1926-1932 Fisher "VV" Windshield
1926-1932 Fisher Body closed cars, including most Chevrolet, Pontiac, Buick, Oakland, and Cadillac's had windshields that cranked up to allow air to circulate into the passenger compartment. This was referred to as the Fisher "Vision & Ventilation" system. In this system, the windshield glass is held with an upper sash channel and slides in rubber channels on either side of the windshield. The glass is lifted with a windshield regulator that sits above the windshield and connects to the upper windshield sash channel. The regulator mechanism has pot metal gears with a crank handle. Cranking the handle will raise and lower the windshield glass several inches. As the windshield glass is raised, air flows into the passenger compartment, hits the curved part at the top of the dash and is directed downward onto the floor area.
The weakest part of this system is the pot metal gears used in the windshield regulator. If the mechanism gets stuck and the handle is turned too hard, it can damage the gears of the regulator. Because these are only pot metal (die cast), they are very weak and strip out easily.
If your regulator is stuck - DO NOT FORCE IT! Instead remove the header board that holds the windshield regulator. There should be two screws at the each end of the regulator board. In addition, there are usually two or four screws at the top in the middle. After the screws are removed, the board should slide out of the upper sash brackets by pulling straight back. Once the regulator board and regulator are removed, check the movement of the windshield glass. The glass should slide up and down easily. If stuck or sluggish, try some silicone spray on the side channels to free up the movement.
If the glass moves easily, the next step is to check the regulator gears. The gears in the Chevrolet windshield regulator were pot metal until 1932. In 1932 steel gears were used. Lubricate the pivot points and gear teeth. Install the regulator handle onto the shaft and gently work the gears back and forth. If the mechanism is seized and will not free up, installing replacement of the gears may be necessary. New gear sets are available to replace 1929-1930 & 1931 windshield regulator gears.
One thing to check when working on your windshield is to make sure your windshield glass is laminated. Prior to 1932, Chevrolet used only plate glass in their windshields. This glass is very dangerous and should always be replaced with laminated safety plate glass. New rubber seal kits are available to replace original brittle windshield seals.