Cadillac Repair: 89 Deville brakes, accurate diagnosis, flex lines

Question
I have an 86 Deville , I replace the rear brake cylinders and shoes , front calipers and pads. After bleeding the system the brake pedal is very stiff and car is hard to stop. All the brake lines look ok , no pinching and flex lines are not that old.Master Cylinder is not that old.
What it almost feels like is that there is not brakeboost.
Any Suggestions would be helpfull

Answer
Without actually testing the system personally, An accurate diagnosis is most impossible.

However, with the engine running put your head down near the brake pedal and push the brake pedal with your hand and if you hear a a sound like air escaping when you press the brake pedal this would be a faulty brake booster.

QUESTION: WHY did you replace the brakes ?.

QUESTION: IS or HAS any of the dash lights such as the CHECK ENGINE or other warning messages ever appeared on the dash that is not usually there when you drive the vehicle ?.