They are just a simple fork seal like any other fork. So when they fail, they should be replaced. Mine failed at about New River Gorge on rt 60. By the time I got home, the front of the bike had an oil residue all over it.
Got the bike outside, rode it around the block and washed it. Fork springs are on backorder so I have to wait 2 weeks. Still need to service the driveshaft and grease swingarm pivot.
Definitely try to get the corrosion cleaned off the bead. For stubborn tires, sometimes a ratchet strap around the circumference helps, as well as a bead blaster that can shoot a ton of air at once.
I've re-applied new 3M tape without issue. Gotta get the right thickness. I also run a tether like the ones in the link below if I am nervous about where I am mounting it.
https://www.amazon.com/BeneU-Tethers-Accessory-Adhesive-Stickers/dp/B00W4XTWTQ/ref=sr_1_3?ie=UTF8&qid=1487392054&sr=8-3&keywords=gopro+tether