Wheel bearing replacement in a GM A-body with JM4 brakes

A common problem in many FWD GM cars with ABS is water intrusion into a front wheel bearing, causing the wheel speed sensor to fail. The ABS malfunction indicator lamp is turned on, and a code 32 (left) or 33 (right) is set. The solution is to replace the hub and bearing assembly.

The parts and directions on this page should apply to 1991-1999 H-bodies, 1992-1999 C-bodies, 1992-1996 U-vans, 1992-1996 E-bodies, and 1994-1996 A-bodies.

        Part numbers
General Motors SPO
AC Delco
Chicago Rawhide / SKF / NAPA
Federal-Mogul / BCA / National

  1. Loosen the wheel lug nuts and the axle nut. To loosen the axle nut, you will need a 34 mm or 1 5/16 inch socket and a BIG breaker bar.
  2. Raise the car.
  3. Remove the wheel.
  4. Disconnect the brake line clip from the strut. Remove the brake caliper and brake rotor. The caliper does not need to be disconnected from the brake line; use a piece of wire to hang it out of the way. The caliper mounting bolts have 3/8 inch Allen heads.
  5. Remove the axle nut.
  6. Put the car in neutral.
  7. Using the access holes in the hub, use a T-55 Torx socket to unfasten the hub/bearing assembly from the steering knuckle. Disconnect the electrical connector and remove it from its support.
  8. Use a crowbar to pry the hub/bearing assembly from the steering knuckle. The axle should easily slide out of the hub. If it does not, use a large puller tool to push it out. Here's what the old bearing looks like inside.
  9. If you look at the replacement hub/bearing assembly, you will notice that the oil seal is already attached. But chances are that the old seal will stick to the steering knuckle when you remove the old bearing. Use a pliers, a screwdriver, a small hammer, or whatever to get the old seal out.
  10. Put the new hub/bearing assembly in the steering knuckle in the same orientation that the old one had. Use the three mounting bolts to drive it fully in (tighten one turn, proceed to the next bolt and tighten one turn, and so on until the assembly is fully tightened). Torque the bolts to 85 N·m. Do not forget to reinstall the support for the electrical connector before putting the bolts in.
  11. Hand tighten the axle nut.
  12. Plug in the electrical connector and attach it to its support.
  13. Reinstall brakes, brake line clip, and wheel.
  14. Lower the car.
  15. Tighten the axle nut to 140 N·m, then turn 20° farther.
  16. Tighten the wheel lug nuts; reinstall wheel cover or center cap.

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