A little while back, I noticed that out of now where my brakes lost most of their efficiency, i had to pump them 2-3 times to stop in a reasonable distance. I checked the fluid and it was a little low in the back, larger part of the master cylinder. The vehicle is a 1974 gran torino 4dr with discs in the front and drums in the back. I refilled the fluid, no change. I found that some fluid was leaking out the master cylinder lid seal, after fixing that and having no change in the brakes, I tried to bleed the brakes. Starting in the back, the bleeder screws on both sides were stuck. I got the passenger side and impatiently bled that drum. I couldnt get the driver side drum and I didnt have time to buy a new wheel cylinder so I moved on. I went on to the front brakes and bled out a lot of air on both sides. I didnt expect to have the brakes back fully, but there was no change at all in performance. I expected some change. I still have to pump the bakes 2-3 times. Someone please tell me if buying a new wheel cylinder and re-bleeding the brakes might fix this, or could there be something else. Why could this have happened out of nowhere?