My mobile home is leaking in some spots when it rains. Its all on one side. I had it repaired when I first bought it(when it was new) It was under warrenty then. Now its starting to leak again. I was told it was the sealant the manufactuer ussed wasn't any good. My son-in-law looked but he can't tell where its leaking. What kind of sealant do I need to use and where do I put it?