Print
The use of dissimilar metals together in one area of the vehicle structure, and the attachment methods used with those materials, can affect damage analysis and repair versus replace decisions. Two models from Mitsubishi that require these considerations are the Lancer Evolution and Outlander.
The Lancer Evolution and Outlander are equipped with an aluminum roof, on models without a sunroof (see Figures 1 and 2). On models with a sunroof, the roof panel is made from steel. On vehicles with an aluminum roof, the roof panel is attached to steel roof rails and roof bows.
According to the 2008-2010 Lancer Evolution and 2007-2010 Outlander Body Repair Manuals, the aluminum roof panel is made from a type of aluminum containing magnesium, copper, and silicon. The manuals state that this type of aluminum has the equivalent strength of cold-rolled steel sheets.
Roof Panel Attachment
The aluminum roof panel is rivet-bonded to the front, side, and rear roof rails, and bonded with adhesive alone to the inner sides of the front and rear roof rails and to the center roof bow. Self-piercing rivets (SPRs) are used for the factory rivet-bonding attachment.
Roof Panel Removal
Following the removal of the SPRs, the roof panel is ready to be separated from the body at the bonded locations. To assist in the removal process, heat can be used in the bonded area of the damaged panel with a flameless heat source up to 204°C (400°F). As the adhesive gets warmer, its strength and bond will weaken. Heating above 204°C (400°F) may weaken high-strength steels and aluminum. The lower center roof bow on the Lancer Evolution, and the inner side roof rails on both the Lancer Evolution and the Outlander are high-strength steel parts.
Installing a Replacement Roof Panel
Figure 2 - (Mitsubishi media photo) This 2008 Mitsubishi Outlander has a rivet-bonded aluminum roof panel.Blind rivets and adhesives are used for the replacement roof panel attachment. The recommended rivet diameter is 4.8 mm.
The adhesive used for the rivet-bonding is different from that used for the attachment areas with just adhesive. The Lancer Evolution and Outlander body repair manuals state to use an epoxyayresin structural adhesive for the rivet-bonding attachment, specifically 3M AAD Part No. 8115 or equivalent. For the adhesive bonding attachment, a urethane body sealer, specifically 3M AAD Part No. 08360 or equivalent is recommended.
The recommended adhesives are applied to the appropriate locations, noted in the repair manual. The adhesive maker's recommendations should be followed for part preparation.
For specific instructions, refer to the vehicle maker's technical information at www.mitsubishitechinfo.com. This is a subscription-based web site. Subscriptions are available for one day, seven days, 30 days, six months, or one year.
Conclusion
Estimators, auto physical damage appraisers, and collision repair technicians must provide complete and accurate diagnosis and repairs to maintain the reliability of a vehicle structure. Damage analysis and repair versus replace decisions have become more challenging because of the increased use of dissimilar materials in vehicle construction, such as the rivet-bonded aluminum roof panel on some Mitsubishi Lancer Evolution and Outlander models.
Photos courtesy of Mitsubishi Motors North America, Inc.
This article first appeared in the March 31, 2010 edition of the I-CAR Advantage Online.
