Technical Brake M/C bore experts, step in.....

I want a bit less pedal pressure needed to stop my 55 Chevy. WHAT say you experts to just how much (little) to reduce the bore on my the M/C? Assuming the discs front conversion includes the usual 1" M/C what size for the new bore fpr just a hair easier pedal effort without gaining too much more pedal trouble? THX

 

15/16", or 7/8".

 

Small changes make a quite large difference. Looking at the Wilwood website, using 1" as a baseline, 15/16" would be my choice, bit more pressure without too much added pedal travel, or indeed trouble!

Chris

 

going from 1" to 15/16" will reduce pedal effort by 12%.

going from 1" to 7/8" will reduce pedal effort by 24%

But...pedal travel will increase by the same amount! make sure there's enough travel

 

Groucho,
Might be a simpler solution.
Making another assumption , manual brakes??
Just move the push rod hole down 3/8 to 1/2 " ...
More leverage...
The 6 to 1 ratio is critical for non power brakes..

Dave

 

I agree with BJR. I have exp. with both and found a noticeable amount of feel in difference.

 

A 55 Chev has swing pedals, moving the push rod down will increase the effort needed to stop the car. It gives you LESS leverage, not more.

 

Several power brake conversion kits for the tri fives tell to redrill the push rod hole lower on the pedal.

 

That's to reduce leverage when adding power brakes to make them less sensitive.

 

I went down this rabbit hole with my 37. Before doing anything else, I’d recommend starting by documenting exactly what you have now. What pedal ratio, what m/c, what wheel cylinders and calipers, and the bore sizes on all of the cylinders in the system.

I ended up going from 1” to 7/8” and am happy with the results on mine, but that doesn’t mean that’s what is right for your car.

 

Thanks man, lots of good info here!