I am trying to reduce brake pedal travel on my 2011 Mustang track day car after installing 6 piston "Bullitt" Brembo front calipers. During my search for solutions I came upon a post showing a .312" rubber washer in between the brake booster fork rod and the master cylinder actuation rod. The post was on a Mustang forum and supposedly the booster shown came off a Ford Mustang. The idea of replacing the .312' Rubber with delrin was too good to pass up. I purchased an S197 booster on E-bay and took it apart and removed the valve assembly (shown without the seal).