Every since I heard Lieberman announce that he "has personally checked Senator McCain's bearings..." I can't get this image out of my head.

I'm fairly certain that Joe was going for a "under the hood" analogy. But, what I'm hearing now is more bellow the belt, as in Joe saying to John:
 "cough"
"yep, bearings still intact"
"my goodness, those are some big bearings!"
"are these brass ones?"

Joe, I know you thought it was cute, but you've seriously ruined my morning coffee break.