Troubleshooting guide

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For more information, visit www.bendix.com or www.foundationbrakes.com • 1-800-AIR-BRAKE (1-800-247-2725)
The Control System: Air Disc Brakes
Lever
Rotor
Eccentric
Bearing
Inner Brake
Pad
Outer
Brake Pad
Actuating
Beam
Actuator
Rod
Supply Port
tappets, which force the inner brake pad into contact with
the brake rotor. Further movement of the actuating beam
forces the caliper — sliding on two stationary guide pins
— away from the rotor, which pulls the outer brake pad
into the rotor. The clamping action of the brake pads on
the rotor applies braking force to the wheel.
Releasing the foot brake releases pressure in the
service brake chamber. With no pressure in the service
brake chamber, return springs force the air disc brakes
into a neutral, non-braked position. The non-braked
position is mechanically controlled by a brake adjuster
mechanism in the caliper. The caliper contains a brake
adjuster mechanism that turns threaded tubes to set
a gap (running clearance) between the rotor and the
brake pads. When operated manually with the adjuster
shaft, the adjuster mechanism sets the system’s non-
braked position. The adjuster mechanism also operates
automatically, whenever the brakes are activated, to
compensate for rotor and brake pad wear and to keep
the running clearance constant.
The rotor-friction couple is carefully designed for optimal
performance and durability. It is recommended that only
approved replacement disc pads or rotors be used to
prevent damage to disc brake components (e.g. cracked
rotors) or premature or uneven pad wear, which can
adversely affect braking performance.
Bendix air disc brakes are a “fl oating caliper” design for
use as a foundation brake on all axles of heavy commercial
vehicles and trailers. In terms of performance and ease
of service, Bendix
®
air disc brakes compare favorably to
traditional foundation drum brakes. They are available
in models with or without a combination spring brake
chamber.
Bendix air disc brakes convert air pressure into braking
force. When the foot brake is applied, air from the vehicle
brake system enters the service brake chamber through
the supply port, applying pressure to the diaphragm. The
pressure pushes the diaphragm, moving the pressure
plate and push rod against a cup in the lever. The lever
pivots on an eccentric bearing and transfers motion to
the actuating beam. Moving against return spring force,
the actuating beam moves two threaded tubes and
Air Disc Brakes
Brake
Chamber
Brake Pad
Friction
Material
Rotor
Bendix
®
Air Disc Brake
Air Disc Brake
Cut-away View