Rather than trying to cast those bushings, I think I'd machine them out of a piece of Teflon round stock, two pieces that include the "washer" section, pressed into the housing from each side. Then press the steel sleeve into the middle.
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!