<VV> Brake Master Cylinder Question

[Jay Pitchford]

The master cylinder in my '65 Corsa convertible appears to be low on
fluid. I've purchased Valvoline synthetic DOT 3-4 brake fluid to add
some. My question is, do I add the fluid directly into the rubber cup
that's located inside the master cylinder, or do I lift it out and add
underneath? How much should fluid be in the master cylinder? Do I fill
it to the top?

Jay Pitchford