The parking brake in your vehicle is often referred to as the hand brake, e-brake, or emergency brake. However, because most modern braking systems have failsafe measures and warning systems, such as on-dash brake warning lights and low fluid level sensors, the parking brake is rarely used as an emergency brake.
The parking brake is a secondary braking system, not powered by hydraulics, and is independent of the primary hydraulic brakes used to slow and stop your vehicle. The most common use of the parking brake is to keep the vehicle motionless when it is parked. Those who drive manual transmission vehicles usually engage the parking brake every time they exit the vehicle. If not engaged, the vehicle may just roll away all on its own.
Automatic transmission drivers tend to use the parking brake far less, if at all. It is recommended that you engage the parking brake any time the vehicle is parked on a hill, whether you drive an automatic or standard transmission. Using the parking brake to stop a moving vehicle outside of a total brake failure is not recommended, but in the event of a total primary braking system failure, the parking brake can assist in stopping the vehicle, possibly preventing an accident and saving your life.
A parking brake system uses levers and cables, and bypasses the primary hydraulic brake system. This ensures a vehicle may be completely stopped in the event of a hydraulic brake system failure. It also provides an easy mechanical means to ensure the vehicle remains stopped.
There are four types of parking brake engagement styles. These include the stick lever (which is generally found under the instrument panel on older model vehicles), the center lever or pull handle (found in between the two front seats in the center console), the pedal (found to the left of the floor pedals), and the electric or push button (found among the center console controls or on the dash).
When you engage the parking brake on your vehicle, the brake cable passes through an intermediate lever, which increases the force of your pull, and then passes through an equalizer. At the U-shaped equalizer, the cable is split into two cables. The equalizer divides the forces and sends it evenly across the two cables connected to the braking mechanisms at the rear wheels.
Vehicles use either drum or disc brakes. Disc brakes on all four wheels are the most common brake configuration. In a rear drum brake application (rare on modern vehicles) the emergency brake cables run directly to the rear brake shoes, bypassing the hydraulic brake system. Vehicles with rear disc brakes have a more complicated parking brake system (sometimes requiring an entire drum brake system mounted inside the rear brake rotors) called an exclusive parking brake or auxiliary drum brake.
When the vehicle has rear disc brakes without an auxiliary drum brake, a caliper actuated parking brake system is used. With this system, an additional lever and corkscrew are added to the existing caliper piston. When the parking brake is applied, the lever forces the corkscrew against the caliper piston and applies the brake, again bypassing the primary hydraulic braking system.
Some vehicles have electric parking brakes. Instead of having a pedal, stick, or center console lever, a small button on the dash signals an electric motor to pull the brake cable. Advanced electric parking brake systems utilize computer-controlled motors to engage the brake caliper.
Even though parking brake cables are housed in protective sleeves, the cables can become corroded and rusted with infrequent use. This can result in cable failure just when you need your parking brakes the most. This is a good reason to use your parking brake often whether you have a manual or automatic transmission. Normal use prevents buildup and keeps the cables in good working condition.
Parking brakes can be dangerous if not used properly. It is easy to forget that the parking brake is on if you don’t use it often. To avoid driving with the parking brake engaged, set the parking brake as hard as you can. The vehicle will be more difficult to move, thus helping the driver sense the parking brake is set. In cold temperatures, the parking brake cables can become frozen and fail to release when disengaged. Parking in a garage or other protected area can help avoid this problem. Do not attempt to drive the vehicle if the parking brake freezes or fails to release.
Your parking brake is safe to use if your primary hydraulic brakes fail, but do not pull up on the handle or push down on the pedal quickly. This will cause the vehicle to fishtail, lock-up, and possibly skid out of control. If you are ever in the unlikely situation of hydraulic brake failure, try to stay calm and engage the parking brake slow and steady which will bring the vehicle to a longer but more controlled stop.
At least annually, have an ASE certified technician inspect the operation of your parking brake to make sure the cables are secure and routed correctly, the engagement mechanism (handle, lever, pedal, or push button) engages and releases correctly, the parking brake light on the dash comes on and goes off when the parking brake is engaged and disengaged, the cables move easily within their protective housing, and the parking brake is properly adjusted to hold the vehicle at a complete stop when the vehicle is in gear.
With regular inspection and maintenance, you can rest assured that your parking brake is in good working order in case you must rely on it for any reason. Remember: Take good care of your vehicle and it will take care of you.