Master cylinder conversion

[V8 Bob]

Originally Posted by funrunr

V8 Bob, did you have clearance problems with the F250 MC in your 40? I used a 69 mustang in mine and had to cut the cover and weld flat. Otherwise is too tight to the floor and cannot remove the lid/cover.....

I had to make a slight "hump" in the new/larger M/C cover to clear, but it's not really noticeable under the carpet.

Originally Posted by scooder

....If the master cylinder bore is to small, is it possible that it will work "fine" with both circuits operating as they should, but in a one circuit fail, the master cylinder can't displace enough fluid to operate the one circuit now doing all the work. Irrespective of the ability to full stroke?.......

Martin, the two circuits are isolated, and only operate two brakes each. The 1" master is the most common size, and generally will work with most car/light truck/street/hot rod brake systems, but they do vary on total and primary/secondary displacement, or individual stroke, depending on intended application. However, checking each circuit for operation and pedal reserve during bleeding will show if there is a fluid displacement problem.
Generally, brake pedal force on factory vehicles is somewhat controlled by public feedback, but mostly DOT maximums allowed during required testing the vehicles have to adhere to, and is a good guide when building a custom system.