Master is cheap and well worth it. Just follow the bleeding procedure and while you are at it, flush until all the fluid is clear from the wheel cylinders and fill with fresh fluid. Check your wheel cylinders for seepage as well, old rubber seals like to leak after first re-use.
If your master cylinder is the original, don't turn it in as a core.
Vikki 1969 Goldenrod Yellow / black 400 convertible numbers matching