Laminated Steels - General Information and Specific Repair Procedures for Lower Rail Replacement and Front Inner Hinge Pillar Body Replacement

Laminated steel consists of three layers of material: two layers of mild steel with a layer of "visco-elastic" material between them. This "sandwich" of material layers provides better sound absorbing properties than regular, non-laminated materials.

Laminated steel is being used on the above listed vehicles to enhance the acoustic performance of these vehicles. Currently, the front dash panel of these vehicles is made from laminated steel.

This material is very different than standard steel applications. Because of these differences, it requires different repair procedures to be used when replacing components that attach directly to the laminated steel surfaces. Those components are typically structural rails, front wheelhouse/shock towers and front body hinge pillar inner panels. Depending on the design and build of the vehicle, though, some of the components may not attach directly to the laminated steel surface. Components that do not attach directly to the laminated steel surface may be attached in the normal manner.

Refer to GM Service Information for the above-listed vehicles for specific procedures related to the components that attach to laminated steels. The procedure below has recently been added to SI. Additional procedures are currently being developed and Service Manual Update bulletins will be published to inform dealers of this new information.

The front of the dash panel is formed from laminated steel. This steel is constructed by bonding 2 pieces of cold rolled steel (1) with a viscoelastic layer of adhesive (2). Metal inert gas (MIG) welding laminated steel does not meet GM Corporate standards for structural integrity. As an alternative, all factory welds will be replaced by using the rivet and adhesive bond method described in the installation portion of this procedure. The rivet and adhesive bond method must only be used in the areas as described in this procedure.

Important: Failure to follow this procedure will compromise the structural integrity of the vehicle.

Removal Procedure

Caution: Refer to Approved Equipment for Collision Repair Caution in Cautions and Notices.

Caution: Refer to Foam Sound Deadeners Caution in Cautions and Notices.

1. Disable the SIR system. Refer to SIR Disabling and Enabling Zones.
2. Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnect/Connect Procedure.

Caution: Sectioning should be performed only in the recommended areas. Failure to do so may compromise the structural integrity of the vehicle and cause personal injury if the vehicle is in a collision.

3. Remove all related panels and components.
4. Repair as much of the damage as possible.
5. Remove the sealers and the anti-corrosion materials from the repair area, as necessary. Refer to Anti-Corrosion Treatment and Repair.

Important: Note the number and location of the factory welds for installation of the full rail service part.

6. Remove the front wheelhouse assembly. Refer to Wheelhouse Replacement-Front.




Important: Drill through the rail flange only. Do NOT drill into the dash panel or the inner reinforcements.

7. Using an 7-mm (17/64-in) spot weld remover, locate and drill out the factory welds on the weld flange connecting the lower rail to the dash panel.



8. Using an 8-mm (5/16-in) spot weld remover, locate and drill out the factory welds on the weld flange connecting the lower rail to the inner hinge pillar.



9. From the passenger compartment, locate the remaining factory welds which join the floor, the front of the dash, and the frame rail. Using an 8-mm (5/16-in) spot weld remover, drill out these welds.




Important: Do NOT remove the rail inner reinforcement from the vehicle.

10. Locate and drill out the factory welds between the rail inner reinforcement and the rail. Drill through the reinforcement only. Do NOT drill through the rail and the floor.



11. Locate and drill out the remaining factory welds on the rail.



12. Separate the floor pan reinforcement vertical flanges from the inside of the lower rails. Do NOT damage the flanges.

Important: Note that the flanges overlap the rails.

13. Drill out the factory welds along the lower flanges on the floor pan reinforcement. Use an 8-mm (5/16-in) drill bit.
14. Turn the lower flanges down at an angle away from the rail.
15. Drill out the remaining factory welds on the rail. Drill out and remove the lower portion of the rail at the wheelhouse.
16. With a flat chisel, loosen the adhesive between the floor pan and the lower rail by prying the rail away from the floor. Do NOT damage the floor.



17. Remove the full rail.
18. Turn the vertical flange forward to be welded to the new rail.

Installation Procedure

1. Position the service rail to the vehicle using three-dimensional measuring equipment.
2. Clamp the rail in place.



3. Using a 7-mm (17/64-in) bit, drill the rivet attachment holes through the service rail and the dash panel in the exact locations as noted from the factory rail.



4. From the passenger compartment side of the vehicle, using a 7-mm (17/64-in) bit, drill the rivet attachment hole through the service rail using the existing 8-mm (5/16-in) holes in the dash panel as alignment marks.
5. Remove the service rail.

Important: If the location of the original plug weld holes cannot be determined, space the plug weld holes every 40 mm (1.5 in) apart.

6. Drill 8-mm (5/16-in) plug weld holes in the service rail, as necessary, in the remaining locations noted from the original rail.
7. Prepare the plug weld mating surfaces, as necessary.
8. Apply 3M® Weld-Thru Coating P/N 05913, or equivalent, to the plug weld mating surfaces.



9. Prepare the bond mating areas by grinding the body mating and the service part flanges to bare steel. Do NOT damage the corners or thin the metal during the grinding process.
10. Clean the mating surfaces.




Important: The adhesive has a 40-50 minute working time. Do NOT allow the adhesive to cure prior to installing the service rail.

11. Apply a 3-6 mm (1/8 to 1/4 in) bead of metal panel bonding adhesive, P/N 12378567 (Canadian P/N 88901675), or equivalent, to both of the mating surfaces.



12. Using a small acid brush, spread a coat of adhesive to both of the mating surfaces. Cover all of the bare metal to ensure corrosion protection.



13. Apply a 3-6 mm (1/8 to 1/4 in) bead of metal panel bonding adhesive, P/N 12378567 (Canadian P/N 88901675), or equivalent, to the mating surface of the service rail.




Important: Do NOT pull the rail off of the dash after adhesion. To align the parts, slide the rail against the front of the dash.

14. Position the service rail to the vehicle using three-dimensional measuring equipment.
15. Clamp the rail in place.




Important: Verify proper positioning of the service rail prior to riveting and welding.

16. Install the rivets so that the rivet head contacts the passenger compartment side of the dash.



17. Install the rivets so that the rivet head contacts the rail.
18. Remove the excess adhesive from the rail area.
19. Plug weld the remaining holes accordingly.
20. Clean and prepare all of the welded surfaces.
21. Install the front wheelhouse assembly. Refer to Wheelhouse Replacement--Front.
22. Apply the sealers and anti-corrosion materials to the repaired area, as necessary. Refer to Anti-Corrosion Treatment and Repair.
23. Paint the repaired area. Refer to Basecoat/Clearcoat Paint Systems.
24. Install all of the related panels and components.
25. Connect the negative battery cable. Refer to Battery Negative Cable Disconnect/Connect Procedure.
26. Enable the SIR system. Refer to SIR Disabling and Enabling Zones.

Important: Failure to follow this procedure will compromise the structural integrity of the vehicle.

The front of the dash panel and plenum lower are formed from laminated steel. This steel is constructed by bonding 2 pieces of cold rolled steel with a viscosities layer of adhesive. MIG welding laminated steel does not meet GM Corporate standards for structural integrity. As an alternative, all factory welds may be replaced by using the rivet and adhesive bond method described in the installation portion of this procedure. The rivet and adhesive bond method must only be used in the areas described in this procedure.

Removal Procedure

Caution: Refer to Approved Equipment for Collision Repair Caution in Cautions and Notices.

1. Disable the SIR system. Refer to SIR Disabling and Enabling Zones in SIR.
2. Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnect/Connect Procedure in Engine Electrical.



3. Remove the sealers and anti-corrosion materials from the repair area, as necessary. Refer to Anti-Corrosion Treatment and Repair in Paint/Coatings.
4. Visually inspect the damaged area. Repair as much of the damage as possible. Refer to Dimensions - Body.



5. Using an 8 mm (5/16 in) spot weld remover, locate and drill out the factory welds on the weld flange connecting the front inner hinge pillar to the dash panel and the rail extension.




Important: Note the number and location of welds for installation of the front inner hinge pillar.

6. Locate and drill out all remaining factory welds.



7. Remove the front inner hinge pillar from the vehicle.

Installation Procedure

1. Position the service front inner hinge pillar in the vehicle using 3-dimensional measuring equipment. Clamp the front inner hinge pillar in place.



2. Using a 7 mm (17/64 in) bit, drill the rivet attachment holes into the service hinge pillar through the dash and the lower rail extension in the locations as noted from the factory front inner hinge pillar.



3. Remove the service front inner hinge pillar.

Important: If the location of the original plug weld holes can not be determined, space the plug weld holes every 40 mm (1 1/2 in) apart.

4. Drill 8 mm (5/16 in) plug weld holes as necessary in the locations noted from the original assembly.
5. Prepare the MIG weld mating surfaces as necessary.
6. Apply 3M Weld-Thru Coating, P/N 05916, or equivalent, to all MIG weld mating surfaces.




Important: Do not damage the corners or thin the metal during the grinding process.

7. Prepare the bonding mating areas by grinding to bare steel the surface of the dash panel and the service front inner hinge pillar flanges.



8. Apply a 3-6 mm (1/8-1/4 in) bead of metal panel bonding adhesive, P/N 12378567 (Canadian P/N 88901675), or equivalent, to the mating surfaces of the dash panel and the front inner hinge pillar service panel.



9. Using a small acid brush, spread a coating of adhesive on the mating surfaces. Cover all of the bare metal to ensure corrosion protection.

Important: Do not pull the front inner hinge pillar off of the dash after adhesion. To align the parts, slide the front inner hinge pillar against the dash panel.

10. Position the service front inner hinge pillar to the vehicle using 3-dimensional measuring equipment. Clamp the front inner hinge pillar in place.




Important: Verify the proper positioning of the service front inner hinge pillar prior to riveting and welding.

11. Install the 14 mm (17/32 in) long rivets so that the rivet head contacts the rail extension and the front of the dash panel.



12. Remove the excess adhesive from the front inner hinge pillar bond rivet area.



13. Plug weld accordingly.
14. Clean and prepare all of the welded surfaces.
15. Apply the sealers and anti-corrosion materials to the repair area, as necessary. Refer to Anti-Corrosion Treatment and Repair in Paint/Coatings.
16. Paint the repaired area. Refer to Basecoat/Clearcoat Paint Systems in Paint/Coatings.
17. Install all related panels and components.
18. Connect the negative battery cable. Refer to Battery Negative Cable Disconnect/Connect Procedure in Engine Electrical.
19. Enable the SIR system. Refer to SIR Disabling and Enabling Zones in SIR.

Important:  These kits contain a rail or panel, an instruction sheet and rivets. The rivets and instruction sheet are common among the kits, but the rail or panel is specific to each kit.