Fixing to replace my master cylinder. Raw cast iron, I’d like to paint it before I put fluid in it, once any fluid gets in the pores it’s just about impossible to get paint to stick. Any ideas about maybe cleaning it first, and any suggestions on paint ? Rattle can, brush on, dip it? Just don’t want it rusting after it’s put on. I know brake fluid will eat paint, had a hard time with the current master cylinder that I painted after the install. Clear or cast look is what I’d rather have, black as a second choice.
I painted both of mine with clear mag wheel paint when they were new. Also did my front calipers with the same clear, and all of them still look great. No prep prior, just shot the clear on and installed them.
I've done several. Scrub it good with lacquer thinner. Scuff with a red 3M scuff pad. Wipe down again with lacquer thinner. Paint using Dupli-Color Gun Metal Gray (or any cast color of your choice) and call it good. If you do spill brake fluid on it, touch it up by repeating the process.
I have painted them using Dupli-Color caliper paint kit with very good results. ps, it was the brush on kit, not the spray cans.
I normally wipe down the master cylinder with acetone or lacquer thinner and paint using black rustoleum. Let it dry for about a week and if brake fluid Jacks up the paint you can always touch it up.
I've seen spray graphite used for this. It ends up being a charcoal grey color and brake fluid doesn't seem to affect it. I've also seen it used on exhaust manifolds. The heat does seem to affect the finish some but it can be re-applied every year to keep it fresher looking. It can be sprayed on directly or sprayed onto a cloth and applied or sprayed into a container and applied with a brush. I have not done this yet myself, but I have a master cylinder to put on one of my '63s later this month and will be doing it to that one. A couple of my friends have done this and are happy with the results so far.
^^^^^This, except I've always used what I have and that's engine paint. PlastiKote (Dupli-Color) has a cast aluminum and cast iron colors. Never had one rust unless the paint bubbled from brake fluid, but this is So. Cal., no salt or major rain all the time.
Paint does like brake fluid or maybe it the other way around, regardless I don't paint them any more. True mine are usually chrome plated but when they are cast I use this Corvette manifold dressing. It is pretty amazing stuff and can be re-applied during a quick detailing. I use it on brake calipers and have even used it on AR TT's. Looks good on exhaust manifold as well
I have a new brake and also a new clutch master to install. Plan is to use a quality 2k black. But that's mainly because I have a qt or so of leftover Imron to use. If I didn't I'd probably buy a cheap urethane, That is an oxy*****! They stand a chance against a fluid spill if removed soon.
Whatever you decide, don't get too much paint on it. In fact if you can "stain" it that's better yet. Let it soak into the pores of the casting and it'll withstand a minor spill and give ya time to clean it before it tries to lift.
Thanks for all the replies, got some ideas I hadn’t thought about like the caliper paint and the manifold dressing. I’ll hit O’Reiley’s one day soon and check out their paint section. The engine paint also sounds promising. I painted my old one with Rustoleum, it has held up fairly well considering it didn’t get painted until it started rusting. As to the lid leaking, I haven’t seen one of these aftermarket ones that the lid didn’t leak a little. The gasket just doesn’t seem to be the quality of rubber like the OEM ones are.
I used caliper paint on mine. It won’t stand up to brake fluid forever, but it does pretty well if you wipe off a spill.
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