My 53 had a hydrovac setup similar to the one you're describing. Instead of re-building it, we decided to upgrade to a dual master cylinder power brake system. The donor cylinder and booster came off of an 81 1-ton Chevy Suburban. We wound up fabricating a bracket and mounting it on the frame in the same general location the old master cylinder was. The only real issue was that we had to make an access panel in the floor to get to the cylinder to fill it with fluid and the inlet sizes for the brake lines on one side of the cylinder were different than the other. However, after we got those few minor kinks out, it brakes extremely well and we're happy with it. If you'd like any pictures of the set up on my truck, let me know through private message or e-mail and I'll be happy to send them to you. Good luck!

When at first you don't succeed, get a larger hammer.

1953 Chevrolet 6400 Flatbed