My Brake master cylinder seems to be leaking slowly. No signs of leaking from the outside so it must be leaking internally. What should I do?

 

mine was leaking right by the fire wall. fluid had leaked into the engine bay and the paint was peeling. so, i had to get a new one it was like $50 after the core charge. at advanced auto. thougt Id let you know incase it ends up being a similar problem.

 

I have a brand new Master cylinder for $60.
pm if you want.