How Parking Brakes Work

Summary

This video provides a detailed explanation of how the parking brake system works in a car. It covers the mechanical activation process, including the e-brake cable running through the vehicle to the rear wheels. The video demonstrates the different types of parking brake actuators (foot and hand brake), the components of the brake system, and how the parking brake engages the rear wheels to prevent rolling. The process of disassembling the parking brake components, including the drum, shoes, adjuster, and return springs, is also shown, explaining how each part contributes to the overall function of the system.

Takeaways

• 😀 The parking brake works mechanically through a cable system that engages the rear wheels of the car.
• 😀 The cable runs from the parking brake handle or foot brake actuator, down to the rear wheels through the transmission tunnel.
• 😀 The parking brake system splits the cable at a connector, distributing it to both rear wheels, preventing rolling when parked on an incline.
• 😀 Two types of parking brake actuators exist: the foot brake and the hand brake, with similar components but different actuation methods.
• 😀 The parking brake assembly is attached to the firewall with four 12-millimeter nuts and features an adjustment nut for fine-tuning.
• 😀 The parking brake works as a drum brake, housed in the rotor, and prevents wheel movement when engaged.
• 😀 The parking brake shoes feature friction material that wears down, requiring replacement when it reaches about one millimeter in thickness.
• 😀 An adjuster mechanism is used to maintain the proper position of the shoes relative to the drum, ensuring the parking brake engages properly.
• 😀 The foot brake system uses a ratcheting mechanism to engage, lock, and disengage the parking brake, with an indicator switch for dashboard lights.
• 😀 The parking brake handle or foot lever uses a cable that engages the brake through tension adjustment via an adjustment nut.
• 😀 A return spring ensures that all components of the parking brake assembly stay in place and function properly without falling apart.

Q & A

How does the parking brake differ from conventional brakes?

Unlike conventional brakes, which are hydraulically activated, the parking brake is mechanically activated through a cable that runs to the rear wheels of the vehicle.

What happens when the parking brake is engaged while the vehicle is rolling forward?

When the parking brake is engaged while the vehicle is rolling forward, the rear wheels are locked, preventing the vehicle from rolling.

What are the two types of actuators for the parking brake system?

The two types of actuators are the foot brake and the hand brake. Both types use separate lines that join at a T-connector before reaching the rear wheels.

How does the parking brake cable work within the vehicle?

The parking brake cable travels from the center console and runs underneath the transmission tunnel, eventually reaching a splitter that sends the signal to each rear wheel.

What is the role of the parking brake assembly in the rear wheels?

The parking brake assembly, housed within a drum on the rotor, constrains the rear wheels from turning when engaged, effectively locking the vehicle in place.

What components are involved in the parking brake shoes mechanism?

The parking brake shoes are connected to a retainer, adjuster, return spring, and two retaining pins. When the parking brake is applied, these components push the shoes against the drum, locking the rear wheels.

How do the parking brake shoes engage with the drum?

When the parking brake is engaged, the parking brake cable pulls on the shoes via a retainer mechanism, causing the shoes to expand outward and make contact with the drum to prevent wheel movement.

Why is it important to lubricate the contact points of the parking brake assembly?

Lubricating the six contact points of the parking brake assembly ensures smooth operation, preventing wear and tear, and extending the life of the components.

What role does the adjuster play in the parking brake system?

The adjuster allows the static position of the parking brake shoes to be set in relation to the drum's inner diameter. It ensures that the parking brake engages firmly by providing proper tension when the drum is installed.

What is the function of the foot brake actuator in the parking brake system?

The foot brake actuator uses a cable to engage the parking brake when the driver steps on the brake pedal. The actuator also has an adjustment nut to control the pedal's travel before the parking brake engages.

How does the ratcheting mechanism in the parking brake actuator work?

The ratcheting mechanism in the parking brake actuator locks the brake in place when engaged. It uses spring pressure to hold a tooth against the lever's teeth. To release the brake, the lever is slightly moved, which disengages the lock.