I had contamination in my system about two months ago so i replaced my 4 calipers along with the 4 rubber hoses goin to each caliperand the abs unit. And ever since then my pedal would never come back to the top u would have to pull it the rest of the way up with ur foot. Then someone told me to replace the master and slave cylinder so i did and it is still the same, so if anyone has any ideas it would help out extremly.