Master cyl question....

[Black63]

Had this on the Brakes, suspension forum but got nowhere so I figured I'd try here!!!!

Hey guys....doing some parts ordering for the "Rust Revival" thread 63 330 and after doing a quick search of the site I'm still confused on just what master cyl I'll be needing.

I'm using 12", pin style Calipers/discs from a 78 Charger and a 67 Plymouth rear axle. (10" drums and 7/8th wheel cylinders I believe)

I was figuring on staying with manual brakes, but If power is what I must use I'll go that route...although that will require some complicated sourcing of parts.

What master cylinder is going to work and give normal pedal stiffness?
My wife will be driving it at times so I don't want a rock hard pedal!!!

Thanks!

 

[Meep-Meep]

I think a 1" MC bore might be a good place to start. For power assist I believe a 1-1/16" MC is used.

 

[Jonnyuma]

For an unassisted, no boost manual brake setup you want a smaller bore master cylinder, like 7/8"(I've seen as small as 3/4"). The small bore moves more fluid with less effort and pedal travel. Theres lots of small-bore MCs available from the aftermarket. If you're wanting a specific OEM application, I'm afraid I'm no help there, I haven't owned a vehicle with unboosted brakes since I sold my '64. My gut feeling is that for a small bore dual pot MC, your gonna have to go aftermarket. Wilwood makes a nice one that's not too flashy (not billet street-rod geezer parts) or expensive. The pro-touring guys and vintage racers have helped us out in the unassisted-but-safe brake and steering departments by paying big bucks so companies could develop these kinds of parts and offer them to the rest of us at reasonable prices. Hope this helps some.

 

[Meep-Meep]

Thinking about it I'm sure I have a 1" bore MC with the late A body single piston brakes and rear drums. Seems to work fine but as mentioned a smaller bore will make for less effort but a longer travel.

 

[Revhendo]

Check out a stock manual master for a 73-76 Dart. Should be about the right size.

Oh, and,
The larger the bore, the less the travel and the higher the effort.
The smaller the bore, the more the travel and the lower the effort.
It's a Pascal's law thing.

 

[Black63]

Thanks guys! Really appreciate the info.

I'm using the big brakes from a 78 Charger and I'm a tiny bit concerned that the Dart master might be a bit small IF the caliper pistons are larger on the Charger brakes.
I actually have a Dart disc brake master to use as a core for the rebuilt one I'll buy.

Does anyone know if the calipers on the Charger have the same size pistons as on the Dart...or does it really matter in this case???