System Component Description
The park brake system consists of the following:
Park Brake Lever Assembly: Receives and transfers park brake system apply input force from
driver to park brake cable system.
Releases applied park brake system when lever is returned to at-rest
(lowered) position.
Park Brake Cables: Transfers input force received from park brake lever, through park
brake cable equalizer, to park brake apply lever.
Park Brake Cable Equalizer: Evenly distributes input force to both the left and right park
brake units.
Threaded park brake cable equalizers are also used to remove slack in
park brake cables.
Park Brake Apply Lever: Multiplies and transfers input force to park brake actuator.
Park Brake Actuator: Uses multiplied input force from apply lever to expand park brake
shoe toward the friction surface of the drum-in-hat portion of the rear brake
rotor.
Threaded park brake actuators are also used to control clearance between
the park brake shoe and the friction surface of the drum-in-hat portion of
the rear brake rotor.
Park Brake Shoe: Applies mechanical output force from park brake actuator to friction
surface of the drum-in-hat portion of the rear brake rotor.
System Operation
Park brake apply input force is received by the park brake lever assembly
being depressed, transferred and evenly distributed, through the park brake
cables and the park brake cable equalizer, to the left and right park brake
apply levers. The park brake apply levers multiply and transfer the apply
input force to the park brake actuators which expand the park brake shoe
toward the friction surface of the drum-in-hat portion of the rear brake
rotor in order to prevent the rotation of the rear tire and wheel assemblies.
The park brake lever assembly releases an applied park brake system when it
is returned to the at-rest (lowered) position.