Adhesive Installation of Liftgate Windows
- Use a urethane adhesive systems which meet GM Specification GM 3651G.
- Remove all mounds or loose pieces of urethane adhesive from the pinch-weld area.
- If the original window is being reused, remove all but approximately 2 mm (3/64 in) of the existing bead of urethane adhesive from the pinch-weld flange surface by using a clean utility knife or razor blade scraper.
- Inspect for any of the following conditions in order to help prevent future breakage of the window:
- High weld
- Solder spots
- Hardened sealer
- Any other obstruction or irregularity in the pinch-weld flange
- After repairing the opening as indicated, perform the following steps:
- Remove all traces of broken glass from the outer cowl panel, seats, floor and defroster ducts.
- Clean around the edge of the inside surface of the window with a 50/50 mixture of isopropyl alcohol and water by volume on a dampened lint free cloth.
- Verify all primers and urethane adhesive are within expiration dates.
- Shake the pinch-weld primer black for at least 1 minute.
- Use a new dauber in order to apply the primer to the surface of the pinch-weld flange.
- Allow the pinch-weld primer to dry for approximately 10 minutes.
- With an assistant, dry fit the window (2) to the opening in order to determine the correct position.
- Ensure the window locator pins (1) are positioned into the locator slots in the pinch-weld flange.
- Use masking tape to mark the locations of the window in the opening.
- Cut the masking in the center and remove the window from the opening.
- Use a new dauber in order to apply glass prep clear to the area approximately 18 mm (0.71 in) around the entire perimeter of the window inner surface.
Immediately wipe the glass primed area using a clean, lint-free cloth.
- Apply a second coat of the glass prep clear to the same area of the glass.
- Shake the glass primer black for at least 1 minute.
- Use a new dauber in order to apply the glass primer black to the same areas (2) that glass prep clear was applied.
- Allow the glass primer to dry for approximately 10 minutes.
- Cut the applicator nozzle in order to provide a bead of 12.7 mm (1/2 in) wide and 12.7 mm (1/2 in) high.
- Use a cartridge-type caulking gun in order to apply a smooth, continuous bead of urethane adhesive.
- Use the edge of the window as a guide for the nozzle in order to apply the urethane adhesive (1) to the inner surface of the window (3).
- With an assistant, place the window (2) in the opening.
- Align the masking tape with the lines on the window and the body.
- Press firmly around the entire periphery of the window in order to wet-out the urethane bead.
- Tape the window to the body in order to minimize movement until the urethane adhesive cures.
- Clean any excess urethane adhesive from the body.
- Use a soft spray of warm water in order to immediately water test the window.
- Inspect the window for leaks.
- If any leaks are found, use a plastic paddle in order to apply extra urethane adhesive at the leak point.
- Retest the window for leaks.
- For the moisture-curing type of urethane adhesive, allow a minimum of 6 hours at 21°C (70°F) or greater and with at least 30 percent relative humidity. Allow at least 24 hours for the complete curing of the urethane adhesive.
- For the chemical-curing type of urethane adhesive, allow a minimum of 1 hour.
- Maintain the following conditions in order to properly cure the urethane adhesive:
- Partially lower a door window in order to prevent pressure buildups when closing doors before the urethane adhesive cures.
- Do not drive the vehicle until the urethane adhesive is cured. Refer to the above curing times.
- Do not use compressed air in order to dry the urethane adhesive.
- Complete the window installation.
Refer to Glass and Sheet Metal Handling Warning .
If corrosion of the pinch-weld flange is present or if sheet metal repairs or replacements are required, the pinch-weld flange must be refinished in order to restore the bonding area strength. If paint repairs are required, mask the flange bonding area prior to applying the color coat in order to provide a clean primer only surface. Materials such as BASF DE15®, DuPont 2610®, Sherwin-Williams PSE 4600 and NP70® and Martin-Semour 5120 and 5130® PPG DP90LF SPIES/HECKER 3688/8590 - 3688/5150 - 4070/5090 STANDOX 11158/13320 - 14653/14980 products are approved for this application.
Refer to Window Retention Warning .
Failure to prep the area prior to the application of primer may cause insufficient bonding of urethane adhesive. Insufficient bonding of urethane adhesive may allow unrestrained occupants to be ejected from the vehicle resulting in personal injury.
Do not apply the black primer to the existing bead of the urethane adhesive on the pinch-weld flange. Apply the primer only to nicks, scratches or the primed surfaces.
Use care when applying glass prep clear on the window. This primer dries almost instantly, and may stain the viewing area of the window if not applied evenly.
The glass primer black is effective up to 8 hours after applying it to the glass. The primed surface of the glass must be kept clean.
There are window locating pins (1), one in each upper corner of the window. If the window locator pins are cut, it will be necessary to tape the window in place.
To prevent damage to the window due to objects impacting an exposed edge, upon installation, the window must rest 1 mm (0.040 in) below the surface of the sheet metal.
Do not direct a hard stream of high pressure water to the freshly applied urethane adhesive.
Insufficient curing of urethane adhesive may allow unrestrained occupants to be ejected from the vehicle resulting in personal injury.
Do NOT physically disturb the repair area until after these minimum times have elapsed.