New bump stops allowing water through

[Estoril]

Hi guys. A few months ago my amplifier ended up under water when water was getting in the trunk. I replaced a couple of parts to solve it and one of the issues was the old bump stops for the rear hatch were blown; the gaskets had small holes in them, allowing water through. I bought the upgraded spring-loaded bump stops and installed these. Asked the dealer if any sealant should be used but they said no, it's just a straight forward replacement part.

I tightened it best I could with the 30mm nut on the back, but yesterday I noticed that even now water is still getting in. Back when I installed the new ones, I made sure to add some towels right on the 30mm nut to make sure water would not destroy my brand new amplifier. Yesterday I took a look at the towel and the right side was completely soaked in water (it's been raining a lot last 2 weeks).

Should these bump stops be installed with sealant or something?

EDIT: The OEM number is 51247171558