I don't think any paint handles much spillage but I used VHT satin epoxy spray on mine. Figured epoxy would be a little tougher

 

Mike, that is a pet peeve of mine. I have seen soooo many nice cars with a rusty MC. I used Por-15 on mine.

 

Hmmm. I actually have some black POR-15 on my work bench, an unopen pint of the stuff. David, how long has your master been painted and has it held up with use?

 

I use slicone fluid in all my old cars, which doesn't destroy paint if spilled... AND it isn't hygroscopic (doesn't attract moisture from air and collect water in the brake cylinders/lines)...

 

I used the POR-15 exhaust manifold gray paint on mine, it looks like cast iron and is holding up nicely. I haven't spilled brake fluid on it yet, so can't answer about that.

 

This is what I use also. Brake fluid will hurt it but it’s super easy to touch up.

 

POR is pretty tuff stuff. I would think that it has staying power on a MC. But like any spill, wipe it up right away and test on an inconspicuous spot Besides how many times do we take the top off over the years.
I cleaned mine and just "cleared" it for the off the assembly line natural look.

 

Pi

c of my naked MC

 

I'll probably use DOT 5 Silicon fluid in my '57, with all new drum brake cylinders and lines, and a rebuilt Treadlevac master cylinder.
Since I don't have antilock brakes, I won't have to worry about that incompatibility.

I don't understand the two underlined phrases.

From DOT 3 vs DOT 4 vs DOT 5: What are The Differences? | Rx Mechanic
A DOT 5 brake fluid does not absorb moisture, and it does not cause any harm to painted surfaces. This brake fluid acts as a weather barrier to the brake system. DOT 5 can replace DOT 3 and DOT 4, but you should not mix it with any of the other brake fluids. Silicon-based brake systems are more difficult to bleed.

However, once they bleed, a brake system filled with DOT 5 brake fluid will resist rust better and also stay for a longer period than other formulations. This brake fluid is also lighter in cold temperatures. It weighs around 900 at 40 F. The viscosity of DOT 5 is much more stable in extreme temperatures. It is ideal and can be used in most external boots, and it is also compatible with all components of standard brakes.

DOT 5 brake fluids also have some drawbacks. It expands significantly when hot and the additives can vaporize at moderate temperatures, thus increasing the spongy feel. This fluid is incompatible with systems that have used glycol-based fluids before unless you flash it and have the seal replaced. It is also not compatible with anti-lock brakes wince the silicone fluids are more viscous. Unlike glycol fluids that start compressing when they near their boiling points, silicone brake fluids begin to compress when it gets to 300-350 degrees Fahrenheit.

 

I used the grey on mine several yrs ago to stop rust, then I sprayed rattle can enamel close to the body color to make it look better. Sometimes I have to touch-up the blue, but the Por-15 is still there.

 

I used Eastwood Brake Gray rattle can... "Brake fluid resistant"
I've got most of a can left.
You can a take a "quick" lunch break and go to Eastwood's .

 

Virtually every high end build that comes through my shop is running DOT 5. I followed suit and switched over to DOT 5 with my panel truck and again with project Snobad. So nice to not have to worry about spillage or leakage on any painted surfaces. Only downside I can see is that if you're switching over from DOT 3, you have to flush out the entire system, as they are not compatible. Dave

 

Get an aluminum master cylinder that doesn't need paint and won't stain.

 

I just sprayed a brand new one with clear and we'll see how it holds up. It looks really good right now...

 

Don't laugh at me but I rub anti-seize on my cast parts. Exhaust manifolds, master cylinder and original steering box. It makes them look new and touch up once a year if needed. You don't glob it on just rub it really good into the part with a rag. Yes it will leave a little mark (like you rubbed a pencil on your finger) if you touch it but how often are you touching those parts anyway?
Todd

 

I have heard that clear coating after painting lasts longer

 

For a simple solution you can also use for other under hood applications, I've had good results with Dupli-Color Engine Ceramic spray bombs. As a rattle can product it costs slightly more than Krylon, but there's no comparison in performance. It's all I use for such applications, including master cylinders. Have not used the clear in that application, but I probably will on my current project. Not a high-heat coating for exhaust manifolds and headers (they say it's okay to 500 degrees), but it'll survive under the hood on everything else.

Engine Enamel with Ceramic™ – Duplicolor

Detailed Product Information for Dupli-Color® Engine Enamel with Ceramic™: get full product description and specifications, check out How-To Videos (as applicable) and see how other automotive enthusiasts have used Engine Enamel with Ceramic™ on their vehicles

www.duplicolor.com

 

Used POR-15.

 

On my first dual master I painted with clear coat made for brake calipers... worked great until the fall and the condensation found the 2 little drips i had let happen at some point and had two little rust streaks down the side. My current MC was not painted and is starting to show some discoloration.. will try a few things to remove the rust and help protect the cast iron. maybe just wipe it down every now and then to avoid having to pull it off the firewall and try to clean it before painting.

 

Mike, I disassemble the master cylinder and have the casting clear powder coated. One time and done

 

I used silver Rust Bullet on mine.

 

Ran across this today while going through my files.