Did you need to change to a disc / disc proportioning valve when you added the rear disc brakes to your car? What about a different master cylinder, did you need that?
No I am running the stock Prop valve and stock master cylinder. But will be adding Wilwood front disc and Wilwood master cylinder soon
Good to know. I guess I will install the rear kit and try it with the stock proportioning valve first and see how it feels. Thanks guys ............
Perfect! My plan was to do this until I read the directions with my kit and they said it should be changed, which is why I wanted some feedback what others have done. Now that I'm thinking this over it would seem to me that the drum / drum stock valve should be a winner with disc / disc and you guy's have all confirmed this. THANKS AGAIN all you guys ............
The drum/drum master will have a smaller reservoir. Might be a problem when trying to fill 4 calipers.
also, you should take into consideration that the master cylinder will have a residual pressure valve built in. they are not made for disc brake systems, as the remaining pressure is too high. the inline valves for street rods are 10lbs for drums, 2lbs for discs. so you should shop around for a 4 disc master - i used a 90s ranger unit as suggested somewhere on here. the "proportioning valve" is not a valve, but a mere distribution block and will work fine. only the later units made for disc/drum systems have a valve built in.
While that is true, drum / drum stock valve doesn't have the separate proportional valve spring inside like the disc / drum valve does - 99% of anyone reading this knew I was referring to the stock pressure valve. Proportioning valve is used generically, like Kleenex for a tissue. Sorry if I was sounding misleading to anyone ............. Yes, I need to see what I have on the shelf. I know I have some full size Ford disc / drum ones. My instruction sheet with the kit says the bore should be at least 1.125 but it doesn't say anything about reservoir size.
Okay, I wasn't sure if you knew that or not. You definitely need the correct master cylinder (bore size for discs is sometimes different from drum). As far as prop-valves; the need for one would depend on whether or not there is excessive rear-wheel lock-up. Cars with "big 'n' little" tire combinations often don't need a prop-valve. Personally, I'd try it without, and if needed, install an adjustable prop-valve.
Yes, will try the stock valve and see what happens. And the rear tires are bigger so that should help. Looking at the Scott Drake 4 wheel disc master - Summit has it for around $90 with free shipping.
I used a master for 74 maverick and a wilwood adjustable purportioning valve. The 74 uses a 15/16 bore size. I use this on a manual brake set up with 13" disc from a 96-04 cobra up front and an explorer disc in the rear. I've put less than 40 miles on it before tearing the car apart for efi and some steering upgrades. They felt good even with a leak I found in the right rear. I heard the 02ish v6 mustang uses an aluminum master with a similar size bore.
