I had this issue on one of my bikes and resolved it by pushing the pistons out some, cleaning them with iso alcohol and qtips before pushing them back in. There was enough dirt around the pistons to keep them from being able to fully retract. A mechanic at the bikeshop had the same issue while I was there and opened up one of the bleed screws to release some of the fluid, which served the same purpose but I didn’t want to remove any fluid from my system.
On a barely related note, I’m growing to detest Avid’s brakes simply because of the bleeding hassles. I just came up from the basement where I finished bleeding an Avid 5 for the fourth time, trying to get the squish out of it. Each bleed continues to improve the feel a slight bit and gets a bit more air out. Contacting Avid, I was told that it was common to have to bleed the system multiple times.
Yes..You are right schwim. I had faced also same problem and by applying above method solved easily.
Thank you