Jeffro,
Welcome aboard to the forum and

on your video's. I think we have used some of them here in the forum.
Anyway to your problem I just have a couple of questions to ask.
1. Are you making sure that the diaphragm has not partially dropped in when putting the cap on?
2. Do you have a washer (about 1.5" dia) on the outside of the diaphragm?
If you have the large washer on just remove it and see if it improves things.
Let us know hoe you get on please because it helps all the members here.
