I have a 2002 Dodge Grand Caravan with a 3.8L auto and abs and also is handicapped modifed, my problem/s, recently the rear calipers started to stick, I told Dodge tech that we saw smoke coming from the left side but he said the right side was the problem, they replaced both rear calipers and pads. We left and all seemed ok. A couple of weeks later the front left caliper started sticking, I replaced both front calipers and pads, blead the system and I have soft brakes, I then replaced all of the hoses and the master cylinder, blead the system numerous times and still have soft brakes. I read in a repair manual that the ABS must be computer blead so we took it to our local Dodge dealer they kept it for 2 days blead it numerous times and it is better but not right, now they want to replace the master cylinder. All the parts that were replaced were remans except the pads and hoses. Oh I almost forgot, about 2 weeks prior to the local Dodge dealer replaced the front rotors and all the pads

 

If the dealer had the brake system apart and then and only then,you had problems they should be responsible.
It sounds to me that there is a problem with the master cylinder.It could be the fluid was so dirty that it had carried dirt into the lines and caused a blockage.A good place to start would be with a reverse flush to force any blockages back up into the master cylinder but with ABS I don't know if that would work.Taking apart all the lines and blowing them out with compressed air might be an option if nothing else works but bleeding the system after doing that might be a severe pain.