Removal Procedure
Important: The front upper rail is serviced as two components: inner (1) and outer
(3) panels. The outer panel is serviced as a sub-assembly which includes an
inner reinforcement (2). After removing the outer rail has been removed,
the inner rail is completely accessible and can be serviced at the factory
seams.
Sectioning of the front upper rails is not recommended.
- Remove all related panels
and components.
- Remove sealers and anti-corrosion materials as necessary.
- Locate, mark, and drill out all factory welds attaching the outer
rail.
- Remove the damaged outer rail (3).
- Locate, mark, and drill out the welds attaching the inner rail
(1).
- Remove the damaged inner rail.
Installation Procedure
- Prepare the mating surfaces
as necessary.
- Drill 8 mm (5/16 in) plug weld holes as necessary
in the locations noted from the original panels.
Important: If original locations are damaged beyond recognition, locate holes for
plug welding 40 mm (1½ in) apart.
- Temporarily position the inner and outer rails on the vehicle.
- Using three-dimensional measuring equipment, locate and mark front
fender mounting bolt holes in the outer rail.
- Drill 5.5 mm (7/32 in) holes for self-tapping bolts
as marked.
- When the service panels are correctly positioned, remove the outer
panel and plug weld the inner panel as necessary.
- Reposition the outer rail with frequent measurements to ensure
proper fit and alignment.
- Plug weld accordingly.
- Clean and prepare all welded surfaces.
Important: Prior to refinishing, refer to GM 4901MD-99 Refinish Manual for
recommended products. Do not combine paint systems. Refer to paint manufacturer's
recommendations.
- Prime with a two-part catalyzed primer.
- Apply sealers and anti-corrosion materials as necessary.
- Install all related panels and components.