How do you keep a master cylinder from getting rusty? I know there are gray paints and clears but I assume the first drop of brake fluid will bubble these. Any thoughts? Thanks.

Your right...Brake fluid will ruin the paint. It's simple...don't get brake fluid on the master . I'm real carefull when bleeding the brakes as well, that fluid can't get on anything.

Some more durable finishes might work...powder coating, zinc, zinc dichromate, chrome, etc.

I used DOT 5, Silicone brake fluid... It doesn't hurt the paint, but can't be mixed with older fluids... I did a complete brake overhaul (including lines). Been using it for 9 years, and no problems...

I have also seen quite a few powdercoated... Very durable (I have a bunch of other parts powdercoated)...