I have a 98 Grand Caravan, front wheel drive, with ABS. I had to change one of the rear wheel cylinders. I fully bled the brakes making sure the resevoir didn't go dry. About a couple of days later the brakes went from firm positive stopping to spongy pumping to stop. There was no apparent loss of brake fluid so I bled the brakes again and found air in the rear wheels only. Bled a full liter of fluid thru the system and chacked all the rear fitting to make sure they were fully tight. The brakes finished hard with good stopping. A week later they are back to spongy again with no signs of fluid loss. This problem seems to occur after the ABS as been tripped a number of times. Is there any chance the ABS is somehow introducing air into the rear brake system? I can't keep having it bled and can't afford the repeated garage trips. Can anyone give me an idea.
