The 2003 Ford Focus comes in a number of different models.There are four different body styles with four different engine sizes. This variation leads to different methods for fixing certain features of the Focus, but not the wheel bearings. The process for replacing the wheel bearings is the same for all models. The process is, however, very difficult and requires expertise as well as specialised parts. The bearings sit in a hub and can only be removed with a press. Expect the replacement process to take about an hour, not including the time to get the bearing pressed out of the hub.
Place chucks behind the rear wheels of your Ford Focus. Loosen the lug nuts on the right wheel. Set the car jack under the chassis of the Focus near the wheel. Raise the Focus until the wheel is off of the ground. Loosen and remove the five lug nuts. Pull off the wheel. Set a jack stand under the chassis near the wheel. Lower the Focus onto this jack stand.
Remove the two 14 mm (1/2 inch) bolts on the rear of the brake caliper bracket. Strap the brake caliper bracket to the suspension coil. Do not let it hang loosely by the brake hose.
Remove the axle nut with your deep axle socket, 14 mm (1/2 inch) ratchet, and extended breaking bar. Apply as much force as you can to remove this nut, which is very tight. Remove the nut with an air-compressed hammer if you have one instead.
Pull off the rotor from the wheel bearing hub with your hands.
Remove the four 14mm (1/2 inch) bolts securing the wheel bearing hub to the disc.
Loosen and remove the anti-lock brake sensor ring from the wheel bearing hub assembly with your wrench and hammer.
Set the wheel bearing puller on top of the bearing. Insert three bolts into the bolt holes of the bearing. Attach the 17mm (3/4 inch) socket and ratchet to the puller. Loosen and remove the wheel bearing hub from the assembly.
Take the wheel bearing hub to a professional mechanic who has a hydraulic press. Have the mechanic press the current wheel bearing race off of the wheel bearing hub and install the new one to the hub.
Reseat the wheel bearing hub to the wheel bearing hub assembly. Place the wheel bearing hub flat on the ground. Place the assembly over it. Place a deep socket over the assembly. Hit the socket hard with a mallet until the assembly is secured onto the wheel bearing hub.
Resecure the anti-lock break sensor ring onto the wheel bearing hub assembly. Insert the wheel bearing hub assembly into the disk. Secure it in place with the four bolts you removed earlier. Replace the rotor. Resecure the brake caliper over the rotor. Tighten back on the central axle nut. Replace the wheel. Lower the Focus to the ground.