Removal Procedure
- Remove all related panels and components.
- Visually inspect and repair as much of the damage as possible to factory specifications.
- Remove all sealers and anti-corrosion materials as necessary.
- Apply 25 mm (1 in) wide tape on the lower rail outer panel following the contour of the cowl.
- Cut the outer panel along the forward edge of the tape.
- Drill out all the factory welds attaching the outer panel to the rail inner panel. Do not drill through the inner panel.
- Remove the rail outer panel.
- Measure 75 mm (3 in) forward of the engine mount brace located inside the right rail (1) and mark a line.
- Drill a 3 mm (1/8 in) hole on the line.
- Use the hole as a guide and mark a line around the outside of the rail.
- Cut the rail along the marked line and remove the damaged portion of the rail.
Important: Sectioning of the lower rail does NOT require removal of the powertrain.
Important: Welds on the engine cradle mounting bracket must also be drilled out to remove the outer panel.
Installation Procedure
- Locate and drill out factory welds attaching the outer panel to the inner panel on the service part. Drill through one layer ONLY at the front half of the rail.
- Use an air chisel to separate the inner (1) from the outer rail (2).
- Remove the outer panel and trim off the rear edge that welds to the cowl panel.
- Measure 45 mm (1 3/4 in) on the right side rail, forward to the engine mount brace. This is 30 mm (1 ¼ in) less than the original sectioning cut.
- Drill a 3 mm (1/8 in) hole on the line.
- Use the hole as a guide to mark a line around the rail.
- Cut the service part along the marked line and discard the unused section.
- Cut a 3 mm (1/8 in) gap approximately 30 mm (1 1/4 in) deep along the corners of the inner rail to create tabs.
- Step the tabs inward to allow the service part section to fit inside the original rail.
- Drill 5 holes for plug welding along the overlap approximately 13 mm (1/4 in) from the sectioning cut.
- Use three-dimensional measuring to position the modified service part inside the original rail.
- Drill 3 holes in the rail outer panel in front of the cowl.
- Position the outer panel to check for proper fit and alignment.
- Stitch weld along the entire joint.
- Plug weld all holes drilled during the removal process.
- Clean and prepare all welded surfaces.
- Apply approved anti-corrosion primer.
- Apply the sealers and finish as necessary.
- Install all related panels and components.
Important: Welds on the engine cradle mounting bracket must also be drilled out to remove outer panel.
Important: Crush zones vary from left rail (1) to right rail (2). Remove the outer rail at the factory seams to section the inner rail.
Be certain the engine cradle mounting location is in the proper position. Align and hand tighten bolt.
When stitch welding, make 25 mm (1 in) welds along the seam with 25 mm (1 in) gaps between. Complete the stitch weld.
Important: Prior to refinishing, refer to the publication GM 4901M-2000 GM Approved Refinish Materials for recommended products. Do not combine paint systems. Refer to paint manufacturer's recommendations.
