| May 31, 2016

For unibody repairs, GM bolt-on structure parts save time

Repair or replace. That’s the basic choice when it comes to restoring damaged vehicles.

But there’s more to the story. Today, thanks to advances in parts and repair technology pioneered by companies like GM, replacement doesn’t have to be wholesale. Replacement can also be partial, leading to big savings with no sacrifice in quality.

Secondary, unibody damage is a case in point. In front-end collisions significant enough to cause air-bag deployment, upper and lower frame rail sections directly behind the bumpers are often damaged. Increasingly, these areas are made from aluminum or high-strength steels that cannot be repaired, as they are designed to crush or change properties (work harden) with the force of impact. They are essential elements of sacrificial “crash boxes” that are tuned to absorb energy and set the tone for air-bag deployment.

Their construction and location, though, make straightening or other repair very difficult when they’re crushed. The typical solution has always been front rail assembly replacement for cars and entire frame assembly replacement for trucks. But that can be costly, in both labor and parts. So costly, in fact, that damage in older vehicles can lead to a total loss.fasteners

“Bolt-on rail end parts take the guesswork and complexity out of where to perform partial rail replacement,” says Bob Hiser, Service Engineer with GM Customer Care & Aftersales. And, Hiser adds, “bolt-on partial rail replacement is attractive because it gets the job done quickly and cost-effectively without cutting corners”. In many cases, frame stub or rail end “crash box” repairs can be performed with powertrain or surrounding body and interior components in place. That saves time and further intrusion into a damaged vehicle.

GM is increasingly turning to fasteners rather than welding key structural areas. Some newer models such as the Chevrolet Cruze, Chevrolet Impala, Buick Verano, and Cadillac SRX, have bolt-on rail ends. Bolt-on rail ends are a method for joining dissimilar materials in engineering, and a strategy employed to aid manufacturing stations during vehicle production.fasteners 2

However, the most important benefit may accrue to the collision repair industry. Ever more collision damage can be addressed by unbolting damaged portions and replacing with new bolt-on
parts. With fasteners securing rail ends to the rest of the rail assembly, the biggest issue is removing surrounding components to achieve success.

For many repairs on the new Camaro, the technician will find that front structure measurements reveal no secondary damage to frame rails and structure parts beyond the bolt-on lower rail extensions and the bolt-on tie bar assembly.

With replacement rail parts, repairers can breathe easier. Whether you’re measuring, cutting and welding a new part or simply removing and reinstalling fasteners, GM offers replacement
rail parts that fit onto existing frame assemblies and perform as original equipment. That means repairers don’t have to devise their own partial replacement strategies or be concerned with repair
performance. In the end, you can be assured that partial or full part replacement using Genuine GM Parts installed using GM approved procedures delivers a complete solution.

GM offers Service Information online on a subscription basis and offers select body repair information free of charge at www.GenuineGMParts.com.

front tie bar2016 camaro

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Category: GM Parts News, OE Parts Update, The Technical Side