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.

How do you fix a locked up brake?

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.

How do you know if your brakes are locked up?

How do you know when your brakes lock up? If you notice that your vehicle pulls to one side, or you smell burning, it could be that one or more of your brakes are locked up or seized.