Got a 92 blazer that the brake pedal goes to the floor and is spongy, but also fades/sinks when holding it. I've bled all 4 wheels twice, 1st time bled old out until new came through, felt spongy and goes to the floor, 2nd time I bled I had pumped 10 times then held to purge out more fluid, did that 3 times each wheel, made no difference. saw only a few little bubbles on a couple wheels, acting like tons of air in lines. has ABS, can the ABS master cylinder be bad? replaced the main master cylinder before I bled the brakes at all, made no difference. I also pre-filled and purged the new master cylinder after I got it. Went through 2 new ones thinking it was the master cylinder having the problem. If i possibly still have air in the lines, how many times will I have to pump and hold before the front and back lines purge completely so I know for sure it has no air?

didn't help, bleeding makes no difference. even tried another brake booster thinking maybe vacuum leak in it, everything is same, nothing at all better. Doesn't seem so much to feel like air in lines anymore, but weather you mash the pedal trying to lock up the tires or apply even and firm pressure, it's seems to stop at the same rate. Can't quite get even one tire to lock up solid as hard as I try, maybe that's the abs actually working but it feels like the pedal is sluggish and it takes way too long to stop, like the pedal is stiff and you can't seem to get it to go down fast enough to stop quick enough. I would also think if it's the abs doing it's job, it would make the pedal vibrate as well as the brakes, always smooth.

Thinking of just running lines straight from the master cylinder to the wheels with maybe a junction block in between. No abs or any kind of braking assistance to interfere.

I just can't think of anything else but the abs giving me problems right now. didn't help, bleeding makes no difference. even tried another brake booster thinking maybe vacuum leak in it, everything is same, nothing at all better. Doesn't seem so much to feel like air in lines anymore, but weather you mash the pedal trying to lock up the tires or apply even and firm pressure, it's seems to stop at the same rate. Can't quite get even one tire to lock up solid as hard as I try, maybe that's the abs actually working but it feels like the pedal is sluggish and it takes way too long to stop, like the pedal is stiff and you can't seem to get it to go down fast enough to stop quick enough. I would also think if it's the abs doing it's job, it would make the pedal vibrate as well as the brakes, always smooth. Thinking of just running lines straight from the master cylinder to the wheels with maybe a junction block in between. No abs or any kind of braking assistance to interfere. I just can't think of anything else but the abs giving me problems right now.