Alright thanks! I'll try that out, also just realized the tank is being pressurized I'm sure that's not helping. The seal looks pretty rough too.I have taken mine off a dozen times already playing with different pumps and so forth. I once had an issue with the ring not being on properly and was leaking fuel.
I would make sure to remove the seal and reseat, then try screwing the ring on again. It can be a little of pain. Just go slow.
Here's the part numbers just in case you need a new one I see many online. Ring MB867374 Gasket MR342213