It is the Ford wheel hub and bearing that makes it possible for the wheels to turn with the least amount of friction as possible while supporting the weight of your vehicle. If there is any problem with the wheel hub assemblies, the feel in the car or truck can be a rough but subtle ride and cause all occupants to be on edge. There are four sets of Ford wheel hubs and bearings on all car and trucks of this type. The bearings are packed in grease from the factory and sealed in the wheel hubs. This grease must be routinely replaced over the life span of the vehicle. This is generally done during a routine brake job. The only protection the wheel hub and bearing sets on your Ford vehicle have from the dirt and debris on the road are small little dust caps. These caps are just fitted over the wheel hub ends and generally stay in place unless forced off. With regular packing of grease in the wheel hub bearings, the Ford owner should never have to worry about these components wearing out or causing any type of problem. If the grease is not periodically changed over the life time of the vehicle, the metal to metal contact in the wheel hub and bearing will begin to generate heat. As the bearings and the rollers it contains begin to expand upon being heated, the loud screeching noise will start to coming from the hubs when the vehicle is in motion. The noise is being produced by the increase in friction these components are experiencing on your Ford car or truck. If this is heard, replacement is required for your vehicle to return to going smoothly down the road again.