I see master cylinders for them on ebay fairly regularly. Kits for them run pretty high.
I think any fluid that meets the DOT5 spec is probably OK. Whatever is cheapest is
probably best for flushing. I think I might hesitate to use alcohol because it has no lube
properties. If you suspect a lot of non-suspendible stuff in the calipers you might want
to exercise them by putting in pad plates with no friction stuff on them to fully extend
the pistons and alternately brake and push the pistons back in a couple times, having the
bleeders open when pushing the pistons back in. This is not as good as disassembly
but it is a LOT quicker and easier and may be pretty effective.
When the fluid is coming out pretty clean you might want to finally fill with a better brand
(assuming you find a difference in price).
If you get a MC on ebay look closely at the pic to make sure you get the right one.
One has a tubular snout sticking back out of the piston - that fits the coffee can booster,
used on the later 1800s and 164 and a few 140s, while the heavier one without the snout fits
the "pancake" booster used on most of the 140s.
--
George Downs, Bartlesville, Heart of the USA!