what master cylinder or do I just need to change the residual valve in the one i have? The one i have is stock front disc and drum rears. Any help would be greatly appreactied.
rear disc conversion
- Thread starter bigblockmadness
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For this advice I talked to Ed Miller at www.flynbye.com and he recommended the stock master cylinder. I sent him a used proportion valve and he modified it to use with a 4 wheel disc swap. He charged me $35 I think. I imagine someone on here can tell you how to do the mod as it's supposed to be really simple.
Anyone?
Anyone?
+2 on the does anyone know what the mod is? I want to do this myself but don't want to have to deal with a adjustable prop valve! 
I put 4 wheel discs on a MCSS at work and we used a master cylinder from a '79 WS-6 Trans Am, since those had discs all around from the factory. Never got to drive or even finish the car, but it had good pedal!
rule of thumb is....You need a 1 1/8" bore master cylinder and you need to run 3/16" brake line to the rear discs. I have seen cars work without changing a thing though. The best bet is to browse www.mpbrakes.com especially the troubleshoting section. With 4 wheel disc you should no longer need an adjustable proportioning valve. However you should change you combination valve.....(the one bolted to the frame under the drivers side) to a disc/disc version. The factory one in a g-body is setup for disc/drum.
Email either Ed Miller at www.flynbye.com or Tobin at www.kore3.com Both are regulars on pro-touring.com among other boards. Either one or both can guide you to what you need. Ed modified my prop valve to work with disc/disc setup. The mod is supposed to be fairly simple needing to remove a valve internally. Disc and drum brakes require differant pressures and this valve regulates them. Without this valve, the front and rear disc get the same pressures. But just because this is a g-body prop valve, when you swap from drum to disc you are also changine the sizes on the front andrear brakes. That's why it's still recommended to run an adjustable rear valve. You can run either a modified prop valve *and* an adjustable or just the adjustable in solo. That way you can still have full pressure to the front and adjust the rear down to just below lockup simce the front does most of the braking and is usually larger in diameter.
If I'm not mistaken, even Baer uses the stock master. That's what Ed recommended I use but since I haven't got my setup installed I can only pass on his advice to me along to you. Or, you can email him on your particular setup as it may be differant than mine. I'll be running the 13" C5 front and the 12" LS1 rears...eventually...
If I'm not mistaken, even Baer uses the stock master. That's what Ed recommended I use but since I haven't got my setup installed I can only pass on his advice to me along to you. Or, you can email him on your particular setup as it may be differant than mine. I'll be running the 13" C5 front and the 12" LS1 rears...eventually...
I wouldn't suggest Flynbye. It took Ed over a month to get some rear brackets made for me to put on my 9" ford. One excuse after another. Then he was going to make front brackets for me. NEVER happened. The ones he did make for the 9" put the caliper so far off the rotor I had to re-work them myself anyway. It was a lot easier to make the front ones myself after getting yanked around by this guy. Touring classics was a big help in getting my project finished. Try Touring-classics.com. As far as the proportioning valve. I will use a rear adjustable. But I did see this and it looks ideal.
http://www.jegs.com/p/JEGS/JEGS-Adjusta ... 3/10002/-1
http://www.jegs.com/p/JEGS/JEGS-Adjusta ... 3/10002/-1
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