Help me find a leak? Brian, I had the same problem with my cap on out Travel trailer. I removed as much of the old caulking as possible and caulked the entire seam.. Unfortunately we noticed an odd smell the weather warmed up. Finally had a reliable rv repair man take a look . Together we removed the entire cap and found some dry rot under it. This fellow is a good friend and knows what he is doing so the job was reasonable price. Took about 8 hours total. Total cost with materials $400.00.