|Press Fit Bearings|
|Press fit wheel bearings can give you fits because they are pressed into the knuckle, making them much more difficult to replace.
You have two alternatives here: remove the knuckle and use a hydraulic ram to push the bearings out of the knuckle, or buy some special wheel bearing service tools that can do the job with the knuckle in place.
The latter can be a real time saver because you don't have to pull the knuckle. A puller kit can cut the job to about 20 minutes per wheel, and, depending on the application, can also eliminate the risk of damaging the lower ball joint or tie rod end if these parts don't have to be disconnected.
Applications that typically require removing the knuckle or using a wheel bearing puller kit include older Japanese cars, such as 1986-91 Toyota Camry, 1986-94 Toyota Celica, 1987-94 Toyota Corolla, 1992-94 Lexus ES300, 1985-94 Nissans, 1988-94 Mazdas and 1986-94 Honda and Acura. Others include 1973-94 Audis (except 100LS), 1985-88 Chevy Nova, most 1979-90 Chrysler FWD cars, 1995 Chrysler Neon, 1991-94 Saturns, 1975-94 VWs, plus various Ford FWD cars.
|Captured Rotor Wheel Bearings|
|The hardest ones to replace are typically the front wheel bearings on older Japanese FWD cars with captured rotors. Besides having to pull the hub to remove the rotor, the bearings may have spacers or shims inside the knuckle housing that must be measured and sized to get the proper fit when new bearings are installed.
The basic service procedure for press fit bearings goes like this:
1. Loosen the hub nut with the wheel on the ground.
2. Raise the car and remove the wheel.
3. Remove the hub nut and discard it (use a new one for installation).
4. Remove the brake caliper from the knuckle.
5. If the rotor is the captured variety behind the hub, use a hub puller to remove the hub and rotor. Otherwise pull off the rotor.
6. If the knuckle has to be removed, mark the position of the cam bolts on the struts (if used) to maintain wheel alignment. Then disconnect the tie rod end and lower ball joint from the knuckle. Remove the knuckle and use a hydraulic ram to carefully press out the old bearings. Note the position of any spacers or shim~ that are used, and measure the thickness as required to maintain the specified clearances. Clean the knuckle cavity and inspect for any damage. Then install new grease seals, bearings, spacers and/or shims as needed.
7. If you have a wheel bearing hub puller kit that can extract the bearings without having. to remove the knuckle, mount the puller and push or pull the bearings out of the knuckle using the appropriate adapters.
8. When you install the new bearings, use a new grease seal and be sure you position any fingers, spacers or shims that are required in the right position to maintain proper clearances.
Locking rings must be replaced by new ones during mounting because they are often seriously damaged during dismounting. The locking rings should be considered as safety features, as they help to secure the position of the bearing.
It is nearly impossible to give a general torque specification for a locking nut. There can be large differences depending on bearing type and housing. Use the torque given by the car manufacturer's recommendations.
The key to FWD wheel bearing service is to do it right the first time, and to do it efficiently without wasting a lot of time. A wheel bearing puller kit can do just that and allow you to finish the job more quickly.