I have an interesting brake problem. I drove one night for around an hour and the brakes worked fine. Got up the next morning and the brake pedal was very soft and would brake a little but the pedal went almost all the way to the floor and the stopping power was much less than normal. The brake light is on, but there is not any obvious leaks anywhere (that I can find) and the fluid level is ok. It might have been a TINY bit less than totally full, but the fluid looked pretty dark. Could there be a really slow leak somewhere? Also no ABS.
Thanks in advance.

rear brakes ,,every time i have a pedal go to floor on ANY car its rear brakes. my 2000 had rusted line from master cyl to rear axel .replaced and bled,at the conection on rear axel. solid pedal.
look close for small leak that empties the line

i replaced all from master to rear axel. i have no abs,,,,

adjust the rear brakes, but I'm guessing your master cylinder is bypassing internally.

Oh, changing brake fluid. Hardly anyone ever does it. They should.

Pulled rear tires and on both sides only the front drum pad moves, not the rear, is that ok? Or what's the issue

I have always had issues with weird brakes. I always run normal brakes instead.

Open passenger rear bleeder until fluid runs out. Remove master cap and keep full. Then bleed pr, dr, pf df.