Wheel Cylinder Lube ?

[Green Machine]

No - I'm not looking for blinker fluid either ! And certainly not GREASE !

Yes I know new ones are cheap, but I bought some rebuild kits for some good wheel cylinders that had been replaced by the PO at some. (I am cheap sometimes).

Used to be the kits came with a little capsule of lube for the cups and pistons, well these didn't have any lube, so I just cleaned and honed them and used a little brake fluid for assembly. I didn't install them but set them aside for a future project for about 6 months. Happened to check them one day and WTF, they had rust inside already, the brake fluid sucked in moisture and rusted again, so I cleaned and rehoned them, had to use brake fluid agian and put them in plastic bags now.

I think if I would have had the proper lube, that is fluid and rubber compatible like they used to put in the kits, I would have been ok. And even later when I install them, I am afraid the rust may return.

Is there a specific cylinder lube available for those that still like to rebuild cylinders if they are not too bad ? They must put something on the new ones you buy, sitting one the shelf at the parts store they don't rust.

Thought I seen that Castor Oil is a component of brake fluid and won't attack rubber, its cheap and available and sure looks like the stuff that used to be supplied in the wc kits. Will that work or what should I use ? I hate brakes that pull becuse the cylinders start to rust.

Thanks
GM