70 Duster power to manual brake conversion

So I found the problem. One of the outboard pistons on the driver's side caliper is leaking. And it has probably 10 miles on it since it was installed. And it never had a good pedal. so it's been doing that since install. Of course, I've been off and on trying to fix this for 2 years, so yeah, no warranty. And I don't see any calipers I can just purchase on ssbc's site. Great. Guess I'll call them, or find out how to rebuild calipers.