Questions about plumbing a brake system

66coupe351

Founding Member
Aug 24, 2001
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Los Angeles, CA
I'm in the middle of replacing most of my stock '66 GT brake system and have a few questions I was hoping someone could help with. I'm keeping the front disk/rear drum setup, but replacing most of the parts.

My main question is related to adding a combination valve(metering and proportioning) into the system. Most of the brake line fittings are 3/16"(I think), but the two inputs on the combination valve are slightly bigger(1/4" ?) than that, and the rear output fitting is a little bigger than the inputs(5/16" ?). This has me doing things like connecting a 3/16" output from the MC to a 1/4" input on the combination valve. I assume I use a standard size brake line for this, but then would I use a larger fitting on the comb. valve side of the brake line or maybe a standard fitting connected to a step-up fitting connected to the comb. valve? After writing that all out I think I could probably go either way, but would still like to hear from people who have done it.

A few other side questions:
Know any good places to buy straight lengths of stainless steel brake line? How about stainless fittings?

It appears the only valving the car originally had was a proportioning valve in the rear line. I plan on using a metering valve in the front and a proportioning and residual valve in the rear. I think this a good way to go, but... From you experience is this the correct thing to do? Is it going to be a nice improvement in home the brake system works?
 
ditch the combo valve. Just get a T fitting to split the main line for the front brakes, and install an adjustable prop. valve in the line going to the rear brakes. The combo valve (or distribution block) is a pain to plumb, plus they're messy/jumbled looking, and (as you've found) sometimes require some funky and hard to find adapters.
 
Well, found that Jeg's has lengths of Stainless Steel tubing pre-flared with ends. They don't seem to have any size adapters, though.

So, maybe the comb. valve isn't worth it? I was hoping it would help to modernize the brake system. Anyone out there add a comb. valve to their brake system or have any opinions on if it is worth it?
 
Just dont forget, if you install a manual prop valve, you are going to have to test it and set it correctly, and mark it. Its not a install-and-forget like a stock valve would be, at least the first time out.