Windshield removal for a high screen Datsun Sport is not at all similar to the low windshield, as the frame is not removable on the '68 an up models.
Start with three large flat bladed screw drivers. Position yourself in the drivers seat and start at the top middle. Push down the rubber to expose the metal lip and insert screw driver blade under metal lip to hold rubber down. Insert second screw driver blade close to first and fold down rubber exposing more metal lip. take third blade and continue folding down lip. Remove first blade and repeat process, making sure that the rubber does not pop back over metal lip. Do the top lip all the way across. Do the sides next. Once the lip is exposed on all three sides, gently push the windshield out from the inside of the car. Have someone on the outside catch and balance the glass.
Leave the outer stainless steel insert in place. Installing the stainless steel trim is very hard and will test your patience and your thumbs. We have found it best to send the glass, weatherstrip, and SS trim to the local glass shop. For ~$70, it comes back all assembled.
Install is simple with a thin rope that you insert in rubber groove that will reverse the process in which the screw drivers folded down the lip. Insert rope in rubber seal with two ends at bottom of glass. You will need a lubricant to help slip assembly into the hole. Some people use glass cleaner. We just installed the front and rear glass in a 71 510 and used silicon lubricant. This is not recommended if you plan on painting the car after the install as this will cause havoc with your paint. Make sure that the glass, seal, and rope are centered properly in the opening. Have someone help by pushing the glass from the outside. Gently pull string up and towards the middle of the glass gently and slowly. The pulling of the rope lifts the rubber seal over the metal lip and slips rubber into place. Start one rope until you get to the first corner and then pull second rope to opposite corner. have helper push and slap the glass and the seal into place. Corners are the hardest part of the operation. Once you have removed the rope and the rubber lip is in position , you can start slapping the glass and coaxing it into position. It will be proud at first, but after some firm palm slaps it will slip into the right place.
Thanks to Ross Mullen, Sports Imports (12/01/2010)