Mark Szlachta, advanced serviceability of design engineer for GM, speaks at the recent SEMA Show on the different types of materials used in the new CT6. At the SEMA Show, each structural equipment company (Celette shown) approved by Cadillac for repairs of its CT6 had a “body-in-white” displayed on its frame bench and fixtures that fit that vehicle. The Cadillac CT6 combines aluminum sheet, extrusions, and castings with mostly high-strength steel, using structural adhesive to bond it together and prevent galvanic corrosion from dissimilar metals.The Wieländer & Schill Xpress 800 structural riveting tool is the only riveting tool approved by Cadillac for repairing its CT6.During repairs, flow form rivets will replace the self-piercing rivets used in CT6 assembly.

General Motors introduces Aluminum Repair Network for its Cadillac CT6

Required for all structural repairs, program will carry annual $4,500 price tag

Las Vegas—In a first for General Motors, it has introduced an authorized collision repair network for its new aluminum-intensive full-size touring sedan. Slated to begin production in January and shipping to dealers in March, the 2016 Cadillac CT6 is made of almost 70 percent aluminum, with the balance being mostly high-strength steel.

All shops will be able to perform mechanical and cosmetic repairs on the CT6, including replacing bolt-on body parts, said Mark Szlachta, advanced serviceability of design engineer for GM, who spoke on the program at the recent SEMA Show in a free I-CAR seminar. But structural repairs of the CT6 will require specific training, equipment, and membership in the Cadillac Aluminum Repair Network, at a cost of $4,500 per year.

The repair process is not difficult compared to other late-model vehicles, Szlachta said, although it is different and requires specialized training and equipment.

“Because of all of the issues, it was a necessity to initiate an aluminum repair network very similar to what other OEs had,” he said. “We’re not recreating the wheel.”

Structural parts and repair data sheets (frame measurements) from the estimating companies will be available only to shops within the network, he said, adding that parts will be available from any GM dealer, and a shop does not have to be sponsored by a dealer. Repair information for the CT6 will be available free of charge at to help repair facilities determine the difference between structural and non-structural repairs.

The vehicle’s outer surfaces are all aluminum, part of its almost 70-percent makeup of cast, extruded, and sheet aluminum, Szlachta said.

“To repair this car, we’re going to put it up on fixtures, and we’re going to peel it back like an onion,” he said. “We’re going to keep taking off damaged parts until we get to the good ones, and then we’ll start putting this car back together.”

The vehicle is assembled with about 600 linear feet of structural adhesive, not to be confused with common lower strength epoxy panel bonding adhesives.

“The adhesive gives us structural integrity, it gives us torsional stiffness, and it’s also an insulator so we don’t have galvanic corrosion,” he said.

Multicolor, easy-to-read specific repair instructions will be available online and will not be packaged with the parts, Szlachta said, pointing out that GM can instantly revise them online. Some of the methods used to repair the CT6 will differ from those used to assemble it, he said.

The car is assembled with self-piercing rivets (SPRs) and aluminum resistance spot welds at the assembly plant, Szlachta said. The new car requires a specific rivet tool to remove the SPRs, although SPRs will not be installed in any repairs, he said. Because SPRs cannot go back in the hole from which an SPR was removed, a flow form rivet will be installed in its place.

MIG-welding is not suitable for repairs because of the structural adhesive used, he said. In place of the aluminum resistance spot welds, which require more powerful welders than are readily available to the aftermarket, flow drill screws are used in the repair, he said, which are installed much like a self-tapping screw and are easy to use.

“The high speed actually starts melting the aluminum as they start going through all of the aluminum stack-ups,” Szlachta said. “It seals itself; it almost welds itself to the vehicle. These are great for service because we can remove them; we can reuse them. And in the event that we strip one, we have a service screw.”

In the event that the hole is too damaged to use the oversize service screw, a blind rivet will be used, he said.

A required piece of equipment for the program is the Wieländer & Schill Xpress 800 structural riveting tool (also used in the Mercedes-Benz and Tesla certified repair programs) with the CT6 accessory kit, which carries a suggested retail price of more than $10,000. It’s the only riveting tool approved for the program, Szlachta said.

“We tested this one for over nine months,” he said. “We cut cars apart with this Wieländer & Schill tool and put them back together. We then sent those vehicles out for testing to make sure the vehicle would meet the same crashworthiness and safety requirements as the original vehicle. We didn’t want to have to hone in on one riveting tool, but the car is what the car is. One of the only tools that can fill the void left by a vacated SPR is the flow form Wieländer & Schill tool.”

Aside from the riveting tool, most equipment must meet specifications instead of being a specific brand and model, including a dedicated pulse-MIG welder for aluminum; an aluminum-isolation bay/curtain; a wet-mix technology aluminum particulate extraction system; an aluminum dent repair station; and a structural repair bench. As of this writing, Car-O-Liner, Celette, Chief, and Spanesi have fixture sets for the CT6.

Szlachta said that GM has selected Axalta Coating Systems to administer the program, and VeriFacts will audit the shops, looking for requirements such as being either an I-CAR Gold facility or a VeriFacts VQ facility. Shops must already be in an OEM-certification program from Audi, Jaguar/Land Rover, Mercedes, or Tesla, or have technicians with training certificates in WCA3 Welding Training & Certification, ALI01 Aluminum-intensive Vehicle Repairs, and APR01 Aluminum Exterior Panel Repair and Replacement I-CAR courses. Technicians must also take GM Web-based training specific to the CT6.

Training will not be limited to repair shops, Szlachta said, and will include educating the customer and insurers about the vehicle and its repair requirements. Cadillac Customer Care and OnStar will help vehicle owners find the nearest Cadillac Aluminum Repair Network facility, Szlachta said, and Cadillac will also pick up the tab to tow the vehicle to the nearest authorized service center and return it to the nearest dealer.

For more information on the network, go to

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