Brake Line and Proportioning Valve

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Brake Line and Proportioning Valve

Postby Bacchus » Sun Nov 26, 2006 11:44 pm

Well, I was tinkering around on my car this weekend and was tallying a list of "things to do to at least drive it around the block." One of the issues I need some help on. I installed a new stainless steel brake line from the firewall to the rearend from Inline Tube. Very nice piece of work, by the way. I then was going to plumb it into an aftermarket prop valve. I'm running 11" Impala drum brakes on the Don Hardy 12-bolt rearend and want some adjustability. However, the size of the rear tube and it's retaining nut is significantly larger than the inlet to the Wildwood prop valve. I don't have it in front of me, but it's much bigger. Too big to just use a single downsized adapter. It would require several. What have other people done? Are there different size aftermarket prop valves that I should be looking at?
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Postby v8astregt » Mon Nov 27, 2006 12:18 am

Where'd you get your proportioning valve?

I too have a Wilwood, but it had proper fittings to adapt it. Quite a size difference, but it was done in one fitting at least. I know I bought more fittings like that at probably Ace Hardware, or some store like that.
75 Pontiac Astre GT: 406SBC/TH350, roll bar, S10 goodies, down to 11.47 so far, more to come later.
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Postby Bacchus » Sat Dec 02, 2006 6:09 pm

It's a wildwood. The end on the rear brake line appears to be a 7/16" NPT, and the largest I can find is a 3/8" to 1/8" adapter. I can't find anything in 7/16".
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Postby cosvega76 » Sun Dec 03, 2006 8:03 am

Brian,

Are you sure it's NPT? If it is the end of the tube, and has the inverted flare on the end, I would think it's 9/16-18 or 1/2-20. These are common brake thread sizes, especially in master cylinder and rear brake line applications.

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Postby Bacchus » Sun Dec 03, 2006 11:56 am

Honestly Chuck, I haven't gotten out to measure it, just grabbed a few fittings that I knew the size on and they don't fit. It is definitely MUCH larger than the input to the Wildwood. I'm guessing you are right on the 1/2 or 9/16. How do I get that down to the input size of the prop valve? I should know this, but don't.
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Postby cosvega76 » Sun Dec 03, 2006 6:38 pm

I believe Weatherhead makes adapter fittings from 1/2-20 and 9/16-18 inverted flare to 1/8NPT. At worst, you would need 2 adapters to do the job.

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Postby Bacchus » Sun Dec 03, 2006 6:46 pm

Any idea where to buy them locally? I'm surprised no one else with an aftermarket prop valve hasn't run into this problem.
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Postby cosvega76 » Sun Dec 03, 2006 11:14 pm

NAPA parts stores usually carry Weatherhead.

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