If it is only at the edge of the front cap, you may want to take off the aluminum trim and apply new butyl tape/putty. Many rv's have the older oil based sealer applied at the factory. It usually dries out and cracks with vehicle movement.
Butyl stays pliable. You still don't have to remove all the old caulk, just enough to remove the screws and trim and where the actual leak was. When you get it off you'll be able to see where it was leaking.
Clean it good before re-applying. I use mineral spirits as it start to dissolve Dicor type sealers and the putties and gets the imbedded dirt out. It won't hurt the EPDM if you touch it on the rubber, just wipe it dry after cleaning. And again, just get the dirt off, you don't have to remove all the old sealer if it isn't leaking.
The three factory caps that I've resealed all had 1 strip of putty under the trim only. I put them all back with a strip butyl between the cap and EPDM and a strip under the trim.
I use the plastic putty knives also. They are cheap and less likely to cut the rubber but they will if pushed hard. They can also be re-surfaced on a grinder or with a file when the edge gets messed up.
I you accidentally damage a small spot it's no big deal. When you're finished, put Dicor on it as you would any small damage to the roof.
Joe and Evelyn
