

Without the right rotor surface finish, however, disc brakes may speak or squeal. Related brake problems include poor pad seating and break-in, increased friction and wear, and buildups of brake pad glaze and surface corrosion. Fortunately, Brush Research Manufacturing (BRM) supplies a surface finishing tool that, as this YouTube video shows, is ideal for surface finishing new and re-turned rotors.

The Flex-Hone® for Rotors

The Flex-Hone® for Rotors is a reliable, cost-effective, automotive brush tool for do-it-yourself mechanics (DIY), professional brake specialists, and aftermarket brake rotor manufacturers. Suitable for mounting in a handheld electric drill or production equipment, the Flex-Hone® for Rotors features long-lasting abrasive globules that are permanently laminated to flexible nylon filaments.

BRM’s brake honing tools come in coarse, medium, and fine grits. Coarse-grit rotor hones remove heavy buildup and corrosion during brake jobs. Medium-grit brake tools also remove layers of pad material, but impart a smoother surface finish. Fine-grit flexible hones impart the finest rotor finish of all, and may be used after coarse-grit and then medium-grit tools.  

Named an Undercar Digest Magazine “Top Ten Tool” eight years in a row, the Flex-Hone® for Rotors was featured in the August 2014 edition DSPORT magazine. In an article called Glaze is for Donuts: Do-It-Yourself Disc Brake Resurfacing, automotive writer Jun Chen explained why BRM’s brake rotor hones are the right choice for disc brake rotor resurfacing.

From the Race Track to the AAPEX Show

First, DSPORT removed four used rotors from a race car. Equipped with a power drill and a coarse-grit flexible honing tool, a mechanic then removed the transfer layer from each rotor face. The brake tech then switched to a medium-grit tool, and finally to a fine-grit Flex-Hone® for Rotors. Because the BRM brake hone is self-leveling and applies uniform pressure, keeping it square and flat was an easy task.

As the Flex-Hone® for Rotors brochure explains, BRM’s rotor honing tool should be held securely in a collet, chuck, or similar holding device. Use light, uniform pressure rather than excessive dwell time. To produce the desired surface finish, use the brushing tool for approximately 10 - 15 seconds clockwise and 5 – 10 seconds counterclockwise. Do not overhead by dwelling for longer periods of time.

Do your tradeshow plans include a visit to the Automotive Aftermarket Products Expo (AAPEX) next month? Then visit BRM in Booth #1152 at the Sands Expo in Las Vegas and see the Flex-Hone® for Rotors for yourself. Contact BRM to arrange a meeting in advance, and learn more about Brush Research Manufacturing’s full line of automotive surface finishing solutions, as shown in this AAPEX video.