parbond over existing sealant
So my trailer has a leak and I believe that it is coming from a vent on top. Unfortunately, when I got up there, I see that the previous owner must have used a full tube of vulkem or parbond around the seam. For the most part, the seam looks intact but in several places, the sealant is cracked. Ive been trying to get the stuff off but its a whole lot of work to pry that stuff loose. Im not worried about aesthetics since it is on top and no one will see it. Can I just clean and fill the cracks in the sealant with new parbond or vulkem? How effective is this in your experience?
Also, if I do need to get the existing sealant off, how thoroughly does it need to be cleaned? Do I just need to get the bulk of it off or am I going to need to get it spotless? Anyone who has tried variations of this please let me know what will work in your experience. Im not looking to put hours and hours of work into this right now.