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What Causes a Parking Brake to Fail?

CarPart  ·  March 17, 2023

What Causes a Parking Brake to Fail?

The parking brake in your car is separate from the driving brakes. While driving brakes are connected to the brake pedal and use hydraulics to function, the parking brake is engaged by a cable connected to the brake lever. So, what causes a parking brake to fail?

A parking brake malfunction could happen due to a faulty lever – it could also be caused by a problematic pedal, handle, button, or a rusty cable. Besides those, parking brakes can also seize due to excessive heat or cold, and in some cases, the problem can come from a faulty sensor.

The parking brake doubles as the emergency brake, so you don’t want to leave this problem unresolved. Read through this guide to understand the root causes of parking brake failure and whether you should drive if your car has this issue.

What Causes Parking Brake Failure?

The common reasons for parking brake failure – whether your car uses disc or drum brakes for its parking brake – are:

1. Faulty Lever, Pedal, Handle, or Button

There are several components in your car's parking brake system. The part you can touch and control is inside the vehicle cabin, and you use it to engage or disengage the parking brake.

Most people have learned how to disengage a parking brake by using a lever. However, cars these days have various mechanisms to fulfil the same purpose, including levers, handles, or even a separate pedal.

Meanwhile, many newer car models use a button to engage their electronic parking brake system. Regardless of the type of mechanism your car uses, it is the parking brake's first point of failure. 

When the brake pedal, lever, handle, or button is faulty, you’ll have problems engaging or disengaging the parking brake. Unfortunately, that’s true even if all other components in the system are in excellent working condition.

2. Corroded Cable

The parking brake system is unique because it works separately from your driving brakes. While pressing the pedal activates the driving brake, it’s the parking brake cable that engages or disengages the parking brake.

Simply put, the system tightens the cable when you engage the parking brake and loosens it when you disengage the parking brake to resume driving.

Unfortunately, that cable can become corroded over time, causing either or both of two things.

Firstly, the parking brake cable can become corroded or rusty if the vehicle is really old or left unused and uncared for. That’s just a part of its natural wear and tear like what happens to all other metal parts in your car.

If you’ve left the car parked and unused for some time, don’t be surprised to find rust on everything metal, including the brake cable. That’s because the cable doesn’t go through the normal process of tightening and loosening that happens with everyday use.

3. Seized Brake

Even if the parking brake mechanism is functioning and the cable is in excellent condition, failure can occur if the brake components themselves have seized.

In other words, you can pull the parking brake lever and the cable will tighten or loosen, yet the brake components remain frozen.

There are three causes of a seized parking brake:

Seized parking brakes are problematic whether you’re trying to engage or disengage them.

4. Faulty Sensor

Did you notice your parking brake indicator lighting up for no apparent reason? It could be a case of a faulty sensor.

Remember, your car has different sensors installed throughout the vehicle. That’s especially true if your car was produced in the past few years, as vehicles have become heavily reliant on such sensors.

In this case, we're talking about the sensor for your parking brake. However, when the sensor is not functioning correctly, you can only imagine the dangers it can bring. Any erroneous data it feeds to the onboard computer can cause problems with the overall parking brake mechanism.

5. Brake Component Issues

Last but certainly not least, your parking brake could fail due to a mechanical problem in its components. In other words, the failure has nothing to do with sensors, cables, or levers but instead with one of the components at the brake itself.

For instance, your drum brake might have a broken parking brake adjuster, or a disc brake might have a problem with its piston.

Whatever the case, such issues will cause a lack of braking power even when you engage the parking brake.

Can You Drive with a Parking Brake Fault?

Your car will still run despite a parking brake problem, if that’s what you’re asking. However, we don’t advise driving a car with a compromised parking brake system.

Any time your car’s braking system has a problem, whether it’s with the driving or parking brakes, the vehicle becomes unsafe to drive. Not only does it endanger you and your passengers, but it also puts other road users at risk.

Your best and safest option is to tow the car to your preferred mechanic, who can repair the emergency brake cable or whatever component is affected.

You can find the nearest workshop in your area using the CarpartAU Directory. You can narrow down all the automotive service providers closest to you and get their contact details. 

Did you find this post helpful? Don’t hesitate to share it with friends and family. Keep safe always!


By Ray Hasbollah

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