In my nearly 20 Years of using youtube, this is the first time I have needed a tutorial that not only solved the problem easily, but was also succinct and straight to the point. My Bissell steamer looked nothing like the one you fixed but was still the same issue. It's actually insane that Bissell does not have this fix on their website for "knocking noise but no steam" as a potential solution... They probably WANT people to throw them away and buy a new one. Well earned like and subscribe.
I literally just had this problem and to take the ball off you have to remove the whole rubber hose it's attached to my taking off the tank and removing the plastic plug.
You may of already found out by now, but it removes minerals build up like calcium or like will take a penny that's turning green and turn it back shiny. Removes rust type cleaner.
