'65 volvo 122s master cylinder problem?

Hi,

I recently purchased a '65 Volvo 122s. Runs great, but when I hit the brakes it would pull to the left. I popped off the wheels and I found that the right disk was rusty, while the left was shiny.

Tracked down the problem to a clogged brake hose. They weren't available, but I had them custom made. I replaced bot the front ones.

Unfortunately, the bleeder valves were sheared off. Getting them out is obviously non-trivial, but I was able to get a pair of replacement calipers from a local Volvo salvage yard.

Having replaced those I find that I have a new problem! (Frustrated.) Now the brake pedal sinks to the floor. I don't see a leak anywhere, nor does the level drop.

Did I somehow destroy the master cylinder when I repaired the rest?

Please help.

Thanks,
Keith

P.S. On the assumption that the problem is that the brake system like the old thick crappy brake fluid better, and replacing it killed the master cylinder... Is there something that can be added to brake fluid to thicken (/age) it?

I know this idea is a hack, but I doubt that a rebuild kit for the master cylinder of this car can be purchased anywhere and I hardly plan on driving it down a mountain.

Ideas?