311 Low Windshield Removal Section
Removal of the chrome windshield frame is not a big chore. There are two sets of bolts on each side of the frame and two bolts up under the dash close to where the wiper pivot arms are. It is best to remove the seats to get at the two up under the dash. Once these are removed the frame can be lifted from it's mounting place.
Next find a nice soft place to lay the frame and windshield down on. This is especially true if you plan on reusing the windshield. I believe they are NLA from Nissan and very exspensive to buy if you need a replacement.
Most likely several of the eight bolts holding the frame together in the corners will be rusted solid. Get a small ziplock bag to put all the bits and pieces in. If you have one snap off on you do not fret. You may bugger the head up in your over zealous attempts to remove them as well. If you do bugger a head get a 3/16th drill bit and drill motor and drill the head off. I had to do this several times. You can usually get a pair of vice grips on the stub once the frame is apart and get the bolt out from the back side. If you have a really stubborn one you may have to carefully drill it out and run a tap to clean up the threads. I have a habit of running a tap even if there were no problems just to clean up the threads for new bolts. There will be two more bolts holding the center bar in place. Same treatment here if they are stubborn-drill them out.
Next, you can carefully seperate the side pieces from the top and bottom pieces. There are some small trim pieces that go over each corner at the top on the 67.5's. Slide them up and off without bending them and put them in a baggie with the rest of your removed hardware. Carefully set the glass aside and begin removing the old gasket material.
Gaskets are still available from many of the vendors. A complete set consists of seven pieces. Four pieces for the windshield itself-two sides and a top and a bottom. Two pieces that go on the outside of the metal lip flashing on each side piece. And one piece for the very bottom of the frame thet sits between the frame and the body. The four pieces that fit around the windshield will need to be cut to fit. Go slow and think about what you are doing
If the frame requires replating send it out and gather your new hardware to reassemble the frame. If the frame is okay and you are going to use it as is you can begin reassembly after tapping out all the holes and purchasing new fasteners. Carefully cut the bottom weather strip leaving it a bit long. You need to angle the ends so they will butt up against the side pieces. I do not recall what degree the angle is but go slowly until you get a good fit. Cut the bottoms of the side pieces to match up with your bottom weatherstrip. Now, loosely assemble the side frames to the bottom frame sliding the windshield with the bottom gasket into place. Slide the side pieces into place checking the fit. Mark and cut the tops of the side pieces making them a little on the long side as before. Cut one end of the top weatherstrip and line it up with the side piece. Slide the top weatherstrip over the glass until you reach the other end. Mark and cut it and slide it back into place. Grab the top frame and fit it over the weatherstrip. You may have to trim small amounts to get it to fit perfectly. Once you get it where you are happy with the fit bolt the top frame to the side frames. Tighten all the bolts securely. Reinstall the center support bar.
Next you need to install the bottom weatherstrip. It is a bugger to keep lined up. I used 3M adhesive to hold it in place. Start from one end or the other and use blue painters masking tape to hold the darn thing in place as you work your way along. The original installation had some pliable putty between the weatherstrip and the body. You should be able to get some putty from any good autobody supplier. Once the is set you can reinstall the frame securing it with the six bolts-two each side and two under the dash. That pretty much covers removal and replacement of the windshield, gasket and frame. Good luck.