Since I never caulk the roof before I have some questions! This is on a fiberglass roof, when I was at the factory I got some CSL Silicone caulk is that what I use, or do I want the self leveling kind...
I just remove the loose caulk and apply the new caulk over the old. I would remove as much caulk as possible around a leaking area before putting on the new.
Always clean well before applying caulk. I Use Dicor self leveling on the horizontal areas.