"Limp Arbor" wrote in message
...

As was already said you most likely have a leak or a bad master
cylinder. The seals in a master cylinder can go without showing a
leak. Top off the fluid and *gently* pump the pedal to see if you get
improvement.

A 'bypass' leak of the internal cups in the MC will cause the described
symptoms. Instead of pressurizing the lines/cylinders it will simply cause
the fluid to re-circulate within the MC.