I replaced all my wheel cylinders, lines and master on my 68 40. I ordered them from man-a-fre. I had a problem with the master right away (leaking). To man-a-fre's credit, they sent me a rebuild kit free of charge 1 year after the install. I replaced the inards and was good to go for a while...
The cylinders where el cheapo's. The adjusting screws were wrong (backwards). Some had rubber gaskets on two sides others on one...
While all of this was going on, brake fluid was dripping from various places all over my frame and floorboards. Brake fluid is a great paint remover by the way.
So, I replaced all (master and wheel cylinders) with Toyota parts (thanks cDan!) Now I have zero brake issues and they will be good to go for a long time.
I recommend using Toyota parts. A little more pricey but you get what you pay for.