My Dad is in his mid 80's and while still going, he too admits to leaks now & then and has likely not been used as hard as that old B!
I did much the same as you're describing with a '39 B a few years back. Almost in the aggravatingly unique category isn't it!
Worked for a week disassembling just the right brake assembly! I was just glad I never broke any of it getting it apart!
Overall it worked real nice when finished! Easy start. Easy to run. Took it for a drive one day.
Three Amish boys in a spring wagon pulled out of their drive onto the road behind me. They kept looking at me with a kind of puzzled look on their faces. After a while I hollered come on around boys! This is as fast as it goes!
BOY did that make THEIR day! I was happy too!