master cylinder 4 discs, 73 dart front / mustang2 rear, manual

[Buschi340]

Guys,

I converted my rear brakes from drums to ford mustang 2 disc Brakes. In front I swapped to 73up discs ( had already 72 discs before).

As i was bleeding the brakes I felt the master cylinder might not carry enough fluid in his cylinder per stroke for the rear brakes since it is designed for drum brakes. Can this be? The pedal has a pressure Point almost down at the floor.
Do I need a master cylinder with more stroke? Using an adjustable pushrod.
Currently I have a diameter of 15/16 ( not sure, it is still the original power m/c from my 72 disc/drum car ) which brakes great and I don’t want to go much bigger in Piston diameter because I don’t have power brakes.

I found some master at Mancini MRE3360 (bore 1.031", stroke 1.55 ) & MRE3459 ( 1.125", no stroke given - too big???)

And the wilwood 260-4894 (bore 1.063" , stroke 1.35" )

I think less Diameter for good pressure and more strok for more fluid for the rear calipers?

 

[70Duster440]

I was talking to Cass (Doctor Diff) last week about this since my son is doing a rear disc brake conversion on a Ford 9". We already had one of the aluminum MC's he sells (essentially same as Mancini unit) and he said it would work fine without any mention of stroke or volume. He said they're essentially a 4 wheel disc brake MC (don't have the residual valves that disc/drum MC's might have). I don't know about the Mustang II calipers, but the GM metric calipers used in the conversions will need a proportioning valve to get the correct brake bias.

I don't think you'd like 1.125" - too big, too much leg effort for manual brake, even it it could deliver the fluid.
I run a 1.03" on my Duster. (1-1/32"), stock pushrod.
My son will be using the .9375" (15/16") we had sitting here.

http://www.doctordiff.com/aluminum-master-cylinder-kit.html

 

[Buschi340]

in my eyes i Need most stroke i can get with less Diameter. In 1.063" dia wilwood offers 1.35" stroke. Mancini has one with 1.55" stroke. Hope i don't floor the pedal with that much stroke.