Brake pedal sticking to floor

Hi, so as the title states, my brake pedal (more often than not) sticks, I have an 84' caddy from South Africa and from what I can tell the servo and mc aren't original, the servo is 9" in diameter and the mc has 2 ports and reservoir on the top (small reservoir) my brake light switch is a plunger behind the pedal so I'm assuming that's also not standard. Seen another post on here which sounded like the same issue but there was never any follow up on whether the issue was solved, any help would be great

Are the brakes binding after applying them, or is it just that the pedal doesn't return all the way?