Slacken both nuts with, let the pedal settle in up position screw the nut furthest away from the cylinder till it is nearly touching pedal assembly bring the other nut to similiar position, try your brakes,the ball end on the rod that sits in the cup of the master cylinder should not be in contact with the cup of master cylinder hence a small bit of freeplay to allow the master piston to come back to rest when you take your foot off the brake pedal.