If the market takes off, the use of copper-nickel tubing for hydraulic brake lines in autos could be a nice piece of business for certain tubing manufacturers and redrawers, according to Bob Weed, vice president of original equipment manufacturer (OEM) markets for the New York-based Copper Development Association (CDA).
The use of alloy C70600 copper-nickel—comprised of about 90-percent copper, 10-percent nickel and a small amount of iron—for this application gained a lot of attention in the early 1970s when Sweden's Volvo Car Corp. made its initial move in this direction, although it stopped using the product in 2002, Weed said.
Several other European automakers are using copper-nickel brake lines (and in some cases power steering lines), especially for high-end vehicles, among them Rolls-Royce Group Plc, Aston Martin Milano Srl, Porsche Holding GmbH, Audi AG and Saab AB, he said. But none of the traditional U.S. "Big Three" automakers or any of the foreign-owned "New Domestics" have followed suit, at least not for the entire length of the brake line.
However, both Ford Motor Co., Dearborn, Mich., and General Motors Co., Detroit, do use copper-nickel tubing in some portions of the brake lines of some vehicles—largely pickup trucks and sport utility vehicles—as light trucks tend to require more-durable brake lines since they are more likely to be used in more severe operating environments, much as Europe's BMW AG and Mercedes-Benz have done.
These automakers on average use copper-nickel tubing for five to six feet per vehicle out of the entire 30- to 50-foot metallic lines for brakes and power steering. Weed said it is used in certain critical areas close to the wheels and those portions of the line more likely to be exposed to gravel impingement and to road salt—conditions that would be more likely to nick the coating on steel tubes.
At last count, about 15 or 16 vehicle models were using at least some copper-nickel brake lines. "It is a growing market, although it is growing very slowly," Weed said, noting that the aftermarket is growing faster than original equipment as the aftermarket has the ability to sell copper-nickel brake lines based on performance and not just cost. Weed acknowledged that with copper-nickel tubing about twice as expensive as conventional steel tubing with an aluminum/polymer epoxy coating, there has been a lot of resistance from cost-conscious automakers.
"Reductions in warranty costs, however, could partially offset this," he said, noting that there are potential safety issues involved, including brake failure if lines become corroded. "This is immeasurable as it involves human safety and life. Brake safety is very much at the forefront of automotive engineering concerns."