User's Manual

96
BW7248
GLOSSARY OF TERMS
Cam Base Circle Radius: The perpendicular distance from the center of the s-cam to the vector defi ned by the
center of the cam roller and the intersection of the cam roller with the s-cam profi le. Most CBCR are designed to
be at or near 1/2 inch.
Clevis pin: Pin connecting the arm of slack adjuster to a brake chamber push rod yoke.
CMVSS: Canadian Motor Vehicle Safety Standard
Coeffi cient of Friction: Developed by Friction Materials Standards Institute, a double-letter code printed on the
edge of a brake block to designate its range of aggressiveness. (Example: EE, FF, GG, FG)
Cracked Drum: Brake drum cracked all the way through by excessive heat build-up (perhaps signifying
inadequate drum weight and/or driver abuse) and/or resurfacing of a drum beyond the manufacturer’s limit.
CTI: Central tire infl ation
Dual Brake System: Mandated by FMVSS 121, the use of a dual air system (primary and secondary) in order
to retain braking ability in the event one system fails.
Dust Shield: A plate made of metal or polyethylene that is mounted behind a brake drum to minimize the entry
of dirt and road splash.
EBS: Electronic braking system
ECU: Electronic control unit
Edge Code: The information found the edge of a brake block. Bendix friction edge coding includes the type of
friction and the coeffi cient of friction.
Emergency Brake System: Not a separate system, emergency braking (in event of air loss) involves various
portions of the parking and service brake systems.
Engine Brake: An optional device that converts a diesel engine into a power-absorbing air compressor to slow
a vehicle on downgrades.
ES: Extended Service, Bendix’ term for brake design using thicker than standard lining.
ESII: Bendix’ redesigned Extended Service brake shoe, introduced in 1996. It employs a new Hot Staked
manufacturing process, redesigned retaining springs, lighter weight and elimination of the tabs from the
previous design table.
Exhaust Brake: An optional device that uses engine exhaust back pressure to slow a vehicle on downgrades.
FC: Fast Change, Bendix’ term for brake design with an open anchor pin rib. Interchanges with Rockwell Q
design.
FCII: Bendix’ redesigned 12-1/4 Fast Change brake shoe, introduced in 1996. It includes a redesigned table,
thicker rib material, an improved welding process, and standardization of brake hardware components.
FMSI: Friction Materials Standards Institute
FMVSS: Federal Motor Vehicle Safety Standard
Foundation Brake System: A term inclusive of mechanical components involved in mechanically providing
braking force: brake chambers, slack adjusters, brake drums, brake shoe assemblies.