I've been having issues with brakes on my 87 Cutlass. It seems like I opened a can of worms🙁 The first problem was the car was losing brake fluid and I had no idea where is was going and no visible leaks were on the ground. So I proceeded to pull all the wheels and redo the rear brakes and replace the wheels cylinders because they were quite old. Now the problem is the rear brakes won't stop and during bleeding, the pedal won't go to the floor. I think the master cylinder is shot and or there is some sort of major issue going on. No rear brakes and I'm afraid to see if the front will still work. Anyone have any ideas how I can troubleshoot this?