1999-2002 Chevrolet Silverado Front Wheel Speed Sensor Corrosion

1999-2002 Chevrolet Silverado Front Wheel Speed Sensor Corrosion

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Service Procedure The following procedure provides instructions for repairing a corrosion condition where the front wheel speed sensor mounts on the front wheel bearing assembly. 1. Raise the vehicle on a suitable hoist and support as necessary. 2. Remove both front tires and wheels. 3. Compress the front brake caliper pistons. 3.1. Install a large C-clamp over the top of the caliper housing and against the back of the outboard pad. 3.2. Slowly tighten the C-clamp until the pistons are pushed completely into the caliper bores. 3.3. Remove the C-clamp from the caliper. Important: It is not necessary to remove the front brake caliper from the bracket when removing the bracket in the next step. 4. Remove the two bolts that attach the front brake caliper mounting brackets to the knuckle. Notice: Support the brake caliper with heavy mechanic’s wire, or equivalent, whenever it is separated from its mount, and the hydraulic flexible brake hose is still connected.

Failure to support the caliper in this manner will cause the flexible brake hose to bear the weight of the caliper, which may cause damage to the brake hose and in turn may cause a brake fluid leak. 5. Remove the brake caliper and bracket as an assembly and support it with heavy mechanic’s wire or equivalent. DO NOT disconnect the hydraulic brake flexible hose from the caliper. 6. Mark the relationship of the rotor to the bearing hub. 7. If equipped, remove the rotor retaining push nuts from the wheel studs 8. Remove the rotor. 9. Remove the bolt (1) that attaches the wheel speed sensor to the bearing hub. Notice: Carefully remove the sensor by pulling it straight out of the bore. DO NOT use a screwdriver or other device to try to pry the sensor out of the bore. Prying will cause the sensor body to break off in the bore. 10.Remove the wheel speed sensor from the bearing hub assembly. Important: The mounting surface on the sensor must be flat in the next step in order to be mounted correctly on the bearing hub assembly. If the mounting surface on the sensor is warped or bent, the sensor must be replaced.

11.Inspect to see if the mounting surface on the sensor is flat. Check the mounting surface on the sensor head for flatness by placing it on the edge of a metal machinist’s scale or other suitable straight edge to measure the flatness. Check the sensor for flatness in multiple positions/directions (minimum 3). • If the sensor mounting surface is NOT flat (1), the sensor must be replaced. Proceed to the next step and replace the sensor. • If the sensor mounting surface IS flat (2), the sensor IS to be reused. Proceed to Step 16. 12.Remove the wheel speed harness mounting clips from the knuckle (4) upper control arm (3) and frame (2). 13.Disconnect the wheel speed harness electrical connector (1) from the vehicle wiring harness. 14.Connect the new wheel speed sensor harness electrical connector to the vehicle wiring harness. 15.Attach the wheel speed sensor harness to the frame, upper control arm, and the knuckle. 16.Temporarily plug the wheel speed sensor hole (1) in the bearing hub to prevent debris from entering it when you clean it. Important: All rust and corrosion must be removed from the wheel speed sensor mounting surfaces on the bearing hub in the next step. 17.Using a wire brush, sandpaper, emery cloth, scotch brite, or equivalent, thoroughly clean the wheel speed sensor mounting surface (2) on the bearing hub to remove any rust or corrosion.