Hand brake system or Parking Brake

The parking brake system, also known as the hand brake or emergency brake, is a vehicle component used to keep a car stationary when parked. It is independent of the main braking system, designed to secure the vehicle and act as a backup in emergencies. 

1. Primary Functions of the Parking Brake System

• Hold the Vehicle in Place: Prevents the vehicle from rolling on slopes or inclines when parked.

• Emergency Use: Provides limited braking if the primary hydraulic brakes fail.

2. Types of Parking Brake Systems

• Mechanical (Manual) Parking Brake: Uses a lever and cable system that applies tension to the rear brakes.

• Electronic Parking Brake (EPB): Uses an electronic control unit (ECU) and motorized actuators to apply the rear brakes at the push of a button.

3. Key Components

• Lever or Pedal (Mechanical Systems): A lever between the front seats or a foot pedal on the left side of the driver’s footwell.

• Button (Electronic Systems): Found on the dashboard or center console, used to activate the EPB.

• Cables (Mechanical): Steel cables connect the lever/pedal to the rear brakes to apply tension and engage the brakes.

• Electronic Actuator (EPB): Motors or actuators apply force to the rear brakes electronically.

• Brake Shoes or Calipers: Engage with the rear drum or disc brakes to create friction and hold the wheels stationary.

4. How Each System Works

• Mechanical Parking Brake: When the lever is pulled or pedal pressed, it tightens the cables, which apply force to the brake shoes (in drum brakes) or calipers (in disc brakes) on the rear wheels. This friction prevents the wheels from rotating, keeping the car in place.

• Electronic Parking Brake: The driver activates the EPB with a button, sending a signal to an ECU that controls motors or actuators on the rear brakes. The motors apply the brake pads or shoes to the rotors or drums, securing the vehicle. Many EPBs automatically engage in “Park” mode and disengage when the car accelerates.

5. Automatic Features in Modern Systems

• Auto-Hold Function: Keeps the brake engaged when the car is stopped in traffic, releasing only when the driver accelerates.

• Automatic Engagement and Disengagement: Many electronic parking brakes automatically engage when the car is in “Park” or disengage upon acceleration.

6. Advantages of Each Type

• Mechanical System: Simple, reliable, and easy to repair but requires regular maintenance for cable tension.

• Electronic System: Adds convenience and safety features but is complex and can be costly to repair if the actuator or ECU malfunctions.

7. Common Issues

• Stuck or Seized Parking Brake: Often due to corrosion or lack of use, especially in mechanical systems.

• Cable Wear and Stretching: In mechanical brakes, cables can stretch and may need adjustment over time.

• Electronic Malfunctions: In EPB systems, actuator or ECU failures can prevent the brake from engaging or disengaging.

8.When to Use the Parking Brake

• Parking on Inclines: Essential to prevent the vehicle from rolling.

• Everyday Use: Using the parking brake every time you park helps maintain the system in good condition.

• As an Emergency Brake: Though not very effective, it can be used to slow the vehicle if the main brakes fail.