Power Assist Brake Vacuum Hoses, Lines/piping, And Fittings problems of the 1999 Ford Expedition

I have a 1999 model Ford Expedition. I had had a problem with the brakes. The pedal effort to stop was sometimes very high to make even a gentle stop. The problem was intermittent. I am capable of enough force on the brake pedal to always stop safely but the changes in effort required were surprising. The front pads and rotors were changed last year. The rear brakes were also checked. The brake system seemed to act like the engine was not running to provide the vacuum for the brake booster. After some close calls on the work commute, I decided to check the vacuum hoses between the engine and the brake booster. This vehicle has the brake booster vacuum line running across the firewall behind the engine, connecting to a 'y' to include the pcv valve and then onward to where it connects to the intake manifold. On my Expedition the hoses near the 'y' for the pcv valve and the hose on the manifold were soft and appeared collapsed when the engine was running. The hoses were not reinforced like brake booster vacuum source hoses on other systems I have seen. These looked like bigger diameter versions of the common all rubber vacuum hose. I replaced the soft, collapsed hoses with braid reinforced 3/8 fuel line hose and now I have power brakes every time. A small person could not stop an Expedition safely without power brakes. The intermittent loss of vacuum boost was surprising and frightening. I still have the hoses I took off.