See Figures 1, 2 and 3
Bonded windshields require special tools and special removal procedures to be performed to ensure the windshield will be removed without being broken. For this reason we recommend that you refer all removal and installation to a qualified technician.
When replacing a cracked windshield, it is important that the cause of the crack be determined and the condition corrected, before a new glass is installed. The cause of the crack may be an obstruction or a high spot somewhere around the flange of the opening; cracking may not occur until pressure from the high spot or obstruction becomes particularly high due to winds, extremes of temperature or rough terrain.
When a windshield is broken, the glass may have already have fallen or been removed from the weatherstrip. Often, however, it is necessary to remove a cracked or otherwise imperfect windshield that is still intact. In this case, it is a good practice to crisscross the glass with strips of masking tape before removing it; this will help hold the glass together and minimize the risk of injury.
If a crack extends to the edge of the glass, mark the point where the crack meets the weather strip. (Use a piece of chalk to mark the point on the cab, next to the weatherstrip.) Later, examining the window flange for a cause of the crack which started at the point marked.
The higher the temperature of the work area, the more pliable the weather strip will be. The more pliable the weather strip, the more easily the windshield can be removed.
There are two methods of windshield removal, depending on the method of windshield replacement chosen. When using the short method of installation, it is important to cut the glass from the urethane adhesive as close to the glass as possible. This is due to the fact that the urethane adhesive will be used to provide a base for the replacement windshield.
When using the extended method of windshield replacement, all the urethane adhesive must be removed from the pinchweld flange so, the process of cutting the window from the adhesive is less critical.
REMOVAL & INSTALLATION
The following procedure may be used for front and rear glass and requires the use of the Urethane Glass Sealant Remover (hot knife) tool No. J-24709-1 or equivalent, the Glass Sealant Remover Knife tool No. J-24402-A or equivalent.
- Place the protective covering around the area where the glass will be removed.
- Remove the windshield wiper arms, the cowl vent grille, the windshield supports, the rear view mirror and the interior garnish moldings.
If equipped with a radio antenna, embedded in the windshield, disconnect the cable connector from the windshield.
- Remove the exterior reveal molding and glass supports from the windshield.
- Using the Urethane Glass Sealant Remover (hot knife) tool No. J-24709-1 or equivalent, and the Glass Sealant Remover Knife tool No. J-24402-A or equivalent, cut the windshield from the urethane adhesive. If the short method of glass replacement is to be used, keep the knife as close to the glass as possible in order to leave a base for the replacement glass.
- With the help of an assistant, remove the glass.
- If the original glass is to be reinstalled, place it on a protected bench or a holding or holding fixture. Remove any remaining adhesive with a razor blade or a sharp scraper. Any remaining traces of adhesive material can be removed with denatured alcohol or lacquer thinner.
When cleaning the windshield glass, avoid contacting the edge of the plastic laminate material (on the edge of the glass) with a volatile cleaner. Contact may cause discoloration and deterioration of the plastic laminate. DO NOT use a petroleum based solvent such as gasoline or kerosene; the presence of oil will prevent the adhesion of new material.
Inspection of the windshield opening, the weather strip and the glass may reveal the cause of a broken windshield; this can help prevent future breakage. If there is no apparent cause of breakage, the weatherstrip should be removed from the flange and the flange inspected. Look for high weld or solder spots, hardened spot welds sealer, or any other obstruction or irregularity in the flange. Check the weatherstrip for irregularities or obstructions in it.
Check the windshield to be installed to make sure that it does not have chipped edges. Chipped edges can be ground off, restoring a smooth edge to the glass and minimizing concentrations of pressure that cause breakage. Remove no more than necessary, in an effort to maintain the original shape of the glass and the proper clearance between it and the flange of the opening.
To replace a urethane adhered windshield, a GM Adhesive Service Kit contains some of the materials needed and should be used to ensure the original integrity of the windshield design. Materials in this kit include:
- One tube of adhesive material.
- One dispensing nozzle.
- Steel music wire.
- Rubber cleaner.
- Rubber Primer.
- Pinchweld primer.
- Blackout primer.
- Filler strip (for use on windshield installations of vehicles equipped with an embedded windshield antenna).
- Primer applicators.
Other materials required for windshield installation which are not included in the service kit, are:
- Using masking tape, apply the tape across the windshield pillar-to-windshield opening, then cut the tape and remove the windshield.
- Using an alcohol dampened cloth, clean the metal flange surrounding the windshield opening. Allow the alcohol to air dry.
- Using the pinchweld primer, found in the service kit, apply it to the pinchweld area. DO NOT let any of the primer touch the exposed paint for damage to the finish may occur; allow five minutes for the primer to dry.
- Cut the tip of the adhesive cartridge approximately 3 / 15 inch (5mm) from the end of the tip.
- Apply the adhesive first in and around the spacer blocks. Apply a smooth continuous bead of adhesive into the gap between the glass edge and the sheet metal. Use a flat bladed tool to paddle the material into position if necessary. Be sure that the adhesive contacts the entire edge of the glass and extends to fill the gap between the glass and the solidified urethane base.
- With the aid of a helper, position the windshield on the filler strips against the two support spacers.
The vehicle should not be driven and should remain at room temperature for six hours to allow the adhesive to cure.
- Spray a mist of water onto the urethane. Water will assist in the curing process. Dry the area where the reveal molding will contact the body and glass.
- Install new reveal moldings. Remove the protective tape covering the butyl adhesive on the underside of the molding. Push the molding caps onto each end of one of the reveal moldings. Press the lip of the molding into the urethane adhesive while holding it against the edge of the windshield. Take care to seat the molding in the corners. The lip must fully contact the adhesive and the gap must b