I want to point out another common area for a air leak that I see in one of your pictures above - the spout that is on one of the two diverter valve housing end caps. The spout is pressed in there, and loosens with time/age, and it is a good idea to put some good ole' JB Weld around the perimeter. I put some on with a small screwdriver, and spread it out nicely with my finger (my middle one, Paul) - looks just fine if you take care when putting it there. Don't do like Brando (quatrorunner) and use a whole friggen tube of the stuff and then put it on with a tooth brush!!!!!
And good job on getting your hands dirty so soon!
