Need help with master cylinder theory/operation, please.

[YerDugliness]

Originally Posted by bobcowan

This page will give you an excellent explanation of how it all works together: Brake Article© by Dean Oshiro

I've tried your link multiple times, also copied the URL and pasted it into my browser window, can't get it to connect...even added an "l" at the end believing it was an html attachment..sure would like to read it, though, Bob!

I've had the car out to a rod builder who has a reputation for doing the best brake work in the area, and after looking at my setup his first bit of advice was to get a "Corvette" type master cylinder. I see the difference between the one I have and the Corvette type, the 'Vette type has two equal sized reservoirs in the master cylinder while mine has a large reservoir closest to the firewall and a smaller reservoir at the front of the master cylinder. Since this is a manual brake system, it makes sense to me that the reservoirs (and, hopefully by extension, the volume of fluid moved when the brakes are pressed) would need to be equal.

I don't think there's any way to adjust the length of travel of the piston. Since I don't know much about brake theory, I'm at a loss for what to do now. Logic tells me that in order to more effectively clamp the disc pads against the disc, more volume of fluid needs to be moved when the brake pedal is pressed. If that is right, I have found a 1 1/8" bore 'Vette style MC at Speedway Motors, see this:

Power/Manual Master Cylinder, 1-1/8 Inch Bore - Speedway Motors, America's Oldest Speed Shop

However, if a smaller bore is better (keeping in mind that there is no way for me to adjust the "leverage" by increasing the stroke of the piston), Speedway also offers this 1" bore model:

Power/Manual Master Cylinder, 1 Inch Bore - Speedway Motors, America's Oldest Speed Shop

I think the MC needs to be replaced, regardless....I think it is leaking into the footbox from where the piston rod enters the MC and replacement of the carpeting is waiting to get that issue resolved.

These are both said to be appropriate for both manual and power brakes, and mine are going to have to remain manual, so I guess my only confusion is which bore to buy.

Would the 1" bore offer greater clamping pressure and therefore better braking, or do I need to get the larger 1 1/8" bore MC?

Either way, a proportioning valve will be sourced and installed into the brake line leading to the rear of the vehicle....I don't want the car swapping ends if I put the brakes on, and on wet roads this lightweight car with 11" wide rear tires hydroplanes VERY easily, so I'm wary of that issue!

So confused.........so that I don't understand this, I'm usually very competent regarding mechanical issues and this one is evading understanding.

Thanks, guys, for whatever help you can give me!!!

Cheers!

Dugly