I swapped the front wheel hubs/rotors from my 85 300TD into my 83 300SD a few years back, and since then (without realizing the cause), heard a light humming/thumping noise in my front driver's wheel/hub. On a recent road trip, the inner bearing disintegrated and I had to tow the car home.

I suspect now that I tightened the spindle locking nut TOO tight. When free spinning, the wheel definitely slowed down pretty fast, like there was serious resistance. After maybe 2 years, some noises coming and going, the bearings became stressed enough to the point of breaking (especially when the other wheel moved more freely). I'm wondering if someone can confirm this possibility.

I was wondering if there's anything special involved with putting the new bearings on the hub. I tried doing it the other day with simply using the locking nut and hub as a "press" to fully tighten the hub and bearing, then backed off on the locking nut until it rotated as freely as the other wheel. I drove it for about 60 miles and it definitely sounded differently than before, but it still sounds like a light low humming noise. Maybe that's normal to an extent.

Is there anything special to the process of adjusting the locking nut or getting the bearings on?