K128914ORX
ABS Modulator Valve
Bendix

Operating within a vehicle's anti-lock braking system, the hydraulic actuator modulates brake pressure at each wheel based on commands from the ABS control module and wheel-speed sensors. The device interprets sensor data and uses solenoid-controlled ports to move a precision spool inside the valve body, quickly increasing or reducing hydraulic pressure to individual brake circuits as needed. This rapid, targeted modulation prevents wheel lock, preserves steering control, and helps maintain traction on wet, icy, or uneven road surfaces. The design emphasizes durability: rugged housing and seals that withstand brake fluid across a wide temperature range and vibration inherent to heavy-duty service. Tight leakage control and fast response time minimize pedal pulsation during ABS events and improve predictability for the driver. From a maintenance perspective, the unit provides clear diagnostic signals when a fault occurs, enabling quicker pinpointing of issues such as spool sticking or port leakage within the modulator system. Proper replacement should follow Bendix service procedures, including checking compatibility with the specific ABS module and ensuring correct orientation of the hydraulic lines and connectors. In practice, many fleets replace related components as a set to ensure balanced braking characteristics across axles. When selecting a replacement, verify the latest service bulletin and use manufacturer-approved seals and adaptors for reliable long-term service. Source One Parts Center.