To prevent unnecessary wear and tear on your transmission, and to ensure that it doesn’t slip out of park and roll when you’re parked on an incline, your vehicle is equipped with a parking brake.
Engaging the parking brake activates the rear brakes, and ensures that the car won’t roll, even on a relatively steep incline. However, if your parking brake won’t hold the car, there’s a problem that must be addressed for your safety (and that of others).
How this system works:
Parking brake systems vary drastically from one automaker to another, and even on different makes and models. Some have a supplemental set of shoes inside a built-in drum on the rear rotors (disc brakes). Some use the rear shoes of the primary drum system as the parking brake. However, all of them should be able to hold the car on an incline.
When you activate the parking brake, either by pulling up the handle between the front seats or pushing the parking brake pedal under the dash, a cable that runs to the rear of the vehicle is pulled taut. This engages the parking brake. When you disengage the pedal or lower the handle, release springs in the rear return the brake system to its normal configuration and you’re able to drive.
Over time and through (lack of) normal use, your parking brake system might shift out of adjustment.
Common reasons for this to happen:
Brakes Out of Adjustment: The most common reason for a parking brake not to hold a car on an incline is that the brakes are out of adjustment. Most parking brakes are self-adjusting, which means that they automatically adjust through use. However, if you don’t use your parking brake very often, the system is thrown off (it’s not able to self-adjust if it’s not used).
Adjuster Wheel Damaged or Seized: Manually adjusting your brake pads is done with an adjuster wheel, which changes the spread of the shoes inside the drum. However, if the wheel is damaged or seized, you will not be able to adjust the shoes.
Drum Damage/Wear: If it has been some time since you had your drums resurfaced, the wear on the inside may make it impossible for the shoes to make contact with the surface (or make only light contact, meaning that while the brake engages, it won’t be enough to hold the car).
Brake Not Engaging: It might not be a question of the parking brake not holding the car. It might be a question of the parking brake not engaging at all. Rust, corrosion, damaged return springs and numerous other problems can prevent your parking brake from engaging in the first place.
What to expect:
A top-rated mobile mechanic will come to your home or office to inspect the parking brake, including the adjustment of the rear brakes, the condition of the cable and other components. The mechanic will then provide a detailed inspection report that includes the scope and cost of the necessary repairs.
How it's done:
The mechanic will need to inspect the entire parking brake system, including the handle, the cable, return springs, shoes and more. It’s likely that the mechanic will have to remove both rear wheels, as well as the drums in order to inspect the shoes and adjust the brakes if necessary.
How important is this service?
If your parking brake won’t hold the car, then parking on even a slight incline can be very dangerous. Even an automatic transmission can slip out of park, and if you’re driving a stick shift, it can also slip out of gear. When this happens, the car will roll down the incline, impacting anything in its way. One of our professional mechanics can inspect and repair your parking brake to ensure safety at all times.