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1984 - 1993 Corvette: Service Bulletin: Rear Lift Window Hard to Open/Hinge Loose to Glass

Model and Year: 1984-1993 Corvette
Source: Chevrolet Service Bulletin
Bulletin Number: 93-131-10


Some owners may comment regarding rear lift window that sticks in the down position or the hinge is loose to the glass.


Reinstall and rebond the hinge plate to the glass using the following procedure.


MAXXUS tm UNIVERSAL BONDER and CHEMLOK (R) PRIMER AP134 can be purchased locally, or they may be purchased by calling *Lord Corporation on 1-800-458-0434 EXT.3541.


1. With the lift window release button depressed, from inside the vehicle push upward to open the window. Note: It may be necessary to pry forward carefully on the glass with a plastic object to get the glass to release.

2. Remove roof panel.

3. Support the lift window and remove struts from the vehicle by prying out on the retainers while pulling on the strut.

4. Loosen the two spanner nuts on the glass using *Kent Moore door and quarter window roller nut socket P/N J22055 and push the glass forward to align the glass in the opening. Apply three pieces of tape to the glass for alignment of the hinge plate to the glass after the glass is removed from the vehicle. Cut the tape spanning the glass and hinge plate as shown in Figure 1.

5. With a marker, outline both hinge attachments to the body for alignment purposes later.

6. Remove the right and left rear compartment front trim panel partially to gain access to the hinge nuts.

7. On ZR1 vehicles with the high mounted stop lamp, remove the wire connector.

8. Peel back and reposition noise control patch and remove the four retaining nuts, and with the aid of a helper, remove the glass from the vehicle.

9. Remove spanner nuts and hinge from glass, clean butyl and adhesive off hinge and glass. NOTE: For ease of butyl removal use a small ball of butyl and dab the butyl.

10. Clean both surfaces with 3M general purpose adhesive cleaner and clean with glass cleaner.

11. Prime glass with CHEMLOK (R) primer P/N AP 134. Prime the whole area above the tape line.

IMPORTANT: After priming glass let the glass sit for 30 minutes at room temperature.

12. While primer is drying, Sand the painted surface of the hinge plate with 120 grit sand paper to remove the primer (SEE FIGURE 2). Clean hinge surface with glass cleaner and let dry.

13. Apply 1/8" butyl around the perimeter of the hinge plate as shown in Figure 3, leaving two one inch gaps at the bottom of the hinge plate. Reinstall the two rubber bumpers to the hinge plate as shown in (FIGURE 3).

14. Apply MAXXUS tm UNIVERSAL BONDER to the hinge plate as shown in FIGURE 3 and 4. Follow manufacturer’s instructions on the adhesive package for mixing and dispensing. As an aid after mixing the contents by hand, the round plastic dowel may be used to push the material from end to end.

NOTICE: Adhesive only has a 15 to 30 minute work time.

15. Reinstall hinge plate to the lift glass and align the plate to the glass using the tape that was installed in Step 4. Tighten the spanner nuts to 1.5 N.m (1 3 lbs. in.).

16. Let the glass stand at room temperature over night.

17. With the aid of a helper, position lift window to vehicle and support. Using the marks from step five, align the hinge plate to the body and torque the hinge to body retaining nuts to 27 N.m (20 lbs. ft.).

18. Reinstall the struts and check operation of the lift glass. Reinstall the front trim panel and roof panel.

*We believe these sources and their equipment to be reliable. There may be additional manufacturers of such equipment. General Motors does not endorse, indicate any preference for or assume any responsibility for the products or equipment from these firms or for any such items which may be available for other sources.


NOTE: While the above procedure and materials are correct for vehicles from l884-1993 the labor operation and time allowance only pertains to vehicles in the warranty period.


General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.
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