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Chevrolet Corvette Window Restoration

Project Shark Attack Gets Window Regulators

Chris Petris Oct 29, 2008
Corp_0601_01_z Chevrolet_corvette_window_restoration Plate_screws 2/17

This plate with four 71/416-inch hex-head screws connects the front window vertical-guide track to the door. All four 71/416-inch screws and the plate must be completely out to remove the front roller with the window glass. The outer screws holding the plate allow movement of the glass inward and outward at the top. Inner screws move the window glass front and back. The anti-rattle stop to the left of the photo must be removed also.

Sooner or later you'll need to repair or adjust the side windows in your Corvette. Nagging concerns can arise after the repair, such as, "Will the window work as well as it did before the repair?" Maybe you're doing a restoration and gutted the doors. Now the pieces of the puzzle must be put back together. Once reassembled, the windows must be adjusted, which can be frustrating.

Project Shark Attack was the perfect candidate for a mechanism overhaul, as neither window would go up. Pulling the window up with a pair of vise grips to hold them in place is a bad idea. With windows in this condition, a complete overhaul is best. When the window regulator and motor gear-teeth are worn out, it's likely the hardware is in similar shape.

A total window restoration is almost always necessary with a 25-year-old-plus vehicle. We've taken heat in the past because we rarely replace just the broken part. My father, Chris Sr., taught me a job worth doing is worth doing to the best of your ability.

Parts are available for our Shark's window mechanisms allowing like-new results. The window mechanisms should be evaluated carefully and the necessary pieces ordered before gutting the doors. Take as many photos as possible.

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Window evaluation starts with trying to rock the window fore, aft, inward, and outward. There are window rollers (bearings) bolted to the glass that guide the window's vertical and inward/outward movement. If the window flops around fore and aft and drops easily when pulled outward, the rollers are worn.

The front roller guides and pivots the window against the anti-rattle stops and outer seal strips on the top of the door. The outer seal strips are important for window fit and adjustment. Early reproduction outer seal strips were constructed of rubber. Later seal strips are similar to the originals and have a flocked cover. The original style costs more but is worth it for the correct look and proper window adjustment.

The rear roller is also a rolling pivot point for the rear of the glass. It's common to find the front roller worn badly and the rear roller in good shape. Worn rollers make the window appear properly adjusted, but when closed, it's out of position again.

The window regulator has rollers at the end of the lift arms to ride in the tracks. The roller regulates the angle-control track roller. When this roller wears, the window lifts at different angles each time making adjustment difficult. While lift-arm rollers can wear, they usually don't affect adjustment.

For our project, we decided to show both options-installing new stainless steel window regulators as well as rebuilding originals. Rebuilding the original regulators took time, but with Corvette America's components, they were brought back to life. Corvette America has all the pieces necessary to replace worn components, providing like-new quality. Whichever you chose, examine the regulators for worn components and replace or repair them while apart and accessible.

Project Shark Attack had worn regulator gear teeth and power window motor gear teeth causing zero window movement. We found a new driver-side window motor and a previously rebuilt passenger-side window motor to replace the originals.

Corp_0601_09_z Chevrolet_corvette_window_restoration New_regulator 10/17

We're working with a new regulator from Corvette America. The motor reinforcement plate and motor are installed, then the capture bolt and nut with the yellow paint dab (by my thumb) can be removed. Serious bodily injury can occur if the arm smacks you. Install the new motor-shaft guide included with the regulator into the reinforcement plate.

Consider cleaning the door lock mechanism or replacing the door handles during the window overhaul. This is also a good time to replace power-window wiring. The power-window wiring harness takes a lot of abuse when the door is opened and closed. Sometimes a wire has broken strands, limiting the current flow to the motor. This can explain slow operation following motor replacement.

Before reassembling the window, remove all the tracks and hardware for cleaning and greasing. Wash the tracks in a mineral spirits solvent to remove caked-up grease that can slow window operation. Coat all the window tracks and rollers with a high-grade chassis grease for lubrication and rust prevention.

The final adjustment after reassembly can be frustrating because many factors affect window-to-weatherstrip fit. First, the door must be adjusted correctly. If the door is not flush with the body panels, the window fit will be affected. Finding the balance between a good door fit and enough window adjustment to allow proper sealing can be tricky. The door may require a compromise adjustment (e.g., a little in or out at the bottom) to allow enough window angle for a proper fit.

Begin the glass adjustment with the plate on the front vertical-lift arm track, which positions the glass to the front or back. Center the window with the plate and carefully close the door. Look at where the window sits. Does it need to go back or forward? Note the rear of the glass. If the window is too far back, it can catch on the top rear corner and take off paint.

Corp_0601_10_z Chevrolet_corvette_window_restoration Rebuilt_motor_used 11/17

Because new motors are discontinued, we used a rebuilt motor on the passenger side. We replaced the driven gear with a new Corvette America assembly since ours has worn teeth and internal clutch pieces. When the regulator gear wears, the driven gear is usually in bad shape. Lube the driven and pinion gears well with the supplied grease.

If the window is centered, examine the upper part of the glass. Is it too high in the back or front? The upper limit stops control this position, and in most cases, the balance track needs adjustment to allow the window rollers to fit tight against the stops. This keeps the window traveling smoothly into the stops. Adjust the upper limits to the best position until the next adjustment is completed.

The rear vertical weatherstrip is fixed so the glass should be fitted against it. This concerns the inward and outward movement at the top of the glass and how the glass fits against the rear vertical weatherstrip. This is usually done with the front vertical weatherstrip removed from the retainer on the windshield post. Move the rear vertical track so the glass has even pressure from top to bottom.

Once the glass fits at the rear, adjust the front vertical weatherstrip retainer to fit. The one on the windshield post can be moved inward or outward so the glass fits with equal pressure top to bottom on the weatherstrip.

Next we tackle the T-top weatherstrip-to-glass fit. The T-top weatherstrip rarely fits properly along the top of the glass, especially in front. It has a metal reinforcement rib inside the rubber that can be bent outward to fit the weatherstrip tight to the glass. The bottom line is the adjustment, requiring a balancing act with all factors. Sometimes compromises are necessary for the window to fit and seal properly.

The toughest factor to overcome is weatherstrip density. Unfortunately, repro weatherstrips don't match originals. They are denser, making it difficult- if not impossible-to seal the windows. If the windows seal, they're usually so tight against the dense weatherstrips, window movement is restricted. Sometimes, the windows won't even move unless the door is open. We've tried lubing the weatherstrips with silicone to aid in window movement, but it only helps temporarily.

GM has discontinued the original weatherstrips, making reproductions the only option. Hopefully, repro weatherstrips will be reformulated for correct density. Until then, we'll open the door to close our windows fully.

Remember to look at window positioning before closing the door. This isn't a job for the timid, but with patience and a keen eye, the adjustments can be done with rewarding results.


Corvette America
Reedsville, PA



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