Marv and I went to the same school of windshield installation, I have done a few, cracked one, said no more. As others have said, you need to puch and pull and such, and it is easier if the frame is solidly mounted to the car. After I broke one trying to install on my TR250 I had the safelite guy come and do it, he was freindly and willing to let me watch and learn. I thought I was being smart by usinng a thin strong piece of twine for the rope trick to pull the seal through, wrong, first it can break, second the thinner stiff is more likely to rip the rubber seal rather than pulling it out. A quarter inch nylon cord and plenty of soap or your preferred lubricant is the way to go. Having watched the guy and hopefully learned a few things I might do it myself again, but then again they will do it for you pretty cheap, and if you buy the glass from them they will pay for it if they break it.