To service the RABS I and II systems, start by disconnecting the negative battery terminal. For RABS I, locate the module to the right of the brake pedal and under the upper dash panel; for RABS II, find it behind the glove box. Disconnect the wiring harness from the module, remove the retaining screws, and take out the module. Verify the warning light's proper operation. To work on the RABS Hydraulic Control Valve (HCV), locate it on the left frame rail behind the cross member. Disconnect brake lines and the wiring harness, remove the retaining nuts, and take out the valve. Reinstall it, bleed the hydraulic system, and check the warning light. For the RABS Speed Sensor, find it on the rear differential housing, disconnect the electrical connector, and remove the sensor using a hold-down bolt. Inspect and clean the sensor pole piece and O-ring if reusing. Installation is the reverse of removal. To replace the RABS Speed Sensor Ring, disassembly of the differential is necessary; professional repair is recommended if the ring has damaged teeth. For the Bronco's Four-wheel ABS system, disconnect the battery cable and locate the Hydraulic Control Unit (HCU) in the engine compartment. Disconnect the electrical connectors and lines, remove the retaining nuts, and take out the HCU. Reinstall it and have a professional shop bleed the HCU. For the ECU Module, disconnect the battery cable and locate the ECU at the left front fender apron. Disconnect the electrical connector, remove the ECU from the bracket, and reinstall it. Verify the warning light's proper operation. To work on the Wheel Speed Sensors (front), locate the right or left sensor on the steering knuckle(s). Disconnect the electrical connector, remove the hold-down bolt, and take out the sensor. Reinstall it and check the warning light. The process for the Wheel Speed Sensor (rear) is similar to the RABS system. To replace the Speed Sensor Ring (front), remove the affected wheel, caliper, rotor, and hub assembly. Using a three-jaw puller, remove the speed ring from the hub and replace it with a new one. Verify the warning light's proper operation. For the Speed Sensor Ring (rear), professional repair is necessary due to its location and complexity of disassembly.
Posted by FordPartsGiant Specialist 
