Main points
- When the parking brake lever is pulled or engaged, the cable or hydraulic line exerts force on the brake shoes or pads, causing them to press against the brake drums or rotors on the rear wheels.
- The parking brake can be used to hold the vehicle in place on a hill while the driver engages the accelerator.
- Can I use the parking brake to hold the vehicle on a hill.
Parking brakes, also known as handbrakes or emergency brakes, are an essential component of any vehicle. They provide an additional layer of safety by preventing the vehicle from rolling when parked. However, a common misconception is that the parking brake locks all four wheels. In this blog post, we will delve into the mechanics of parking brakes and explore whether they indeed lock all four wheels.
How Does a Parking Brake Work?
Parking brakes typically utilize a cable or hydraulic system to engage the rear wheels. When the parking brake lever is pulled or engaged, the cable or hydraulic line exerts force on the brake shoes or pads, causing them to press against the brake drums or rotors on the rear wheels. This creates friction, which slows down or stops the vehicle from rolling.
Does the Parking Brake Lock All Four Wheels?
The answer is no, the parking brake does not typically lock all four wheels. Most vehicles are equipped with a rear-wheel-only parking brake system, meaning that only the rear wheels are engaged when the parking brake is applied. This is because the rear wheels are less likely to lock up and skid than the front wheels, especially on slippery surfaces.
Why Not All Four Wheels?
There are several reasons why parking brakes are not designed to lock all four wheels:
- Reduced Braking Power: Engaging the parking brake on all four wheels would significantly reduce the vehicle’s overall braking power. This is because the front wheels are responsible for up to 70% of the braking force.
- Increased Risk of Skidding: Locking all four wheels can increase the risk of skidding, especially on slippery surfaces. This is because the tires lose their grip on the road, making it difficult to control the vehicle.
- Potential Damage: Engaging the parking brake on all four wheels can put additional stress on the brake components, potentially leading to damage.
Exceptions
While most vehicles have a rear-wheel-only parking brake system, there are a few exceptions:
- All-Wheel-Drive Vehicles: Some all-wheel-drive vehicles may have a parking brake system that engages all four wheels. This provides additional traction and stability on slippery surfaces.
- Older Vehicles: Some older vehicles may have a parking brake system that engages all four wheels. However, these systems are less common in modern vehicles.
Other Functions of the Parking Brake
In addition to preventing the vehicle from rolling, the parking brake can also be used for:
- Emergency Braking: The parking brake can be used as an emergency brake if the primary brake system fails.
- Hill Starts: The parking brake can be used to hold the vehicle in place on a hill while the driver engages the accelerator.
- Adjusting Rear Brakes: The parking brake can be used to adjust the tension on the rear brake shoes or pads.
Key Points: Unlocking the Truth
Contrary to popular belief, the parking brake in most vehicles does not lock all four wheels. It typically engages only the rear wheels to provide additional safety and prevent the vehicle from rolling. All-wheel-drive vehicles and some older vehicles may have a parking brake system that engages all four wheels, but this is not the norm. Understanding the function and limitations of the parking brake is crucial for safe and responsible driving.
Questions We Hear a Lot
Q: Why is the parking brake not designed to lock all four wheels?
A: To reduce braking power, minimize the risk of skidding, and prevent potential damage to brake components.
Q: Can I use the parking brake as an emergency brake?
A: Yes, but it should only be used in an emergency as it is less effective than the primary brake system.
Q: How can I adjust the parking brake tension?
A: Consult your vehicle’s owner’s manual for specific instructions on how to adjust the parking brake tension.
Q: Is it safe to engage the parking brake while driving?
A: No, it is not safe to engage the parking brake while driving as it can cause the rear wheels to lock up and skid.
Q: Can I use the parking brake to hold the vehicle on a hill?
A: Yes, the parking brake can be used to hold the vehicle on a hill while the driver engages the accelerator.