Troubleshooting guide

21
For more information, visit www.bendix.com or www.foundationbrakes.com • 1-800-AIR-BRAKE (1-800-247-2725)
The Control System: Foundation Brakes
The foundation brake is the actual braking mechanism
located at each end of the axle that provides the primary
retardation for controlling vehicle speeds. It generally
consists of an air service and/or spring brake chamber,
Foundation Brakes: Drum Brakes (aka S-Cam) and Air Disc Brakes
Axle
Shoe
CAM
Automatic
Slack Adjuster
S-CAM FOUNDATION
DRUM BRAKE
Spider
Friction Material
Brake Chamber
a mechanical brake mechanism and friction material.
Two main types of foundation brakes are in use: S-Cam
foundation drum actuated brakes (traditional and newer
wide-brake versions) and Air Disc Brakes.
The Importance of High Performance Friction to Maintain Braking Performance and Safety
In August 2011, the National Highway Traffi c Safety Administration (NHTSA) mandated a 30 percent reduction
in stopping distance for new three-axle tractors with Gross Vehicle Weight Ratings (GVWRs) up to 59,600 lbs.
Reduced Stopping Distance (RSD) is meant to signifi cantly improve safety, avoid highway fatalities, and reduce the
number of rear-end collisions. Phase two of the mandate (Aug. 1, 2013), adds tractors with two axles, as well as
severe service tractors with GVWRs above 59,600 lbs.
In the new RSD era, Bendix completed stopping-distance testing and analysis of RSD compliant brakes relined with
a range of aftermarket friction products.
Bendix compared the 60 mph stopping distance of an RSD-compliant vehicle equipped with high performance brakes
and linings against several pre-RSD OE brake linings. The RSD-compliant vehicle used Bendix
®
High Performance ES
™
(Extended Service) Brakes. Bendix
®
brand High Performance Friction had a stopping distance of 215 feet, well under the
250-foot limit established by the federal mandate. None of the comparison friction used in the relining of the RSD brakes
met the stopping distance requirement. The worst-performing friction material, a popular aftermarket lining, had a stopping
distance of 311 feet, a 45 percent decrease in performance from the Bendix friction. The 96-foot difference represents
approximately fi ve passenger car lengths.
Delivering lower fade and better thermal management, High Performance (HP) Friction from Bendix performs at high
heat better than any previous OE drum brake linings, resulting in signifi cantly shorter stopping distances.
For more information about Bendix High Performance Friction, visit www.foundationbrakes.com.
Brake Pads
Rotor
Friction Material
Replacement Kit
Friction
Material
Replacement
Kit
AIR DISC BRAKE