Dual disc MC & proportioning valve question

Hey guys, I am getting ready to put in my 44 front and am doing the rear disc conversion at teh same time. So, I am upgrading my MC to a 68-9 vette cylinder. My question is really about the proportioning valve. I have had it explained to me this way.
"There are two ways to correctly accomplish proportioning with a dual disc set up. The first is to use a combination valve designed for this purpose such as one from a rubicon. The second is to get (2) 2 lb residual valves, a tee fitting, and a willwood adjustable proportioning valve. You place one of the residual valves after the mc on each line. Then for the front you place a tee fitting to split the line to each caliper. For the rear you place the adjustable proportioning valve and tune it so the fronts lock up just before the rears. It is mearly preference which way you choose. The residual valves keep you from having to move the pedal as far before the brakes apply, and keep the calipers full of fluid. A combination valve already contains them."
So I am curious which one you all would recommend and any other thouhgts you may have on all of this. Thanks in advance.
josh

Back when I was racing hillclimbs and autocrosses, I built one of my cars from a super "plain vanilla" V8 Javelin that started life with 4 wheel drum brakes and no power booster. I converted to later model AMC discs in front and added a booster. What I found was that drum brakes used a check valve to keep the shoes from retracting too far, and when I put discs on the front I had to remove that check valve or the discs wouldn't release all the way. I have never heard of a residual valve in connection with disc brakes, and don't know what function it would serve.

As to the proportioning valve, that's what it's for -- to establish a proportion between the front and the rear. I see no reason to use two. You WANT full braking on the front end. The reason to maybe reduce the braking in the rear is that if the rear brakes are good enough, under hard braking when the weight shifts forward the rears will lock up before the fronts, causing a spin-out. If I were doing what you're doing, I would skip the residual valves and run one Wilwood proportioning valve, in the circuit for the rear wheels.

Keep it simple.

Josh, SeanP just brought this up over on Pirate, and I believe he said the vette MC wouldn't fit or something. There's been talk of using a '98 Dodge 3500 MC and that it works well. A couple of TJ guys have done it with success. Something to look into anyway.

Ary

Safari Ary said:

Josh, SeanP just brought this up over on Pirate, and I believe he said the vette MC wouldn't fit or something. There's been talk of using a '98 Dodge 3500 MC and that it works well. A couple of TJ guys have done it with success. Something to look into anyway.

Ary

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Wouldn't fit because of the shock hoops he bent up. It'll fit, there's 3 guys here running them Hulk can go look at if he needs to.

I think you're over thinking this Josh. Corvette Master bolted and sealed to your stock booster. T the front lines together and run them to the master. Put the proportioning valve in the rear line and you're done. The rest is just dialing it in.

korda said:

I think you're over thinking this Josh. Corvette Master bolted and sealed to your stock booster. T the front lines together and run them to the master. Put the proportioning valve in the rear line and you're done. The rest is just dialing it in.

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Youre probably right korda. Thanks for the good point. I am going to get the MC and hopefully all teh adapter lines from Ben today. I might have you or Coty come over when this part goes in, you have more know-how on this than me. :worship:
Thanks for straightening me out...
josh