How does an Emergency Brake Work?

In a car with an automatic transmission -- the system of gears that changes at various driving speeds -- the "Park" setting helps keep the vehicle from rolling.
The emergency brake is designed to function even when there is total brake failure.
In cars with a manual transmission, the emergency brake is used as a parking brake.
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  • Written By: Mary McMahon
  • Edited By: Bronwyn Harris
  • Last Modified Date: 07 October 2015
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An emergency brake is a backup braking system designed to function even when there is total brake failure. It works through purely mechanical means, and is independent of the hydraulic system which controls the brakes normally. In addition to being used in emergency situations, this brake is also used as a parking brake, to prevent the car from rolling away, should it slip into gear. Like all parts of the braking system, it should be checked regularly to ensure that it is in good working order.

To activate the emergency brake, the driver typically pulls up a lever or pushes a pedal in the front of the vehicle. Steel cables attached to the brake run to the rear brakes of the car, which are typically drum brakes. When the cables are tightened, they pull the brake shoes into contact with the drum of the brake, bringing the car to a stop. In the case of disc brakes, the brake cables are attached to a small screw mechanism that pushes a piston into contact with the brake pads, forcing them to grip the brake rotor. Typically the brake has a self-locking system, meaning that the driver must lower the lever or move the pedal to take the brake off.


In a situation where a driver experiences total brake failure, the emergency brake can be used to bring the car safely to a stop. In this situation, the brake should be set slowly, rather than yanked, to prevent fishtailing or spinning out. Some drivers use an emergency brake deliberately for this purpose, but this sort of driving should only be undertaken by drivers who have been well trained, as it can be highly dangerous.

In a car with a manual transmission, the emergency brake is used as a parking brake on a regular basis, and some drivers may also use it at stop signs. Because of the frequent use, the brake is kept in good working order, although the cables may need to be periodically tightened. In cars with automatic transmissions, however, some drivers do not set the emergency brake as a parking brake. In addition to being unsafe, this also can lead to buildup of rust and corrosion in the brake cable, which could result in cable failure in an emergency.

Drivers should set the parking brake whenever they park, and they should also periodically inspect their emergency braking system or have it inspected. During an inspection, the condition of the cables should be checked, and they should be moved or tightened if necessary. In addition, the wear on the brake pads can be inspected at this time, to ensure that they do not need to be replaced.


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Post 10

Is it possible to drive with the e brake on, without using the gas pedal?

Post 9

I've seen cars that did not have their parking brakes engaged roll down hills and driveways on four different occasions. They either smashed into other cars or, on one occasion, into a house, and the driver of that one was almost killed trying to jump back into his vehicle to stop it.

Just this year, an old man left his car in drive, got out of his car and held the door for me at the post office. As we were standing there, his car jumped forward and drove itself toward the plate glass door of the post office. Only the curbstone stopped it from disaster. Engage your parking brake every time, whether you have a manual or an automatic. It provides an extra safety net in case you space out.

Post 8

Should my emergency break lever be extra hard to pull up? I recently had what they called preventive maintenance done on the rear breaks while they were replacing the front rotators.

Post 7

No damage can result from leaving the emergency brake on while driving. The engine may have to rev higher to push the car along the road. The emergency brake forces the rear brakes to work. Thus stopping your car. If you keep driving with the E-brake on the only thing you will have to fix is replace your brake pads or rotors sooner than usual.

Post 6

For approximately one mile I drove slowly with emergency brake on. I was not feeling well and was distracted. I am concerned about damage to vehicle.

Post 4

when parking the car in an enclosed garage, should you put the emergency brake on or not?

Post 3

Hi Everybody

I am Working on a project for designing a new parking brake. can anybody assist me on how it really works. i want to know the detail of all parts which are involved in the mechanism?

Post 2

Although I'm not an expert (and if something is wrong with your car, you should go see one), I think the most damage you could do is to the break. You may find it not working quite as well as it used to...

Post 1

what damage if any can happen if you notice that the emergency brake was left on while driving? Is there any damage to the motor?

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