Since January 2011, the National Highway Traffic Safety Administration has been investigating a possible problem with corroding brake lines in General Motors' GMT800-platform models, like the Chevrolet Silverado and Suburban and GMC Sierra, in states with salt on their roads in the winter. However, as opposed to launching a full recall of millions of vehicles, the government is issuing a common-sense safety advisory to all drivers in snowy states to keep their vehicle's undercarriage clean. It even has a video explaining things.

"Older-model vehicles, often driven in harsh conditions, are subject to corrosion over long periods of time, and we need owners to be vigilant about ensuring they, their passengers, and others on the roads are safe," said NHTSA Administrator Mark Rosekind in the announcement of the end of the investigation. The agency was clear in its report that "brake line corrosion seen in the GM vehicles was not unique," and the government "has not identified a defect that would initiate a recall order."

Instead NHTSA is advising drivers, especially those of vehicles from before 2007, to wash their vehicle's undercarriage in the winter and spring to remove salt or other de-icing chemicals. It also recommends regular checks by a mechanic to make sure everything is in proper order.

According to the investigation documents, for just the GMT800 platform models, NHTSA found 3,645 complaints of brake line corrosion, which included allegations of 107 crashes and 40 injuries. The issue was found to be more common in vehicles over 10 years old. GM has released a statement (embedded below) that the company "supports the consumer advisory from NHTSA urging regular maintenance and care of brake lines on older vehicles."
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NHTSA Closes Investigation into Brake-Line Failures

NHTSA 13-15
Thursday, April 9, 2015

Agency issues safety advisory on preventing undercarriage corrosion

WASHINGTON – The Department of Transportation's National Highway Traffic Safety Administration (NHTSA) today issued a Safety Advisory and consumer video encouraging owners of model year 2007 and older trucks, SUVs and passenger cars to inspect brake lines and thoroughly wash the underside of their vehicles to remove corrosive salt after the long winter in order to prevent brake-line failures that increase the risk of a crash.

The advisory was issued in conjunction with the agency's closing of an investigation into brake-line failures in General Motors trucks and SUVs built in model years 1999 to 2003. The agency spent more than four years investigating corrosion-related brake failures in the vehicles and similar trucks and SUVs made by other manufacturers, but has not identified a defect that would initiate a recall order.

NHTSA also issued a closing report that details the investigation's analysis of state safety inspection data and a survey of about 2,000 vehicle owners. The data indicate that the brake line corrosion seen in the GM vehicles was not unique – similar vehicles using comparable brake-lines experienced similar corrosion issues, especially in states using salt to de-ice roads in winter. NHTSA issued a broad safety advisory urging owners of older SUVs and pickups to take steps to prevent brake failure resulting from corrosion.

"While NHTSA can't order a recall in this case, there is a safety issue that vehicle owners should address," NHTSA Administrator Mark Rosekind said. "Older-model vehicles, often driven in harsh conditions, are subject to corrosion over long periods of time, and we need owners to be vigilant about ensuring they, their passengers, and others on the roads are safe."

NHTSA's safety advisory urges owners of trucks, SUVs and passenger cars that are more than seven years old to:

Maintain their vehicle and prevent corrosion by washing the undercarriage regularly throughout the winter and giving it a thorough washing in the spring to remove road salt and other de-icing chemicals that can lead to corrosion.

Monitor the brake system for signs of corrosion by having regular professional inspections and watching for signs of problems, including loss of brake fluid, unusual leaks and a soft or spongy feel in the brake pedal.

Address severe corrosion, marked by flaking or scaling of the metal brake pipes, by having the full assembly replaced.

"If you own an older vehicle and live in a cold-weather state where salt and de-icing chemicals are common in winter, we strongly urge you to take these steps," Rosekind said.

NHTSA's investigation stemmed from a vehicle owner's petition in 2010, and covered about 6 million model year 1999-2003 GM Sierra, Silverado, Avalanche, Escalade, Suburban, Tahoe and Yukon vehicles.

NHTSA examined consumer complaints for brake line failures for all types of light vehicles and analyzed safety inspection data collected in Pennsylvania from 2008 through mid-2014. The agency's Vehicle Research and Test Center in Ohio conducted a survey that gathered data from approximately 2,000 owners of GM and peer vehicles from the period. Investigators also examined 71 randomly selected vehicles in Massachusetts, New York, Maryland and Ohio.

While NHTSA received substantially more vehicle owner complaints about all types of GM vehicles than similar vehicles from other manufacturers, the higher rate of complaints appeared to be at least in part related to public attention given to the investigation. The Pennsylvania inspection data, VRTC survey and random NHTSA vehicle inspections all showed that both passenger car and light truck peer vehicles are subject to similar corrosion-related failure rates. The coated steel brake pipes in GM's vehicles under investigation were similar to materials used by other manufacturers at the time. Beginning in the late 1990s, manufacturers transitioned to plastic-coated pipes that are in use today.

INVESTIGATION Subject : Brake line corrosion failure
Date Investigation Opened: JAN 05, 2011
Date Investigation Closed: APR 08, 2015
NHTSA Action Number: EA11001
All Products Associated with this Investigation

Vehicle Make Mode lModel Year(s)

CHEVROLET 1500 2003


Manufacturer: General Motors LLC

SUMMARY:On January 11, 2011, ODI opened EA11-001 to investigate allegations of premature brake line corrosion failure in model year (MY) 1999 through 2003 General Motors (GM) full-size pickup trucks and sport utility vehicles sold or registered in the following region of the United States that NHTSA has viewed as salt states for investigations of corrosion related issues: Connecticut, Delaware, District of Columbia, Illinois, Indiana, Iowa, Maine, Maryland, Massachusetts, Michigan, Minnesota, Missouri, New Hampshire, New Jersey, New York, Ohio, Pennsylvania, Rhode Island, Vermont, West Virginia and Wisconsin. The subject vehicles represent the first five MY's of GM's GMT800 platform production, of which approximately 2,038,504 vehicles were sold in salt states (the subject vehicles). The GMT800 platform includes the following vehicles: 1999-2007 Chevrolet Silverado and GMC Sierra 1500, 2500 and 3500 series pick-up trucks; 2000-2006 Chevrolet Suburban, Chevrolet Tahoe and GMC Yukon sport utility vehicles; and 2002-2006 Cadillac Escalade and Chevrolet Avalanche sport-utility vehicles. General Motors produced a total of approximately 10,427,062 GMT800 vehicles for sales in the United States, including almost 5 million that were sold in salt states. Although there are over 60 different brake pipe routing configuration used in GMT800 vehicles, with the exception of the rear crossover pipes in MY 200x-2007 vehicles that changed from rear disc to drum brakes, all of the vehicles use brake pipes from the same supplier with a common double-wall, brazed steel pipe design with a combination of hot dip Zinc-Aluminum corrosion protection coating and Aluminum paint outer layer known in the industry as AlGal (ASTM-B750).

ODI analysis of field data regarding GMT800 vehicles identified a total of 3,645 complaints of brake pipe corrosion failures, including 107 alleging crashes, and 40 injuries. Though only 20% of total GMT800 production, due to age and region the subject vehicles account for a disproportionate share of the failure experience; with 2,702 of the complaints (75%), 88 of the crashes (82%) and 20 of the injuries (50%) reported in those vehicles. Analysis of the complaints showed strong correlations to vehicle age and region. For vehicles with less than 8 years of service, the complaint rates were minimal for all regions. In the salt states the failure rates begin to climb as the vehicles advance in age, particularly in the Northeast corner of the United States. The complaint rates in the salt states go from less than 0.1 incident per thousand vehicles (IPTV) at 7 years in service to over 1.0 IPTV after the 12th year of service for the subject pickup trucks and utility vehicles. Most of the failures reported to ODI occurred in vehicles with more than 10 years in service. ODI?s investigation did not identify any specific defect conditions that were causing or contributing to the brake pipe failures. Nor did the analysis isolate the problem to any subject vehicle sub-populations when analyzed by vehicle type or production range. The investigation found that vehicles experiencing brake pipe corrosion failures were likely to have general patterns of excessive corrosion on the majority of the brake pipe assembly and appear to be occurring due to expected wear out for the brake pipe coating material used in the subject vehicles and the environmental conditions in severe corrosion states.

A safety-related defect has not been identified at this time. Accordingly, this investigation is closed. The closing of this investigation does not constitute a finding by NHTSA that a safety-related defect does not exist. The agency will monitor this issue and reserves the right to take further action if warranted by the circumstances. For additional information, see the closing report in the investigation document file.

Statement from GM:

General Motors supports the consumer advisory from NHTSA urging regular maintenance and care of brake lines on older vehicles. GM has proactively suggested to consumers that they perform regular undercarriage cleaning and post-winter brake line inspections to check for wear. Through AC Delco, GM offers specially designed brake line replacement kits for dozens of full-size truck configurations.

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