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John, I'm curious why you said to clean new cylinders. I have never done that. Always just put them in right out of the box.
I learned to clean them first because the wheel cylinder, inside and out is coated from the factory with an anti-corrosion goo, like cosmolene, and that could gum up the action of the cylinder. If you are using DOT 3 there is enough solvent property in the fluid to eventually get through the coating, but I was taught to get everything nice and clean, then coat (lubricate) the parts with the fluid you intend on running the (rebuilt) brake system on. We did a lot of silicone fluid conversions as part of the whole-system overhall, and the DOT-5 silicone may not have dissolved the cosmolene-like stuff. It's just all about having everything in optimal operating condition at the end of the job. I did this "whole system" approach to my '63 Chevy II about five years ago, I replaced all of the rusty (Michigan car) hard lines with brand new pre-bent stainless lines, new flex lines, New wheel cylinders and new master, and I dissassembled and cleaned all four wheel cylinders and the master painted the exterior bare cast iron on all those components, then reassembled, coating the parts with DOT-5 silicone. I will be doing the same with my Packard, possibly this winter, except I think that I will use DOT-3 owing to the problems with the 2-way (three post) OE brake light switch. I usually prefer silicone brake fluid, but DOT-3 works fine, you have to keep an eye on it, and it's a good idea to drain and refill the system about every 10 years when running it.
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