I've read quite a bit of conflicting information about the rear wheel bearing problems with late 90's early 2000's Subarus. My problem was on a 2000 Forester, right side rear, 147K miles. I purchased aftermarket bearings from NAPA, Part# SKF GRW175.
Upon receiving these, the first thing I noticed, was that there was no visible grease in the rollers, so I opened the assembly, and found a very small amount of a clearish yellow grease that was about the consistency of Vaseline. When I asked the guy at NAPA about it, he said they were pre-lubricated with the correct amount of grease, and I should put them in as they are.
I don't think so. The grease in the assembly did not look like any quality bearing grease I ever used, and the bearings were not properly packed. In fact, they weren't packed at all. I blew the grease out of the bearings and practically nothing came out. I cleaned out the Vaseline with brake parts cleaner and compressed air (careful) and properly packed the bearings with Moly-Graph grease.
Another aspect of this job that I haven't gotten to yet is how to set the clearance. In the old days, you would take the opposing tapered roller bearings carefully to zero end play with the adjusting nut, then back it off to provide a small amount of end play. if you press the assembly together, there cold end play should be correct, but does anyone out there ever verify this? If so, does anyone have a method of doing it?
I read about folks having multiple failures of these bearings after installing aftermarket parts, and even OEM bearings. The items I addressed above may be contributing to this high incidence of failure. Having gone through the lateral link bolt removal hell, I never want to do this job again.