04-20-2017 09:50 PM
No. No. No.
Do not put large amounts of grease on the O-ring. That will stop the case from making a proper seal. How do you think your precious GoPro will like getting hit by a high-pressure jet of water? Not very much.
Note: you do want to very lightly grease the O-ring every so often do it doesn't dry out. Essentially wipe a thin layer on, and then wipe every last bit off after a few minutes. That will keep the o-ring from cracking.