Please help me with my brake lines...

[Hazieview]

Well I ended up buying a willwood proportioning valve.

I'm having trouble mating up my stock brake lines with this aftermarket proportioning valve. The outlet of the stock proportioning valve going to the rear brake lines is a 1/4" line with a 9/16" fitting.

The Willwood proportioning valves are 3/8-24 with an SAE inverted flare for standard 3/16" (-3) brake line.

What I need is a 3/8-24 fitting that fits a 1/4" brake line or is there would it be easy to get a new brake line that hooks to the union going to the rear brake line?

Any help you can give me would be greatly appreciated. I'm stumped...

[wraprail]

Your rear brake line has a union fitting about half way down on the right side inside the frame rail. Install a 3/8-24 to 7/16 (not sure about the thread here) adapter here and replace the front half of this line with 3/16 line to your new prop valve. Do you still have rear drum brakes?

[Hazieview]

That is exactly what I was thinking... My rear brakes are no longer drums. I converted them to disk brakes. I was just wondering if it would be bad to feed the 3/16" (front brake line) into a 1/4" (rear brake line)? What do you think?

[wraprail]

I think I would replace the whole rear brake line with 3/16. I don't know why they used 1/4 on the rear. I am currently doing my brakes complete system using the same wilwood prop valve and using 3/16 throughout. I have stock front calipers, ford floating rear calipers and corvette or Chrysler manual master. AN-4 braided hoses
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[wraprail]

One comment on the Wilwood combo valve, it does not have a metering valve which the factory valve has. My last custom brake system I built didn't either and i had trouble with rear brake locking under hard braking. Actually turned me around on the freeway once. To cure this I used a LBS from Stewert (now made by DPI). I'm using this valve again.
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[Hazieview]

Thanks for the info. Just curious about a couple of things. The Willwood proportioning valve is adjustable. Couldn't you just adjust the flow to the rear brakes?

Also, why did you choose -4 AN instead of -3? I thought the -3 was the closest to the stock 3/16 lines?

[wraprail]

I used AN-4 cuz thats what I had. We used -4 on our circle track cars and I have a bunch used and left over fittings and hoses. If I was buying new I would go -3 for sure.
The metering valve works on the front brakes only and holds or delays pressure IIRC. It must be somewhat important otherwise the OE's would not have included it. On the other hand I must not be that important otherwise Wilwood would have included it in their combo valve. I used an adjustable proportioning valve before and had some rear lock up. The LBS cured all of it. Never locked the rear tires again.

I should point out that I have manual brakes and a manual 5 speed (and now 6 speed) transmission. I tend to drive this setup alot differently than I drive an automatic with power brakes. Braking while downshifting for example, is something you don't do with an automatic and I do on every off ramp and stop sign. So the rear lock up problems I had someone driving "normal" would never see.