"I second Villi's call to replace the bearings."

Oh, Vikki is going to kill you!!

Granted, I have never had a set of front bearings go out on me in the middle of a drive or anything, but I would assume bad bearings would be noticed at other speeds and turns. Maybe not, its just me talking.

68 BLKBRD, yes my friend, you have opened a can of worms and must now check everything our folks have posted as possible solutions!! And of course we want to hear what you finally find as the cause.

bird67conv's idea of the upper CA bushings is a possibility for sure.