Wheel Speed Sensor Replacement (C 3500HD)
REMOVAL PROCEDURE
1. Raise vehicle.
2. Remove tire and wheel.
3. Remove brake caliper.
4. Remove the hub and rotor.
5. Remove the splash shield.
6. Remove the wheel speed sensor wire mounting clip (2) attached to the upper king pin cap.
7. Wheel speed sensor wire mounting clip (5) attached to the frame rail.
8. Remove wheel speed sensor cable electrical connector (1).
9. Remove wheel speed sensor to bracket mounting bolts and nuts.
^ It is not necessary to remove the wheel speed sensor mounting bracket (4) unless the bracket is damaged.
10. Remove the wheel speed sensor from the mounting bracket (4).
^ It is not necessary to replace the sensor mounting bracket unless there is visible damage or distortion to the mounting bracket.
INSTALLATION PROCEDURE
NOTICE: The wheel speed sensor used on the C 3500HD models is adjustable by means of slots provided in the mounting bracket. The sensor must be properly adjusted in order to provide the correct air gap between the wheel speed sensor and the tone wheel. If the sensor is not properly adjusted, the tone wheel may hit the wheel speed sensor, or the output from the wheel speed sensor may be low, missing or erratic. Follow the procedure outlined below to properly adjust the front wheel speed sensor.
1. Install the wheel speed sensor to the mounting bracket (4).
2. Install wheel speed sensor to bracket mounting nuts and bolts.
^ Run down the nuts but do not torque. The wheel speed sensor must remain loose and move along the slots in the bracket.
3. Place the front hub and rotor assembly on a flat surface with the tone wheel facing up. Take care not to damage the wheel studs.
4. Mark the position of the rotor relative to the hub so the rotor can be installed in the same position later.
5. Remove bolts attaching the rotor to the hub.
6. Remove the rotor from the hub.
7. Install hub and tone wheel assembly on the knuckle spindle.
8. Install the outer bearing, washer and spindle nut.
Spindle nut to 16 Nm (12 ft. lbs.) while rotating the nut in either direction.
^ Do not back off the nut.
NOTICE: DO NOT use a rigid feeler gage or a wire spark plug gap gage to set the wheel speed sensor to tone wheel air gap as these tools will not result in the correct air gap.
9. Insert flexible shim stock or equivalent between the tone wheel and the wheel speed sensor.
^ The thickness of the shim stock must be 1.25 mm (0.050 in.). The length and width of the shim stock must be sufficient enough to cover the face of the wheel speed sensor. If shim stock is not available, regular notebook or writing paper can be used provided the specified thickness is inserted between the tone wheel and the wheel speed sensor.
10. Press the wheel speed sensor firmly against the shim stock and tone wheel.
10.1. Tighten the left hand lower attaching nut to 13 Nm (10 ft. lbs.).
10.2. Tighten the left hand upper attaching nut to 13 Nm (10 ft. lbs.).
10.3. Tighten the right hand upper attaching nut to 13 Nm (10 ft. lbs.).
10.4. Tighten the right hand lower attaching nut to 13 Nm (10 ft. lbs.) while holding the wheel speed sensor against the shim stock.
11. Remove the shim stock from between the tone wheel and the wheel speed sensor.
12. Inspect that the tone wheel does not contact the wheel speed sensor when the hub and tone wheel are rotated.
13. Install the splash shield to the front anchor plate.
^ Take care to route the wheel speed sensor wire through the opening in the splash shield near the center mounting hole.
^ Tighten bolts to 17 Nm (13 ft. lbs.).
14. Route the wheel speed sensor wire between the splash shield and the knuckle.
15. Install the wheel speed sensor mounting clip to the upper king pin cap.
^ Tighten: the bolt to 17 Nm (13 ft. lbs.).
16. Connect the wheel speed sensor cable electrical connector.
17. Install front wheel hub and tone wheel assembly to spindle.
18. Install rotor to front wheel hub.
^ Take care to line up reference position marks.
19. Install bolts.
^ Tighten bolts to 237 Nm (175 ft. lbs.).
20. Install the hub and rotor.
21. Install brake caliper.
22. Install tire and wheel.