Your car has two braking systems – one is activated when you press the brake pedal. The other is activated when you engage the parking brake by either pulling up the lever beside the driver seat or pressing the parking brake pedal (depending on your make and model).
The parking brake is mechanical, rather than hydraulic. It works based on a series of steel cables that attach to the lever or pedal in the front of the car, and run back to the rear brakes. If you have rear drum brakes, activating the parking brake actually pushes the shoes of your regular brakes against the inside of the drum. If you have disc brakes in the rear, then your parking brake has its own drum, built into the disc brake system (in some cases – other automakers use a system that closes the caliper against the rear rotor, so there is no parking brake drum).
Unlike your normal braking system, the parking brake shoes are only used when the parking brake is engaged. So, if you press the brake pedal, the parking brake system is not in use. It’s only activated when you pull the lever or press the parking brake pedal down.
In general, your parking brake drum and shoes should last for a very long time, up to the life of the vehicle. However, there are things that can seriously reduce that lifespan. The most common is putting the car in gear and driving with the parking brake still engaged. This puts immense wear on both the shoe and the parking brake drum, and can cause premature failure.
You’ll also create significant wear to the parking brake drum if you engage the brake while you’re driving (using the parking brake as an emergency brake to augment the primary braking system).
A worn parking brake drum won’t keep you from driving your car, but it can lead to safety problems, particularly when parking on a slope (there’s a chance that your car will roll). If you encounter any problems, have a professional mechanic inspect and replace the parking brake drum in your vehicle.
Watch for these symptoms to indicate that your parking brake drum or the entire parking brake system needs repairs:
- Car rolls when the parking brake is engaged
- Too much travel in the parking brake lever or pedal (also an indicator of cable wear)
- The brake will not hold the car in place when you idle the engine in gear
This article originally appeared on YourMechanic.com as How Long Does a Parking Brake Drum Last? and was authored by Valerie Johnston.