My C3 spent 24 years in a climate-controlled garage (allegedly.) Some knowledgeable folks have told me that the grease in the rear wheel bearings is probably solid and not really lubricating the bearings. I have no symptoms, but I haven't driven it a lot since acquiring it a few months ago. The worst case scenario is that one of the wheels could seize up and possibly break the spindle, thus losing the wheel.
Joel Adams
C3VR Lifetime Member #56
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"