Been bleeding brakes after rebuilding all 4 caliphers and replacing the Master Cylinder. Now when I am pumping brakes up I can hear a hissing noise from the vac pump up front. I don't know how long that has been going on but I have noticed a slight run on when I turn ignition off (2 to 3 seconds). Also I have noticed a slight flair in shifting every now and then. I am wondering if the diaphragm has/is getting a tear in it. Does anyone have any experience with the diaphram in the pump going out? Can that be changed out pretty easy? Thanks for the help!