What Should I Do When My Brakes Lock?

By: Ryan Johnson

If you slam on your brakes and they lock up, you could burn a lot of rubber. See more brake pictures.
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­You're speeding over a patch of black ice or wet leaves when suddenly you try to stop -- and nothing happens. Instinct tells you to slam on the brakes, but that will just cause them to lock up, leaving you sliding down the street.

This used to be a common problem before anti-lock brakes (ABS) became popular. Non-ABS brakes lock up when hard, steady pressure is applied. If you stop fast enough to have your tires screech on the road, chances are your brakes will lock. If you're driving a vehicle that does not have ABS brakes, as soon as you feel the brakes begin to lock, release brake pressure and pump the brake until you come to a stop [source: Car Talk]. Pumping requires pushing and releasing the brake pedal multiple times in quick succession.

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In an ABS-equipped vehicle, you'll feel a pulsating in the brake pedal during hard stops, or if the vehicle loses traction. This is perfectly normal, as the brake system is pumping the brakes for you, freeing up any locked wheel and leaving you in control of the vehicle. There's nothing wrong with the pulsating brakes. Don't release them because the car is doing the work for you [source: Ofria].

Anti-lock­ brakes usually don't lock up unless there's a brake problem. Some of the brake issues that can cause ABS brakes to lock up include bad brake pads, calipers on disc brakes, cylinders on drum brakes or wheel bearings.

­Identifying any brake problems is of the utmost importance. When brakes lock up, the vehicle may veer sharply to the left or right, and the back end may fishtail causing the driver to lose control [source: Car Talk]. If this happens while you're driving, pump the brakes consistently until you come to a complete stop, and get the car to a mechanic as soon as possible.

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Brakes Locking Up FAQ

What should you do when your brakes lock up?
If you are driving in the middle of the road and your brakes lock up, try to find a safe spot to pull over. Pumping the pedal can be useful as it builds up the pressure. Don't turn your car off until it completely stops on its own.
Can a master cylinder cause the brakes to lock up?
A master cylinder can be one of the major reasons why your brakes lock up while you are driving. Get your vehicle to a mechanic immediately if such a situation arises.
What does it mean when the brake pedal is hard to push down?
The lack of vacuum pressure can make it difficult to push the brake pedal down. Get your brakes checked immediately to resolve the issue.
Why do my brakes lock up when it's wet?
When the brake shoe absorbs external moisture and becomes wet, it causes your brakes to lock up, hardening them in the process.
What causes one front brake to lock up?
Any problem with the caliper can cause one brake to lock up. It can happen either because of a locked-up caliper piston or a stuck caliper slide pin.

Lots More Information

Related HowStuffWorks Information

  • Car Talk. "Dear Tom and Ray." 11/1994 http://www.cartalk.com/content/columns/Archive/1994/November/13.html (Accessed 11/06/2008)
  • Car Talk. "Dear Tom and Ray." 12/1994 http://www.cartalk.com/content/columns/Archive/1994/December/12.html (Accessed 11/06/2008)
  • Ofria, Charles. "A Short Course on Brakes" The Family Car. (Accessed 11/06/2008) http://www.familycar.com/brakes.htm
  • Rose, Jim. Mechanic. Personal interview. Conducted 11/02/2008

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