Filler Thickness and Corrosion Protection on a Galvanized Sliding Door
A 2018 Chrysler Pacifica right sliding door has a 300 mm dent across the character line. The paint is cracked and the e-coat is exposed at the crown, but no bare steel is visible. The technician grinds the damaged area to bare steel with 36-grit paper, pulls the dent, applies polyester body filler up to 6 mm thick, blocks it, and applies primer and paint. He does not apply seam sealer or cavity wax, explaining that the door is galvanized. The OEM procedure allows a maximum filler thickness of 3 mm and requires corrosion protection on bare metal and behind repaired areas. The door has a factory seam at the beltline and drain holes at the bottom. The customer is picking up the vehicle tomorrow and the shop wants to avoid replacing the door skin.
1. Evaluate the surface preparation and filler application. What is wrong and what risk does it create?
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Grinding to bare steel with 36-grit is too aggressive and unnecessary. It removes the protective coating and creates deep scratches that can trap moisture and show through the finish. Filler applied over bare steel without the specified primer can lose adhesion and corrode from beneath. The 6 mm filler thickness exceeds the OEM maximum of 3 mm and can shrink, crack, or telegraph the repair. The risks include paint failure, corrosion, a visible repair, and reduced panel durability. The technician should remove paint only to the e-coat or to the level specified by the OEM, use the recommended primer, and keep filler within the published limit. If the dent cannot be brought within 3 mm, the door skin should be replaced rather than bridged with excessive filler.
2. What corrosion protection and seam sealing steps should be performed?
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After metal finishing, apply the OEM-approved primer to bare or exposed areas, then apply filler within the allowed thickness and finish with the specified primer system. Apply seam sealer to the factory seam at the beltline and to any other opened seam, matching the original appearance and not blocking drain holes. Apply cavity wax or inner-panel corrosion protection behind the repaired area and inside the door cavity. Use OEM-approved materials and follow recoat windows. Check that the door drains freely, the weatherstrip and belt molding fit correctly, and the inner panel is not contaminated. Document the materials, thickness checks, and seam sealer and cavity wax application.
3. What should the shop do if the dent cannot be repaired within the OEM filler limit?
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If the dent cannot be repaired within the 3 mm filler limit, the shop should not simply apply more filler or release the vehicle with a compromised repair. Options include further metal straightening using proper panel repair techniques, replacing the door skin if the OEM permits skin replacement and the necessary tools are available, or replacing the door shell or assembly. The chosen path should follow OEM procedures and preserve corrosion protection. The customer should be informed of the change in repair method and cost before work continues. The final repair file should include the decision rationale, filler thickness measurements, and photos of the completed corrosion protection.