What Causes Brake Lock-Up

The brakes on your vehicle are certainly one of its most important safety features. So, when they apply on their own or lock up when you need them most, it can be both dangerous and send your heart racing. Here’s why some brakes lock up and what to do if it happens to you.


Why Brakes Lock Up

There is a long list of reasons that one or all of the brakes on your vehicle might lock up. These can include an overheated braking system, using the wrong brake fluid, damaged or broken parts (calipers, brake pads, pistons, rotors, or others), a defective ABS component, broken parking brake, and more.

While diagnosing a brake issue is important, nothing else matters in the moment when you’re dealing with a lock-up. When your brakes lock up, it often boils down to two scenarios: locking up when you least expect it (and have not applied pressure to the brake pedal), or when you hit the brakes hard.

We’ll call the first scenario brake drag or self-applying. Even though you may not have pressed on the brakes, residual hydraulic pressure can cause the brake calipers to activate and lock. This is the most common form of lock-up on the road today. Don’t ignore this problem as it can quickly lead to mechanical failure of other parts of your braking system.

The second type can be called brake lock-up. This can happen when you are both braking hard to avoid an accident, or braking gently to glide to a stop. Essentially, the force of applying the brakes (even lightly) can activate the full stopping-power of your brakes – bringing you to an abrupt and less-than-safe stop. You might even skid. When this happens, you can expect steering and control of your vehicle to be extremely difficult.

See our Complete Guide to Disc Brakes and Drum Brakes for more on these types of systems, as well as our Brake Service FAQ.


How to React With a Lock-Up

Whether you’re experiencing brake drag or brake lock-up, get to your local Les Schwab as soon as safely possible. Our technicians will ask what wheel or wheels seem to be locking up and when. Any information you can provide will help with the diagnosis and repair.

But, when you’re on the road, and a lock-up happens to you, you have three choices that could help you avoid an accident.

  1. Apply pressure to the brakes and try to gain as much control as possible. If your vehicle has an Anti-lock Braking System (ABS), you’ll feel some feedback in the pedal and could hear a mechanical-type noise as your vehicle comes to a stop. The feedback is the ABS working to keep the wheels from locking up and preventing you from skidding.
  2. Take your foot off the brake pedal so your wheels can get enough traction to possibly unlock momentarily. Then reapply pressure to the brake if needed.
  3. Repeatedly (and quickly) press the brakes over and over until the brakes either disengage or bring you to a safe stop.

Les Schwab Knows Brakes and Safety

When you experience braking problems, or just want to have your brakes professionally checked or repaired, get to your local Les Schwab. Our technicians understand both disc and drum brakes, as well as how all the interconnected components work together for your safety. Schedule your appointment, or just stop by and we’ll help you get safely back on the road.


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