FRT. DOOR GLASS PERFORMANCE REPAIRS AND DIAGNOSIS

Models Affected: 1987 - 1988 BONNEVILLE

CORRECTIVE ACTION FOR WINDOW SYSTEMS:

1. Misadjusted glass is the number one cause of most customer comments regarding window operation. Front and rear guides not parallel to one another, can cause a bending moment force at the rear glass guide which in turn causes the PIN GUIDE TO UNLATCH AND REAR OF GLASS TO BE UNATTACHED. Indicators are a rocking motion of glass during window travel, top edge of glass not parallel with door header and/or rear pin guide becoming visible from beneath rubber run channel.

Corrective Action - Adjust as follows:

a. Remove door trim panel and water deflector, per 1988 Body Service Manual, Section 5C.

b. Loosen upper and lower glass run channel retainer screws (See Figure 1.)

c. Cycle glass to full up position into door upper frame.

d. Grasp door glass and move glass fully up and rearward.

e. Tighten previously loosely installed upper and lower glass run channel screws to specified torque of 9.0 to 12.0 N.m (80-106 in. lb.).

f. Cycle glass down and to full up position to check operation of glass.

NOTICE: When glass is in full down position, the top of the door glass should be flush to no more than 7 to 10 mm (3/8") (See Figure 2) higher than beltline molding. The position of the regulator guide to tape determines down travel position of glass in relation to door beltline molding. DO NOT LOWER REGULATOR as this may cause the window to drop down too far, causing the front pin guide to drop below the front retainer, or cause the guide block to move forward out of the glass lower sash (if the regulator isn't equipped with an up travel stop).

2. Regulator guide block overtravel. A regulator guide block that does not stop at top of regulator radius, but continues on over the top and exits the sash (See Figure 3) at the front of sash, can cause the window to drop to bottom of door. Usually pin guides are intact, and the front and rear glass is in the tracks at bottom of door.

3. Hot Melt Window Sash Separation from Glass: All 1987 Bonneville models built before VIN 480001 have a hot melt glue on lower sash. These glasses are either 4 or 5mm thick. If unsure of glass thickness, use a micrometer and measure.

5mm = .20" 4mm = .16"

See flow chart, Figure 4 and 5 for proper repair kit. See Figures 6 thru 8 for kit part make up.

5. Clicking sound heard during window travel, approximately 2-3 inches of full up position on vehicles riveted on lower sash.

All 1987 Bonneville models built after VIN 480000 have a rivet retained door glass sash channel. The subject door glasses should be serviced using the factory installed method. Refer to Section 5C of the 1988 Body Service Manual (NOTICE: SINCE THE MANUAL WAS PUBLISHED, THE RIVET, PART NUMBER 9441725, LISTED ON 5C-21 IS OUTDATED. USE ONLY THE NEW EXPANDABLE RIVET, PART NUMBER 20743322, WHICH IS IN THE SERVICE KIT). See Figure 6 and 7, Flow Charts, and Figures 6 thru 8 for proper repair kit usage.

6. Glass Pin Guide Repairs - it is recommended to replace both front and rear pin guide clips if either one has disengaged from a run channel. Make sure that the new clips are properly secured thru the glass. All pin guides in repair kits are of the solid pin type (See Figure 9), black in color. Each kit will contain a front glass run channel to ensure against a distorted or damaged existing channel.

NOTICE: If any difficulty is encountered during installation of pin guides, check location of holes in glass. See Figures 10 and 11. If holes are mislocated, replace the glass.

CONTRIBUTORS TO WINDOW SYSTEM FAILURE

1. DO NOT - Elongate the door inner panel screw hole to move the lower portion of the front window guide channel rearward. If this is done, it would move the glass rearward during it's down cycle, causing the glass to pivot at the bottom of the rear run channel; resulting in the top of the glass moving forward, disengaging the rear pin guide from the glass.

2. DO - Check for correct usage.

3. DO - If the power window operates slowly and the window has had a repetitive pin guide failure.

a. Remove the window regulator, per the 1987 Body Service Manual Section 5C.

CAUTION:

Tape the edges of the door inner panel access holes with cloth back tape to prevent personal injury.

b. Reach thru the access holes with both hands and slide the glass full travel up and down to determine if the glass slides freely or binds. If a bind condition is encountered, investigate cause, run channel alignment or distortion, mirror patch insulator interference, etc.

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.