OK- - - -it looks like all four wheel cylinders are rebuildable. The pistons needed quite a lot of cleanup- - - -badly corroded and gunked-up with congealed brake fluid, but they responded to some polishing on the lathe. Next comes honing the housings and reassembling with new rubber cups. The dust caps are the only things that aren't salvageable, so at some time in the future it would be a good idea to locate some correct rebuilding kits and swipe the dust boots out of them. This rehab is not intended to be a full rebuild- - - -just a way to make the truck safe to operate on the way to Denver!
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!