[Tim7139]

Be advised, let it run a longer than you might think without the cap to really burp it completely.
Recently I lost a stud on my surge tank flange and had to take the level down to pull it off and replace the stud/gasket. This was far less than you've experienced with the lower hose and it took a hell of a lot longer than I would have guessed to burp and get all the bubbles to stop.