Anti-Lock Braking (ABS) System Parts

Drivers used to have to pump the brake pedal to avoid wheel lockup and skidding out of control, but that changed when Anti-lock Brake Systems (ABS) came along. ABS systems modulate pressure to the wheel brakes many times per second, far faster than any driver can, preventing wheel lockup so you can maintain control of your vehicle and come to a safe stop. The ABS includes wheel speed sensors, a hydraulic control unit, and an electronic control module.

The reason that pressure modulation is so important is that there is more friction between the road and a wheel that is on the verge of slipping but still turning, than one that is locked up and skidding, and more friction means a shorter stopping distance. Wheels that aren’t skidding also allow the vehicle to be turned, so you can maintain directional control. When ABS is activated, the driver will feel pulsations in the brake pedal.

Although there have been many ABS variations, including systems on light trucks that acted on the rear wheels only, today most vehicles have 4-channel systems that modulate brake fluid pressure to each wheel independently. Sensors that are electronically connected to the control module are located next to toothed rings at each wheel to detect wheel speed. The toothed ring can be mounted on the hub, CV-joint, or axle shaft. During braking, if one wheel slows faster than the others and begins to lock, the module will signal solenoid valves in the hydraulic control unit to reduce fluid pressure to that wheel to prevent lockup.

ABS systems have self-diagnostic capabilities to alert the driver if there is a problem in the system. The control module continuously monitors the system and if a malfunction is detected, it will illuminate the ABS dash warning lamp and a trouble code will be stored. On most systems the ABS will be disabled but normal unassisted braking will remain. Common ABS problems include incorrect air gap between the wheel speed sensor and toothed ring, debris such as metal shavings that collect on the sensor, broken teeth on the sensor ring, damaged/corroded wiring and connectors, and corrosion in the hydraulic unit.

No matter what kind of ABS problem you’re having, we have the parts to get this important safety system back up and operational. We not only have OE spec parts for precise fit and function, but we also offer time and money saving repair solutions like sensor rings that can be replaced without having to replace the entire component, control modules with upgraded transistors, harnesses that can be serviced separately from the sensor, and much more. Many of the components we offer have been “reverse engineered” to eliminate defects that caused the part to fail, so you get a replacement part that is in effect, better than new.