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What is a car’s parking brake and how does it work?

How does a car's handbrake work?

How does a parking brake work?

A car's parking brake, also known as a handbrake, usually takes the form of a hand-operated lever and is normally located on the centre console but can sometimes be found between the driver’s seat and the door.

The handbrake applies the rear disc pads or brake shoes via a cable and is used when the car is parked to stop it rolling forwards or backwards.

To apply it, you hold the hand grip, press the button (usually at the end of the grip) and raise the lever. Some modern cars have replaced the manual lever with an electric handbrake.

As you raise the manual lever you’ll feel resistance as the brakes are applied. When you feel the brakes are exerting sufficient force to hold the car you release the button and a pawl engages on a ratchet plate, holding the lever (and the brakes) in place.

To release the brakes you raise the lever slightly to disengage the pawl tooth from the ratchet, press the button and lower the lever.

Handbrake being applied in a car

What goes wrong with a parking brake?

Some drivers don’t press the button when raising the handbrake. It still operates as normal, but over time the ratchet teeth will wear and eventually they'll cause the handbrake - and the rear brakes - to fail, so it’s good practice to use the hand brake button when you’re raising the lever.

Sometimes, on cars such as older Mercedes, the hand brake takes the form of a foot brake down in the footwell, to the left of clutch on a car with a manual gearbox or the brake pedal on an automatic car. You press the pedal with your foot to apply the brake and release it via a handle on the dashboard.

Is your car's handbrake lever pulling up too high before the brakes engage? The cable may have stretched or the rear brakes may be worn.

The cable can be adjusted via a nut behind the handbrake assembly and the rear brake pads or shoes can be changed – every Haynes Manual includes step-by-step instructions.

Car electronic handbrake

Manual handbrake vs electronic handbrake

Instead of the hand brake lever and cables that run from it to both rear brakes, an electronic handbrake, also known as an electric parking brake, uses a switch – usually between the front seats – that is connected via electrical wiring to motors on the rear brakes that actuate the pads.

How an electronic handbrake works differs slightly, depending on the car manufacturer. Typically, the electronic handbrake can be set to automatically activate when you come to halt, say at a junction.

When you lift the clutch pedal in a manual car or press on the accelerator in a car with an automatic gearbox, the rear brakes automatically release.

An electronic handbrake also often adds a 'hill hold' or auto hold function, which makes hill starts a lot easier compared to a conventional handbrake – the hill hold function temporarily applies the brakes (usually for a couple of seconds) while you let out the clutch and engage the gearbox.

The brakes then release and off you go, with no drama. Useful if your hand-foot coordination isn't the best!