For years, U.S. investigators were puzzled why the brakes on thousands of U.S.-made trucks and SUVs were failing without warning. Brake failures were behind at least 107 crashes and there were fears the problem could affect up to two million vehicles On Thursday, after four years of study, the National Highway Traffic & Safety Administration (NHTSA) said it had solved the mystery: Salt. In a “broad” public warning, the agency told millions of Americans to “thoroughly wash the underside of their vehicles.” Investigators found unexpected brake failure could happen to anyone driving a 2008 and earlier vehicle in a cold-weather state. “We need owners to be vigilant about ensuring they, their passengers, and others on the roads are safe,” said Mark Rosekind, the U.S. agency’s head. Canadian drivers should also be paying attention. After all, there are few roads north of the border that do not receive an annual dump of salt. “Brake lines, they’ll just rust away, and it seems to be happening sooner on newer cars,” said Clint McKenzie, a service manager at Active Green + Ross in Barrie, Ont. “Which is pretty scary, given that if your brake line blows, your brakes are essentially gone.” The NHTSA probe, which began in 2011, looked at GM trucks made in 1999-2003 after numerous reports some of the U.S.’s largest passenger vehicles seemed unusually prone to sudden brake failure.
Among the suspects: the Cadillac Escalade, the Chevy Suburban and the GMC Yukon. Investigators sent out surveys, pored over safety records, and inspected 71 randomly selected vehicles — but turned up nothing worthy of a recall. “A safety-related defect has not been identified at this time,” concluded the investigation, which was officially closed Wednesday. Instead, the probe came to the chilling finding sudden brake line ruptures were not limited to a couple of million GM cars. Rather they could be a danger to anyone behind the wheel of an older model truck or SUV in one the U.S.’s “salt states.” “Salt and other chemicals can accumulate on road surfaces, can accumulate on your vehicle’s underbody, and could put you and your passengers in danger,” says a safety video issued Thursday by NHTSA. The precise tipping point identified by the report was only eight years. By that point, cars driven in “harsh conditions” would have built up enough corrosion to produce dangerous structural problems. ‘Salt and other chemicals can accumulate on road surfaces, can accumulate on your vehicle’s underbody, and could put you and your passengers in danger’ Hence, the agency’s call to cold-weather drivers to “regularly wash the undercarriage throughout the winter” and schedule at least two safety inspections a year.
That probably means going to a car wash. It’s a tricky task to attempt with a garden hose, particularly in winter. Mr. McKenzie said regular washes are surprisingly effective at staving off corrosion. For example, hosing down wheels can extend their life by up to three times. Environment Canada estimates up to nine million tonnes of salt are scattered on Canadian roads each winter. Although this obviously prevents an untold number of ice-related car crashes, the salt has been linked to reduced agricultural fertility and damage to the “aquatic environment,” as well as corrosion on cars and damage to highway infrastructure. Last year, Toyota Canada had to recall 82,381 Sienna minivans because road salt was causing the vehicles’ spare tires to break free. The problem was remedied by mechanics installing a “water splash protector.” Most famously, salt-included corrosion is behind the premature degradation of Montreal’s Champlain Bridge, the most travelled span in the country. The bridge, which opened in 1962, has been brought close to collapse by repeating salting, requiring a replacement that will cost between $2 billion and $5 billion.