The fix is easier than replacing the hose, but it is the rubber hose that's doing it. Look for the metal bracket that is crimped around the middle of the hose. Rust builds up inside that crimp and constricts the hose. Foot pressure can push fluid through but return spring pressure can't push it back. Your dandy observation of opening the steel line, (or bleeder screw), was the clue most people overlook.
Thursday, April 14th, 2011 AT 6:02 PM