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.

A. Install a large C-clamp over the top of the caliper housing and against the back of the outboard pad.

B. Slowly tighten the C-clamp until the pistons are pushed completely into the caliper bores.

C. 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 sensor 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 of corrosion.

18. Using compressed air, remove all debris from the bearing hub surface.

19. Using a clean shop towel, clean the sensor and the 0-ring.

Important:
While the corrosion is drying in the next step, begin performing Steps 3-20 on the opposite side front wheel speed sensor.

20. Apply (spray) two thin coats of the specified rust penetrating lubricant (corrosion inhibitor) listed in this bulletin, to the complete sensor mounting surface on the bearing hub. Allow to dry for 3-5 minutes between coats.

21. When the corrosion inhibitor is dry to the touch (about 10 minutes), apply a light coating of the specified grease to the complete sensor mounting surface on the bearing hub and to the sensor and 0-ring.

22. Remove the temporary plug from the hole in the bearing hub.

23. Install the wheel speed sensor in the bearing hub and install the bolt. Ensure that the sensor is seated flat against the hub.

Tighten

Tighten the wheel speed sensor mounting bolt to 18 Nm (13 lb-ft).

24. Disconnect the front wheel speed sensor connector and place a digital volt meter (DVM) across the terminals of the wheel speed sensor connector. Rotate the bearing at approximately one revolution per second. The minimum reading should be at least 350 ACmVs. If the reading is less than 350 ACmVs, the wheel speed sensor must be replaced. Follow Steps 12-15 for instructions on replacing the wheel speed sensor. This step must be repeated afier the new sensor has been installed.

Notice:
Whenever the brake rotor has been separated from the wheel bearing flange, clean any rust or foreign material from the mating surface of the rotor and flange. Failure to do this may result in increased lateral runout of the rotor and brake.

Important:
If the rotor was removed using the jack screw method, you must ensure that the hub flange is free of nicks or marks caused by this procedure. Remove all raised nicks or marks before installing the rotor.

25. Align the rotor to its original position on the hub and install the rotor.

26. Install the caliper and caliper mounting bracket assembly.

27. Perform the following procedure before installing the brake caliper bracket mounting bolts.

28. Remove all traces of the original adhesive patch.

A. Clean the threads of the bolt with brake parts cleaner, or the equivalent, and allow to dry.

B. Apply threadlocker to the threads of the bolts.

29. Install the caliper bracket mounting bolts. Tighten the brake caliper mounting bracket mounting bolts to the specification listed below.

Tighten

^ 1500 Series vehicles -- 175 Nm (129 lb-ft)

^ 2500 Series vehicles -- 300 Nm (221 lb-ft)

30. Install the front tire and wheel assembly.

Tighten

Tighten the wheel nuts to 190 Nm (140 lb-ft).

31. Complete Steps 21-30 on the opposite side front wheel speed sensor.

32. Lower the vehicle.

33. With the engine OFF, gradually apply the brake pedal to approximately 2/3 of its travel distance.

34. Slowly release the brake pedal.

35. Wait 15 seconds and repeat Steps 32-33 until a firm pedal is obtained. This will properly seat the brake caliper pistons and brake pads.