Alright, 92 XJ Larede 4.0 4x4

I know there have been a few threads about this one but mine is a little different, bought my jeep a few months back. And brakes had been fine. Once or twice when slightly braking they would grab hard and the jeep would nose dive. And then after letting off the brakes the brakes would be fine after, well a few days ago it did it the second time, and my brakes became softer, as in my pedal goes further towards the floorboard and it takes more to stop, still had decent stopping power, but when braking the red brake light comes up on the dash. And once i stop braking of i tap the brakes the light goes off, its the same light that comes on when E-brake is engaged but it os not engaged, checked the reservoir. Still full never moved, checked all lines at all 4 locations, everything checked out alright, so I checked my hardware. Pads weren't too bad off. But the rotors were rough. So I went ahead and changed rotors and pads. Never broke a line loose so no bleeding was needed, just pushed the cylinder back in with a c clamp, with reservoir cap off. And reservoir was full to the top with liquid after. After brake job took test run. Stopping power is better. But pedal is still soft. And light still comes on, then goes off after accelerating and tapping the break it goes off until I break again, has anyone heard of this happening? And have any suggestions? Is my master cylinder going out? Or maybe boost pump? I'm not too fluent with braking systems so any advice would be greatly appreciated.

 

While braking



After tapping brakes after accelerating