A seized parking brake can stop you in your tracks. This troubling issue affects more vehicles than you’d think, leaving you stranded when the emergency brake won’t release.
But don’t panic. Stuck brakes have identifiable causes. Learn what makes parking brakes freeze up and how to manual disengage it in case it ever happens to you.
See Also: 3 Reasons a Car Won’t Shift Out of Park
What is a Parking Brake?
A parking brake is an auxiliary braking mechanism, capable of preventing forward or aft movement of a vehicle, even when traditional hydraulic brakes are not applied.
In almost every case, a parking brake, or e-brake as it is often called, operates purely off of the principle of mechanical force. This eliminates the need for hydraulic or electrical input.
Parking brakes are almost always cable actuated by design, and are reliant upon the depression of a specialty pedal, or the sweep of a handbrake lever, depending upon the vehicle in question. An application of this type pulls a vehicle’s parking brake cable, thereby applying pressure to a tensioning device.
Pressure is released upon this brake mechanism by disengaging a vehicle’s parking brake pedal, or by lowering a handbrake lever back to its neutral position. Failing to do so before driving away will cause a vehicle’s emergency brakes to drag, often with dire consequences.
Causes of a Stuck Parking Brake
There are numerous conditions that can cause a vehicle’s parking brake to stick, each of which can prove equally as problematic in the moment. The following are several of the most common causes of a stuck parking brake.
#1 – Corrosion
Corrosion is by far, the most common cause of a stuck parking brake. With time, a vehicle’s parking brake cable, mechanism, or linkage can fall victim to rust, thereby rendering it inoperable.
This is especially common in vehicles that have spent much of their time in northern climates, where the regular application of road salt is standard practice. These problems are only exacerbated if a vehicle’s parking brake is seldom used.
#2 – Freezing Weather
Extreme cold weather can cause many brake problems. In many northern climates, a vehicle’s parking brake can actually freeze in the applied position, if left set overnight, or for an extended period.
A handbrake frozen on a car is more likely if a vehicle has been driven in wet weather, directly before being parked with the emergency brake set. In such cases, one must find a way to thaw their frozen brake linkage, before proceeding.
#3 – Rigid Application
Believe it or not, it is actually possible to jam your parking brake, by using excessive force when setting it, either by a foot pedal or hand lever.
Only moderate force is required for a safe parking brake application. Anything in excess of this can cause a vehicle’s parking brake cable to stretch or can bind a parking brake’s terminal linkage, all of which can prove troublesome.
Read Also: 5 Causes of Brakes Locking Up While Driving
#4 – Malfunctioning Brake Caliper
The parking brake system is connected to the rear brakes of a car, and it uses a mechanism to engage and disengage the brakes. If the brake caliper is sticking or not releasing properly, it can cause the parking brake to become stuck.
A specific cause may be a frozen or seized caliper piston. The caliper piston is responsible for applying pressure to the brake pads, which in turn apply pressure to the rotor to slow or stop the car. If the piston is stuck, it may not release the brake pads fully, causing them to remain in contact with the rotor even when the parking brake is disengaged.
A malfunctioning caliper slide pin may also be to blame. The slide pin is responsible for allowing the caliper to move freely and apply pressure to the brake pads evenly. If the slide pin is not lubricated properly or is damaged, it can cause the caliper to stick and prevent the parking brake from releasing fully.
#5 – Malfunctioning Wheel Cylinder
If you have a vehicle with drum brakes, a rear wheel cylinder may cause the emergency brake to get stuck. It’s similar to a seized brake caliper above. But instead of a caliper not releasing from a brake rotor, the wheel cylinder is not releasing from the brake shoe.
Can You Drive If Your Emergency Brake is Stuck?
This constant friction will begin to cause heat build-up within seconds, even presenting the risk of fire. In many cases, a stuck parking brake will be accompanied by a burning smell and even a fair amount of smoke.
Attempting to drive with a stuck parking brake will also risk significant damage to a vehicle’s brake hardware. In addition to this, excessive wheel-end heat build-up, such as that generated by a stuck parking brake, can prove detrimental to hub and axle seals, even expediting failure in the most severe of cases.
In any event, a stuck parking brake should be taken seriously, and addressed immediately. If you do not feel up to the task of addressing your vehicle’s parking brake-related issues, a tow truck should be called, and repair should be scheduled at a qualified service center.
Can the Parking Brake Be Manually Disengaged?
In a number of cases, a stuck parking brake can be manually disengaged, in order to facilitate further vehicle operation. However, doing so requires one to understand the manner in which their vehicle’s parking brake operates and the exact cause of their parking brake’s malfunction.
However, for newer cars with electronic parking brakes, manual disengagement is often not possible by the car’s owner as the computer ultimately controls the system unlike mechanical parking brakes.
The next section explains how manually release a traditional parking brake.
How to Release a Stuck Emergency Brake
If a vehicle’s parking brake has become frozen, heat must be applied to free any binding that is discovered.
In many cases, simply allowing one’s vehicle to idle for a prolonged period, will create enough exhaust heat to remedy the situation at hand. However, this process can also be expedited by providing a little well directed heat from a hand held propane torch.
In the event that corrosion is to blame for parking brake related difficulties, the repeated application of a vehicle’s hydraulic brakes can often provide relief. However, intervention via mechanical means might be necessary.
In certain cases, several well-directed sprays of white lithium grease or penetrating oil, followed by the application of pressure to a vehicle’s brake cable can prove beneficial.
In the most extreme case, one might be required to attempt disengaging their vehicle’s e-brake by hand. This typically involves applying tension to a vehicle’s parking brake cable by hand, at or near the point at which two sections of parking brake cable adjoin, or where the parking brake itself meets its corresponding linkage.
This can be done by pulling upon the cable with a set of vice-grips while prying it from its retainer.
When to Call a Professional
Sometimes, troubleshooting and fixing a stuck parking brake requires the assistance of an expert and that’s just how it goes no matter your DIY repair skills.
If you’ve tried methods such as warming up your car’s engine to melt ice or gently tapping the wheel, but your stuck parking brake still hasn’t budged, it’s time to call a tow truck. Don’t risk forcing it or causing damage to your vehicle — getting a tow to a nearby mechanic is a safer option.
Types of Parking Brakes
There are several different types of parking brakes currently in service along today’s roadways. The exact type of parking brake that a vehicle comes equipped with varies by manufacturer, as well as by model.
The following are the most common types of parking brakes in use today.
Drum-Style Parking Brake
Vehicles equipped with drum brakes utilize a specialty cable-driven lever to engage the assembly’s brake shoes, wedging them against the inner diameter of the brake drum itself.
This occurs without any actuation of the assembly’s wheel cylinder, as is the case during typical hydraulic brake applications.
Disc/Drum Hybrid Parking Brake
Many vehicles featuring 4-wheel disc brakes now utilize a separate drum-style parking brake assembly, mounted within the hat of a rear brake rotor. This cable-driven assembly operates similarly to that utilized by standard drum brake-equipped vehicles.
When the parking brake cable is tensioned, internally-mounted brake shoes contact the interior surface of the rotor’s hat, thereby implying friction.
Modified Disc Parking Brake
A number of newer vehicles equipped with 4-wheel disc brakes feature a modified disc brake design, which uses a vehicle’s rear calipers as the source of the application.
Parking brakes of this variety rely upon the actuation of a cable-driven lever, to force a caliper’s brake piston outward. This is in direct contradiction to a service brake application, which is completed through the delivery of hydraulic force.
Electronic Parking Brake
In recent years, a number of vehicles have begun to employ the use of electronically actuated parking brakes. This electronic mechanism is integrated into a vehicle’s rear brake calipers.
Upon application of a switch or button, an electric motor forces a brake caliper’s piston outward, thereby causing the corresponding brake pads to make contact with their rotor.