Here is what I did for a short term fix until a new dome can be ordered. Did this in the camp ground this spring. I was "in the bath room" and hear drip, drip... oh no, what??? I was lucky the snow on the roof had just started to melt and I found it before any inside damage came. This dome crack can make a mess if it is leaking for 4 months with the camper in winter storage. I also carry spare Eternabond and other items to fix these mini diasters on the spot.
The offender...
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Cleaned it and stop drilled
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Put Eternabond on the outside
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Went inside and put EB there too.
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Here is an alternate place to the EZ tops. Icon Direct out of Canada. I have been pleased with the quality I have bought from them. Bought my replacement AC shroud. The shower top is still to come.
http://www.icondirect.com/skylights/Good luck and hope this helps
John
PS. I also spray the dome with 303 UV protectant and all other plastic items up there each time I wash the roof. About 4 - 5 times a year. The sun is a killer on anything plastic up there. The 303 really helps