Of all the mechanical arts, I can say with some degree of authority that dealing with hub bearings, the little rotating parts that let your wheels turn, is by far the filthiest.
If a tune-up is like preparing a gourmet meal, working on bearings is scraping the dishes.
These particular examples were flooded with salt water, which not only sealed their fate but beaded up admirably in the hub's consommé of funk.
So we cleaned out the *old* funk, wiping our hands repeatedly with half a roll of paper towels, then installed the new, shiny, precision-engineered bearings and proceeded to slather them with *new* funk, which comes in a tub and is probably just relabeled Crisco.
Oh, and this is after several minutes of precision-engineered manipulation of the machinery, consisting of pounding the bejeezus out of a 4x4" block of wood with a mallet.
Bearings are fascinating, to me at least, because they're machined to within thousandths of an inch, and can spin through thousands of revolutions under thousands of pounds of weight, without crumbling or overheating (unless you get 'em wet), but are installed and removed by pure press-fitting. You just kind of jam those suckers into where they need to be, and mount a wheel on them. No bolts hold them in place or anything. They stay put indefinitely.
In fact, the hard part is getting them *off*, hence the mallet.
We did get it, though. Of course. Tom and Jack are not the types to give up on a project, ever.
Learn more about these revolutionary devices here: http://science.howstuffworks.com/bearing.htm
And stay tuned for me to blab on about mechanical optimism versus pessimism, and how it actually might be better to be cynical, later, when I'm not tired and haven't already blabbed too long anyway.