A bit like the old car windscreen.
Fit new rubber seal around frame get some strong twine vaseline the twine so it stays inside the rubber gap the window will fit in. [Two person job]press the window against the rubber seal pull on one end of the twine outwards to pull the rubber over the window keeping the window pressed against the rubber. Done this with my old car. Mind you there may be a tool available ask at your local c/van service centre and flutter your eyes at them, they will fall over themselves to help.
Bob, August 2009
