TR6 clutch hydraulics question

[richard bacon <rbacon@netcom.ca>]

Greetings Listers:
I have rebuilt both the master and the slave clutch cylinders, replaced
the plastic hydraulic line and bled the system thouroughly (three times)
with alternate methods.
I still loose clutch action after 15 minutes of driving.
Master cylinder was a little pitted internally and the Bentleys cautions
that any pitting will render the cylinder useless: anybody had
experience with this problem?
should I replace both cylinders ? (!!!!!$$$$$).

Any input would be of help

rick
72 TR6