Posted by Johnd [71.246.89.63] on Monday, July 21, 2014 at 18:29:15 :
In Reply to: Re: Brake pedal problem posted by ern in ca [50.173.35.78] on Sunday, July 20, 2014 at 23:44:22 :
See if you have mechanical slop in the pedal linkage.
Move the pedal with your hand to the full up position. Slowly move the pedal down while watching the piston in the master cylinder. (You will need to peel back the boot to see the piston). Even as small as a 1/4 inch of play between the pedal and the piston pushrod could relate to several wasted inches of pedal travel that does absolutely nothing. Some of these rods are adjustable.
Also make sure the piston in the master cylinder is being pushed forward fully by the spring inside the MC. If not, it will trap air forever inside the MC.
Good luck, tell us what you find.