Brake emergency

Good grief. Some posts read like these brake systems should never have been allowed on the streets. The car is what 50 years old ? over 100K miles ? and hasn't hit a wall ? Some luck huh ?
If you are resurrecting the dead, of course you should replace 100% of the brake system. Routine maintenance is just what you've done, inspect carefully, service/repair/replace as deemed necessary.
From what I've read, these modern model hoses with metal straps crimped onto them have a higher failure rate.

Not some luck, but you just pointed right at the problem. The car IS 50 years old with over 100K miles. That's well beyond the service life of the rubber items in that brake system. For that matter, the hardlines should be inspected closely. Keep in mind, brake fluid sucks up moisture like a drunk at an open bar, so the insides of those lines could be worse than the outside.

I won't go as far as saying that a stock 9" drum brake system shouldn't have been allowed on the street then, but with the average 200 dollar import beater being able to stop three times better on bad tires now, it is something to consider.

We now return you to your regularly scheduled brake analysis.