67Rocket

We all know a power brake booster reduces the amount of effort required to depress the brake pedal but does the booster actually change the pressure in the brake line itself? Thanks

oldcutlass

No, the booster just reduces pedal effort, the MC controls line pressure.

joe_padavano

The pressure in the brake line is a function of how hard you push on the back of the M/C piston. The M/C is simply a piston of a given number of square inches. Divide this area into the pounds of force applied on the back of the piston (by either the pedal directly or the booster) and you get PSI. Since the area of the M/C piston is fixed for a given M/C, obviously the harder you push, the higher the PSI out the line. The booster CAN increase the force applied to the back of the piston, depending on a whole lot of variables (pedal force, pedal ratio, etc). The reality is that the booster is more often used to reduce required pedal force for a given line pressure, but if the pedal pressure remains the same, the booster makes line pressure go up.

Firewalker

http://www.classicperform.com/PDFs/B...ssureChart.pdf