Disc BRAKE issuE- loosing pressure BUT WHERE>?

Talking Disc BRAKE issuE- loosing pressure BUT WHERE>?

1968 barracuda front disc brake conversion 73+ Abody set up.
power steering
brake booster with DUAL compartments rear drum front disc.

front reservoir loosing oil somewhere, have to refill every 3 weeks/month - traced the line from booster/ reservoir to lines to discs and found no leak....

whats my issue?

bad booster? bad reservoir? :burnout::burnout::burnout::burnout::burnout: :banghead: