The gasket on my windows was old, hard and did not give a proper seal. I purchased all new gasket material for all the windows and went to work. The windows on my 78' are extremely easily to remove. Open the window a little. Remove the screw at the base of each arm that is attached to the frame, and slide the arm out of the channel in the window frame. Now that the window is free to rotate around the top of the window, you lift the window up so that it is almost perpendicular to the trailer and the window will just come right out. Installation is just the opposite. The window has an extruded channel at the top that "hooks" into the channel on the window frame. After the window was out, I put it on the workbench and removed the old gasket. I used a putty knife and a bunch of lacquer thinner to remove the old gasket and glue. It takes a while to get the frame clean of all the old glue. After it is clean, I applied a 3M gasket adhesive to both the frame and the gasket. I cleaned both with lacquer thinner first to remove any contaminates. I used an old tooth brush to apply the glue. It works like a contact cement. You must put it on both surfaces and let it dry to the touch. After 10 minutes or so you can start to re-attach the gasket to the window. Fairly simple process, but with (6) side windows and a front and rear window it took 2 evenings after work to complete the work. I feel pretty good that all the windows have new rubber and will not cause me further trouble with leaks.
