For 1990-2009 cars

### Removal Procedure

This assembly is available as part of the rear side rail underbody assembly. If only the inner rocker panel extension is required, remove the extension from the complete assembly before installation.

Caution: Refer to Approved Equipment for Collision Repair Caution in the Preface section.

1. Disable the SIR system. Refer to SIR Disabling and Enabling .
2. Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection .
3. Remove all related panels and components.
4. Repair as much of the damaged area as possible. Refer to Dimensions - Body .
5. Remove the sealers and 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 inner rocker panel extension.

6. Locate and drill out all the necessary factory welds.
7. Remove the inner rocker panel extension.

### Installation Procedure

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.

1. Drill 8-mm (5/16-in) plug weld holes in the service part as necessary in the corresponding locations noted on the original panel.
2. Prepare all mating surfaces for welding as necessary.
3. Apply GM-approved Weld-Thru Coating or equivalent to all mating surfaces. Refer to Anti-Corrosion Treatment and Repair .
4. Position the inner rocker panel extension.
5. Plug weld accordingly.
6. Clean and prepare all of the welded surfaces.
7. Install all of the related panels and components.
8. Apply the sealers and anti-corrosion materials to the repair area, as necessary. Refer to Anti-Corrosion Treatment and Repair .
9. Paint the repaired area. Refer to Basecoat/Clearcoat Paint Systems .
10. Connect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection .
11. Enable the SIR system. Refer to SIR Disabling and Enabling .