That "cushion" is rubber and it's probably unobtanium. When I rebuilt one of those shafts a little over a year ago, the original one was still in reusable condition. The only way I can think of to fabricate a new one would be to use a piece of large diameter Teflon round stock, and make interlocking halves of the cushion with a lathe.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!