Master Cylinder question

Ross Wooldridge

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Hey all,

Regarding 66-68 C body cars - while I know that a Bendix dual diaphragm disc brake booster is supposed to be a semi gloss black (and KH drum boosters are cad plated), what colour is a dual res disc/drum master cylinder supposed to be? Were they painted at all? It's my thoughts that they were black with a cad plated lid and bale, but of course one only sees natural unpainted ones, usually rusted to crap...

The reason I ask is that I am considering having mine powdercoated, since any paint I've ever used on a master cylinder looks like shyte as soon as you go to check the fluid level. Powdercoat has improved a lot, and there are some great matt or semi finishes, including a cast grey for manifolds that are claimed to be impervious to brake fluid.

Thoughts?
 

MrMoparCHP

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All Black, I have a period picture (1969) showing this I can get in a couple hours.
2017-03-20_023.jpg



Alan
 

PH27L7

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They were very haphazardly painted semigloss black. Pics below show my original 1967 M/C prior to having it sleeved, you can see the remnants of the black paint. Last pic shows it rebuilt with a NOS cover. Its incorrect in that I painted it in chem-resistant cast iron. Booster shown is a '68 but is correct color. The '69 uses a different M/C & the one shown in the above pic is aftermarket.
master cyl 3.jpg
master cyl 4.jpg
MC rebuilt.JPG
 

bigmoparjeff

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I suspect that the boosters were supplied to Chrysler with the master cylinder already installed and that the painted units were likely painted as a complete assembly, which would explain the painted cover and hasp. The plated boosters likely had bare master cylinders with a plated cover.

Jeff
 

MrMoparCHP

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Here is a 1969 picture of a 1969 CHP Polara,
0901 - Overflow.jpg

and a picture of a somewhat original 68 CHP Polara taken a few years ago.
Dan's-06.jpg



Alan
 

Ross Wooldridge

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I must say I prefer the gresh look of the natural finish along with a cad lid, so now I'm torn as to which choice.

Either way I go, I'll be considering powder coating as the medium - what do people here know of its durability when exposed to brake fluid?
 

bigmoparjeff

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Normally, I would suggest that you switch over to silicone fluid to completely eliminate the issue with damaged paint, but right now I'm battling a lousy, soft brake pedal on a car that I switched over to silicone. I've had good luck with silicone fluid for the last 20 years till this particular car. I've run a half gallon of fluid through this thing, using various bleeding methods, and still can't get an acceptable pedal. I'll be heading up to the shop shortly to change it over to conventional fluid to see if that makes any difference. A friend of mine had a similar issue with a car that just wouldn't bleed properly and had to give up on the silicone.

Jeff
 

CudaChick1968

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Cast iron coats beautifully (all I have on my phone is a pair of flashy custom candy coated calipers but you get the idea).
FB_IMG_1606525159441.jpg


If the job is well done it will last a lifetime. Be sure to clean any spills on the sides and bottom of your master cylinder promptly if you aren't using Dot 5; it won't take it down to bare metal but could dull a shiny finish a bit if left to soak in. Of course all threads should be plugged and the interior portion should stay bare.
 
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