I just recently purchased a 1993 Lumina Euro. When it's being driven there is a very loud noise coming from the back end of the car. Could this be a wheel bearing? If so, can the bearing itself be replaced, or does the entire hub need to be replaced. Thanks

Welcome aboard.

If the noise can be described as a grinding, loud humming/buzzing, or howling, it may well be a wheel bearing. The rear hubs have an integral pair of roller bearings. If you have a press and bearing heater/mounter, you can replace the bearings. However, remanufactured hub assemblies may be just as cost effective.