austin healey frogeyed Brake Master Cylinder
I have a 1959 austin healey frogeyed sprite i have converted it to front disk, i have changed the master cyl to a 3/4 bore,and blend the systems 5 times,   I PUSH ON THE BRAKE PEDAL, IT GOES ALL THE WAY TO THE FLOOR.,but once i pump the pedal 3 times i have good bakes,however when i leave it for 5min the pedal goes to the floor, their is no break fluid leaking anywhere.please can you help tyrone

Optional Information:
Pre-1981 frogeye 950cc

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