Classic/Antique Car Repair: Restoring a 1934 Chevy Master, window gaskets, gasket material

Question
QUESTION: Can you recommend an efficient and easy was to install the rear window. The window fits into the gasket, however the gasket is extremely tight.  I have broken 2 windows trying to get them in.  Can I shave the gasket?  It only needs an 1/8th of an inch.  I am trying all.  Thank you

ANSWER: I have never had any success shaving window gaskets to make them fit. Is the gasket that you have a new one or the old one? A gasket should slide onto the glass snugly but without force. Steele Rubber Products (http://www.steelerubber.com/rear-window-weatherstrip-by-the-foot)sells window gasket material by the foot. I have used their products over the years and they work well. Now when using the by the foot gasket fit it around the glass and trim to fit with the joint at the bottom of the glass. Then once installed seal the joint with black RTV silicon.

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QUESTION: Thank you for your suggestion. It is a new gasket, one continuous piece and does fit snugly around the glass. I am inserting the glass, which is in the gasket,from the inside of the car(backseat)to the outside.  The gasket has a seal that when pushed in seals the outside of the rim of the window.   Thanks again Pat, 1934 Chevy Master

Answer
Most glass that I have installed go in from the outside. I usually wrap twine in the groove that seals to the body. Put the ends of the twine at the bottom. Then place the bottom of the glass with the grove in place in the body opening and pulling the twine around to bring the sealing flap into the body. This is a two people job, one outside applying light pressure on the glass and one inside working the flap into place.