[Richard]

I use a rubber strap wrap wrench too. And I put silicone on the o ring when reinstalling. It still takes a strap wrench to break it loose. It’s a bit of trouble but if you will take the time to remove the shutoff handles you can remove the cover panel. Much less likely to slice your arm when the housing breaks free that way. You can get a nasty cut working in the confined space if not careful. Don’t ask how I know this.

When you are describing the 12V pump as surging. Is that with the water flowing or just with static pressure? If with water flowing, then it may be an artifact of the pump behavior. Adding a surge tank will certainly smooth that out, and I can’t imagine it hurting with the Headhunter. But it is overkill for the HH design. Check to see if there is a check valve in the line after the 12V pump.

Being somewhat of a pragmatist, how often do you think you will use the 12V pump? We only use ours when dry camping to conserve water and battery. For us that is maybe 2 or 3 days a year, and we use the coach 6 months continuously per year. My 12v will surge a bit unless the water tank is about 1/2 full, but once I get it primed and the air out of the 12V system, it calms down. Try running a bit of water using the 12V pump only and see if it calms down. After all, you did break into the system and there could be an air pocket somewhere.