Resealing rails, I suggest looking at Awning Rail- Nearside first, it is the latest and shows the techniques I use. The others show what was involved and issues that came up.
Caravan Rails- dealers' may do it differently, but for DIY I find it best to use a combination of W4 mastic in the centre of the rail and Sikaflex 512 Caravan on the sides. Sikaflex leaves a good surface that will not discolour and become dirty.
The pictures below show the results,
Page Created 7th March 2007/Updated 24th April 2011