I have a 99 blazer 4wd and last weekend while pulling our camper I had to stop quickly and got a leak on the brake line in a rusted area right under drivers seat that goes to rear brakes. I was able to keep keep adding fliud to the cup in order for us to get home. the next morning I went out to replace that brake line and all the brake fluid had drained out of the cup. So I replaced the that brake line from front to back. then I filled the cup and had my son help me bleed the brakes. I bleed all the 4 several times and there is no more air coming out. But the pedal still travels a ways before i get any pressure and I seem to only have front brakes that are stopping the blazer. the back calipers close but not enough to do anything. Also the warning brake light stays on. I checked everything over and there are no leaks. the cup is also full. With the cup going empty could air have gotten intot ehabs system and this is causing the problems. I read online that I would need a scan tool to bleed the ABS. Any help would be greatly appreciated. I would have thought after replacing the brake line that evryhting would be ok.

 

You can try bleeding the master cylinder also. Seems to happen a lot with trucks that leave it empty for a while

 

As said, you need to bleed the master cylinder. Disconnect the lines and get some short pieces of brake line with the proper fittings. Loop them back up to the reservoir and pump the brakes until no more are comes out and until there isn't a flow of fluid into the reservoir as you press on the brake pedal. Then reconnect the lines and bleed the rest of the system.