I just had the hydrovac rebuilt on my Chevy 1960 C60. Big difference. Now I can stop. Proportioning valve requires my attention. I also had bypassed it for general yard usage. The same person did the vac for my 1977 International 1600 the week before.
Now I need to wear a belt to keep from hitting the windshield! (just kidding). Power Brake exchange in San Jose. I highly recommend them. The old Bendix Aircraft Co, South Bend Indiana, vac is somewhat complicated and expect to pay $300.
You gotta have good brakes around here when that new Tesla cuts you off! lol