In case you missed it, the automotive sector went back to the future last week, when the world’s largest automakers announced plans to share more parts and assemblies in an effort to hold down cost and improve quality.

On paper, the move could provide much-needed cost and product stability. However, the auto sector has a dubious track record when it comes to collaborative purchasing and supplier management initiatives. (Consider the now-defunct Covisint. Or ANX the auto industry’s decades old elecronic connectivity initiative that has experienced several false starts and multiple “owners.”)

Spurred by shrinking auto sales and a spate of supplier bankruptcies, purchasing chiefs from GM, Ford, Chrysler, Toyota, and Honda agreed to collaboratively develop and purchase common components and assemblies. Their logic? Building components for use by multiple automakers ensure high volume production runs for suppliers. This not only increases supplier profits and operational efficiency, but it also boosts overall product quality. The move could also infuse some innovation and styling into otherwise mundane products, such as seat frames.

The plan would certainly benefit ailing U.S. automakers. As previously reported here, the Big Three are far less profitable per vehicle than their Japanese counterparts. And the Detroit trio has made commitments to reduce the number of parts and suppliers used in their vehicles. Sharing parts and assemblies would accelerate these efforts. (Although the move will do little to reduce the Big Three’s biggest costs: salaries, pensions, and benefits.)

Purchasing chiefs pointed to several examples where their companies are already collaborating on parts, such as Toyota and GM sharing a common seat frame in certain Chevrolet vehicles; Ford and GM’s co-development of a six-speed automation transmission; and GM and Chrysler’s co-development a hybrid gasoline-electric powertrain. (Although the latter was in a desparate effort to counter the Japanese’s lead in hybrid engines.)

Yet, follow-up interviews suggest that any further collaboration around parts development and purchases will be opportunistic. Ford SVP of Global Purchasing told Bloomberg News: “What you will see going forward is that two, three, or four of us [will share parts], when it makes sense.” Automotive consultants at IRN summed it up best in a Detroit Free Press article, “[Sharing parts] sounds great in theory. It’s much more difficult to execute.”

Indeed, as reported here Toyota and Honda won the first round of the green vehicle war by developing and locking up supply for hybrid powertrains. (In fact, Ford execs publicly complained that this supply approach gave the Japanese an unfair competitive advantage.) Rest assured, no automaker will be willing to give up that kind of edge just to shave a fraction of a percent off an O-ring.

And the arugment that collaborative parts development and buying is good for suppliers is not entirely accurate. Parts sharing means consolidating spend with fewer suppliers. So, if automakers keep their vows to share more parts, expect more suppliers to file for bankruptcy, at least in the near term. And, if the parts sharing practice were to take off, don’t be surprised if the regulators weigh in on the issue. 

Upshot: The latest news is much ado about nothing. (Must have been a slow news week in Detroit.)

The automotive sector may be in desperate times. Yet the desperate measure of collaborative buying will only be used sparingly. The reason is simple: innovation and supply chain are two of the automotive sector’s three pillars of competition. (The third would be manufacturing performance.) While sharing parts may hold down costs, no automaker will engage in such collaborative deals if they threaten a competitive advantage in terms of defensible innovation or supply chain efficiency.