There’s nothing worse than a stuck parking brake. This inconvenient issue impacts more vehicles than you may think, and leaves you stranded when your emergency brake won’t disengage.
But don’t worry. Stuck brakes have causes. Understand what causes parking brakes to freeze up and how to manually release one in case you are ever in that situation.
What is a Parking Brake?
A parking brake is an auxiliary braking mechanism designed to stop a vehicle from rolling forward or backward movement of a vehicle, even when traditional hydraulic brakes are not applied.
In almost every case, a parking brake, or e-brake, works using nothing more than mechanical force. This means that it does not require hydraulic or electrical input to engage.
Parking brakes are typically actuated via cable and require either the driver to depress a specialty pedal or the driver to pull a handbrake lever, depending on the implementation.
A parking brake will pull the parking brake cable and apply tension on a tensioning device.
The pressure is released by either the driver disengaging the parking brake pedal or by dropping the handbrake lever back into a neutral position.
If the driver forgets to disengage the parking brake before driving away, the emergency brakes can drag, which can have some unfortunate consequences.
Types of Parking Brakes
There are many different types of parking brakes currently in service along today’s roadways. The type of parking brake equipped on a vehicle will depend on the manufacturer including the model.
The following outlines the most common types of parking brakes in use today.
Drum-Style Parking Brake
These systems utilize a cable-driven lever to engage the assembly’s brake shoes to wedge themselves against the brake drum’s inner diameter.
There is no direct actuation of the wheel cylinder, as is common with a standard hydraulic brake application.
Disc/Drum Hybrid Parking Brake
Many 4-wheel disc brake-equipped vehicles currently use a drum-style parking brake assembly, mounted within the hat of a rear brake rotor, which is also actuated using a cable-driven assembly.
When the parking brake cable is tensioned, the internally mounted brake shoes interface with the interior face of the rotor hat, engaging friction.
Modified Disc Parking Brake
Many newer vehicles that are equipped with 4-wheel disc brakes now include a modified disc brake parking brake, which uses the rear calipers for actuation.
This version uses a cable-driven lever to force a caliper’s brake piston outward, which is the opposite of a service brake application, which is done by means of hydraulic force.
Electronic Parking Brake
Many vehicles have begun to use electronically actuated parking brakes. This system is contained and controlled via the vehicle’s rear brake calipers.
The operation relies on an electric motor, which, upon activating a switch or button, causes the electric motor to extend a brake caliper’s piston to cause brake pads to interface with their rotor.
Reasons why your Parking Brake Stuck
There are many reasons why a parking brake can stick on a vehicle, and each of the reasons can be equally concerning. Here are some of the most common in the driving region:
#1. Corrosion.
Corrosion is probably the most common reason for a stuck parking brake. Over time, the cable, mechanism, or linkage that makes a parking brake function can rust and render it inoperative.
That’s the case most often for those vehicles that have been driven primarily in the north, where salt is liberally sprayed to keep the roads clear of ice. It doesn’t matter if a vehicle is exposed to road salt in winter; other elements of salt roads can add to corrosion issues if a vehicle’s parking brake is not often used.
#2. Freezing Weather.
When extremely cold weather sets in, many things can cause problems related to brakes. In northern climates, the emergency or parking brake is most likely to actually freeze in the applied position if the car is parked overnight or for an extended period of time.
A handbrake mounted on the rear of a car, particularly parked in chilly, wet weather, if the parking brake was set very recently. The driver will then have to use their best judgment to thaw out their frozen brake linkage.
#3. Excessive Application.
Most drivers don’t know that they can jam their parking brake. Excessive force set either by a hand lever or a foot pedal can jam it.
It only takes a slight press of force to set a safe parking brake. Any more, can prolonging applications make the vehicle’s parking brake cable stretch or bind the parking brake’s terminal linkage?
#4. Sticking Brake Caliper.
The parking brake system of a vehicle takes the rear brakes, and uses a mechanism engaged to hold the brakes on, and disengaged to hold the brakes off. If the brake caliper that the parking brake operates isn’t releasing properly, it applies the parking brake to remains stuck.
This is mostly due to a frozen or seized caliper piston. The piston applies pressure to the brake pads, which also applies pressure to the rotor, which slows the car moving forward or backward.
A stuck piston can have no pressure on the brake pads, and slow to release, or has not released the brake pads from touching the rotor while in parking brake disengaged.
The car can also have an improperly performing caliper slide pin. The slide pin allows the caliper to pivot (move) and apply pressure evenly onto both brake pads.
If the caliper gets tweaked or the slide pin gets stuck or dry, that could allow the caliper to stay applied once disengaged on both pads and not release fully.
#5. Sticking Wheel Cylinder.
If the vehicle with the parked emergency brake has drum brakes, a stick emergency brake may involve the rear wheel cylinders as a possible item in the functioning properly. This is similar to the above seized brake caliper.
Instead of the caliper not releasing from the brake rotor, the drum wheel cylinder fails to release from the brake shoe at the rear of the emergency brake.
Can You Drive If Your Emergency Brake Is Stuck?
Driving with a stuck parking brake is never recommended. This is because the offending brake shoe or brake pad will continue to drag across its brake rotor or drum.
All of this continuous friction will have heat build-up within seconds. The heat may even result in fire. In many cases, the stuck parking brake is accompanied by a burning smell and even some smoke.
Furthermore, attempting to drive with a stuck parking brake risks major damage to the vehicle’s braking hardware.
In addition to that, excessive wheel-end heat build-up, like that produced by a stuck parking brake, could harm hub and axle seals and, in extreme situations, could lead to failure.
In any case, a stuck parking brake should be taken seriously and dealt with as soon as possible. If you do not feel capable of remedying the situation with your vehicle’s parking brake, you should call a tow truck and make arrangements with a qualified service to have it repaired.
Can the Parking Brake be Disengaged Manually?
In many cases, a stuck parking brake can be disengaged manually so that the vehicle can be operated.
However, doing so requires one to have an understanding of how the parking brake works and what specifically caused the parking brake to malfunction.
However, for newer cars with electronic parking brakes, manual disengaging will often not be possible by the owner, as the computer governs the system as opposed to a mechanical parking brake.
The next section will describe how to manually reset a traditional parking brake.
How to Release a Stuck Emergency Brake
When a vehicle’s parking brake has become stuck, heat needs to be introduced to get rid of any binding that may exist.
Often times just letting your vehicle idle for an extended period of time may create enough heat via exhaust to solve the problem at hand.
However, this time-consuming process could be commensurately shortened by applying some precision-focused heat using a propane torch.
If freezing is not the case, and corrosion might be the reason for your parking brake issues, just repeatedly applying hydraulic brakes with the vehicle’s engine running may resolve brake thawing, although a mechanical intervention may also be required.
In many circumstances, repeating the process of supplying a few focused spritzes of white lithium grease or penetrating oil, followed by tension on the parking brake cable, may work.
In the rarest of cases, you might have to attempt to disengage the e-brake by hand.
Typically, this would mean providing tension using your hand on the parking brake cable at or near the point where the two pieces of parking brake cable meet or where the parking brake is connected to its same lever.
You would do this by sliding spring-loaded vice grips on this cable and prying it from its retainer or hanger.
When to Call a Mechanic
Sometimes, troubleshooting and unsticking a parked brake just requires a professional, and that’s the way this works, regardless of whether you are congenitally gifted in DIY repair or not.
Once you’ve attempted warming up your car’s engine to melt the ice off or maybe gently tapping the wheel, it is time to call a tow truck.
Don’t risk forcing it or damaging your car in some other way – a safe choice is just getting towed to a mechanic close by.