[Randy Blaylock]

The function of the aluminum trim piece is to give the rubber seal form. Specifically, you can use it to put the seal where you want it.

For example, on the front winshield, if the corners of the seal dont go far enough into the windshield opening in the pan, leaving gaps for water to run in, if you take a small rubber mallet, and VERY CAREFULLY strike the aluminum trim, you can drive the rubber seal in any direction you want. The aluminum holds the rubber seal in whatever shape you want. Another tool you can use would be a small piece of wood, like a shim wedge, with a small curve sanded into the end that will be applied to the aluminum trim.

On the rear glass, the same principle applies. Just be careful, swinging the mallet so that it's almost sweeping over the surface of the glass, trying to lightly impact the edge of the aluminum trim, driving it in an outward direction, especially in the corners.