The Stovebolt Site Forums The Shop Area Driveline Master cylinder question 1inch vs 1 1/8 inch

I have a 1941 1 Ton. The front brakes have been changed to disc using CCP disc adapter kit.
The rear brakes are drum but a more modern version from a rear end swap.

I think I have a 1 inch bore dual chamber master cylinder mounted in front of a 7inch twin chamber power brake booster

Right now it stops but the pedal appears to engage very close to the floor. I would like a little more room between the pedal and the floor so more pressure can be applied before the pedal hits the floor.

My question is:

If I go to a 1 1/8inch master cylinder will the brakes engage sooner. Logic tells me that that by moving more fluid in a larger chamber will engage the brakes sooner so there would be less pedal travel.

Am I correct? Any suggestions are greatly appreciated.

Hy Murraydave, your logic is impeccable, yes a larger bore master cylinder will cause the brakes to react quicker. Your disc brakes automatically adjust, just make sure your rear brakes are kept adjusted up as well. Your pedal to master cylinder clearance is very important also, you don't want too much clearance, which results in pedal movement with no braking action, hope that helps.

As bore size increases so does pedal effort. 1" to 1.125" will require 36% more pedal pressure but if this is too much a bigger booster would offset the increased effort.