On Thursday, March 3, 2016 at 8:24:40 AM UTC-5, wrote:
Let me know the easy steps to replace the rubber on this part with an
O-ring from the hardware store.


Then, replace it with a flat O-ring out of a catalog, McMaster-Carr and/or any of a dozen other sources. Don't forget to re-lubricate the bearing...


This is an extreme nitpick but maybe somebody would like to know.

To the general population an O-ring is any washer or gasket with a round cross section. I'm not so sure anybody thinks a flat gasket is actually an O-ring, but most people think any round one is.

Not so. Mechanical engineers have a technical definition of the O-ring, and it is not shape but function.

See he
http://www.row-inc.com/sizes.html

If the gasket of circular cross section is sized so that it can rotate inside that groove, then and only then is it an O-ring.

Okay, nobody cares. But now you know.

(just try confusing a magazine and a clip on a firearms forum, and you'll see what abuse you get)