Brake Goes Soft while pressing it

I got a 91 integra non ABS everytime i step on the break it starts going down, I have to keep pumping it to get hard and then it starts going soft and soon as i stay on it. and when i'm a full stop i have to push it to the ground to stay stopped. i tryed bleeding the breakes but still the same way. can someone help please. thank you.

hey this happened to a ford i used to own n im not 100% percent if this is the case but where the brake fluid is check if there are air bubbles when u press the brake because their might be air getting into ure brakes therefore the vacuume has to be replaced. tell me how it goes.

Master cylinder or air.