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Park Brake System Description and Operation

Park Brake System Description and Operation

System Component Description

The park brake system consists of the following:

Electronic Parking Brake (EPB) Control Module Assembly

Transfers park brake system apply input force to the park brake cable system.

Electronic Parking Brake Switch

Applied by the driver and activates EPB control module or Electronic Stability Control (ESC) braking system.

Parking Brake Cable

Transfers input force received from the electronic parking brake control module, through the parking brake cable equalizer, to the parking brake apply lever.

Parking Brake Cable Equalizer

Evenly distributes input force to both the left and right parking brake assemblies.

Parking Brake Apply Lever

Multiplies and transfers input force from the parking brake cable to the parking brake actuator.

Parking Brake Actuator

Uses multiplied input force from the apply lever to expand the parking brake shoes toward the friction surface of the drum-in-hat portion of the rear brake rotor.

Parking Brake Adjuster

Threaded parking brake adjusters are also used to control clearance between the parking brake shoes and the friction surface of the drum-in-hat portion of the rear brake rotor.

Parking Brake Shoe

Applies mechanical output force from the parking brake actuators to the friction surface of the drum-in-hat portion of the rear brake rotor.

System Operation

Park brake apply input force is received by activating the electronic parking brake switch signaling the EPB control module, and transfers an evenly distributed force through the parking brake cables and equalizer to the parking brake apply levers. The parking brake apply levers multiply and transfer the input force to the parking brake actuators which expand the parking brake shoes toward the friction surface of the drum-in-hat portion of the rear brake rotors to prevent the rotation of the rear tire and wheel assemblies. The electronic parking brake switch is activated signals the EPB module to release applied input force to the parking brake cables. The EPB module then removes the applied input force and releases the parking brake.