What Your Anti-Lock Brakes Do ABS can improve vehicle stability, steerability and stopping capability. Four-wheel ABS prevents wheel lock-up, allowing drivers to maintain stability as well as steering control during an emergency braking situation.

How the Anti-Lock Mechanism Works When a driver operating a four-wheel ABS equipped vehicle steps firmly on the brake pedal, the system automatically modulates the brake pressure at all four wheels, adjusting pressure to each wheel independently to prevent wheel lock-up. With four-wheel ABS, the driver has improved steering control of the vehicle.

The Difference Between Four-Wheel and Rear-Wheel Anti-Lock Brakes Four-wheel ABS is designed to maintain vehicle stability and improved steerability in emergency stopping situations. Because the braking system in a four-wheel anti-lock equipped vehicle modulates the braking pressure, preventing wheel lock on all four wheels, the driver has improved control over steering.

Rear-wheel anti-lock brakes, found exclusively on light trucks, vans and sports utility vehicles, prevent wheel lock of the rear wheels only. This allows the driver to maintain directional stability and prevents the rear end of the vehicle from skidding sideways. The front wheels can still lock up on rear-wheel ABS systems just like conventional brakes. If that happens, the driver should ease up on the brake pedal with just enough pressure to allow the front wheels to start rolling again, so the driver can steer.

How to Know when Your ABS Is Working Most anti-lock brakes let you know when you have activated your ABS. The driver can notice a mechanical sound and feel some pulsation or increased resistance in the brake pedal. It is important to keep your foot on the brake pedal when you hear noise or feel vibrations. Continue to apply firm pressure.