FLOOR PAN OIL CANNING INSTALL BETA BRACE MATERIAL

MODELS AFFECTED: 1986-90 RIVIERA

Some 1986-1990 Rivieras may experience a floor pan oil canning (popping noise) in the area of the driver or passenger seat assembly in response to torsional inputs to the body during vehicle operation (driveways, twist course, vehicle turns, or while braking, etc.). This condition may be caused by insufficient stiffness to the area of the floor pan between the number 2 and number 3 bars and between the inboard attachment flange of the longitudinal rail and center tunnel surface.

To repair this condition use the following procedure:

1. Remove the left and right front seat assemblies.

2. Remove the left and right carpet retainer molding from the door opening.

3. Remove the rear seat lower cushion assembly.

4. Fold floor carpet inboard to the center tunnel to expose the floor pan area.

5. Remove insulation material from between the number 2 and number 3 floor pan bars (seat attachment points).

6. Obtain two 180mm wide x 160mm long sections of the beta brace structural reinforcement material, P/N 20740401, from GMSPO.

7. Prepare the floor pan for the beta brace material installation:

A. Clean the floor pan surface in between the floor pan bars; center tunnel and outboard longitudinal depression. Refer to Figure 1. Remove any dirt, grease, or oil.

B. Utilizing a standard hot air gun (500-700 DEG F) apply heat to the surface of the floor pan in the area previously cleaned.

8. Locate the beta brace patch as follows:

A. Butt the forward edge of the patch against the rear edge of the number 2 and number 3 bar weld flanges. Refer to Figure 1.

B. The inboard edge of the patch will be located at the lower surface of the center tunnel radius.

C. The rear edge of the patch will locate next to the body wiring harness conduit assembly.

D. Apply heat (by means of the air gun) directly to the surface of the beta brace patch for approximately 12-14 minutes.

E. Remove the heat source and allow the material to cure for approximately 30-45 minutes.

9. Following Completion of the Material Curing (Hardening):

A. Install insulation material between the number 2 and number 3 floor pan bars.

B. Position floor carpet assembly in the original position.

C. Install rear seat lower cushion assembly.

D. Install left and right carpet retainer molding assemblies in the lower door openings.

E. Install left and right seat assemblies.

Parts are currently available from GMSPO.

WARRANTY INFORMATION:

Labor Operation: T6447 Labor Hours: 1.7 hours

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.