Hey folks, I have an Iwata Eclipse HP CS. I'm having an issue where, when I spray, it intermittently and rhythmically pulsates air. When I push the trigger with no paint, I get little air bubbles in the water in the tank. The brush is clean and I'm experiencing the issue with just water. Now, in researching this issue, it turns out I've been making a mistake. I've been soaking my whole (disassembled) airbrush in Medea airbrush cleaner in my ultrasonic cleaner. Apparently this can damage the O-rings which can lead to the issue. I want to take a look at the O-ring labelled #7 (packing valve piston oring) in the attached picture, as the O-ring labelled 5 (packing head oring) looks completely fine and airtight (but maybe looks are deceiving). But I can't figure out how to open up that part of the brush. My head cap is screwed on as tight as I can reasonably twist it -- I've read that cap being loose can cause this issue as well. What should I do? What else could cause this issue if it's not the O-ring? What other steps can I take to debug this issue? I'm really at my wits end here. Thank you.