front disc conversion

[mopar jack]

did the big rotor and pin type caliper conversion years ago and the brakes are much better than the 10 inch drums I had before. However I can't lock the front rotors on a hard stop with a 15/16 master cylinder. Will it help with a bigger bore cylinder?

[shawge]

With everything else being the same (caliper piston diameter, pedal ratio, rotor diameter, amount of pressure applied to pedal, and distance the pedal moved), a MC with a large bore size will have a lower MC pressure than a smaller bore size.

[1 Wild R/T]

With everything else being the same (caliper piston diameter, pedal ratio, rotor diameter, amount of pressure applied to pedal, and distance the pedal moved), a MC with a large bore size will have a lower MC pressure than a smaller bore size.

Translation larger bore makes less pressure so it requires a higher pedal effort.... You either need a smaller M/C bore or a booster....

[mopar jack]

I think a larger bore will make more pressure but take a more effort on the pedal to push it. I had a larger bore and the pedal was harder to push but  I could not lock the front rotors. The small bore I have now is very soft to apply but also travels further to the floor.

[shawge]

Did you have power drums before?  Is it power or manual now?  With a 15/16 bore, I assume it's a manual setup now   

[mopar jack]

It's a manual set up. started as a 318 barracuda with 10 inch drums. Upgraded rotors to C body and stock pin calipers, installed a factory  proportioning/ metering valve and a rear adjustable prop valve. Car stops much better than stock but I can't lock the front rotors.