NHTSA Recommends Washing Under Older Trucks, SUVs

By Mark Stevenson

Sometimes the fix for complex problems is quite simple. In the case of an investigation performed by the National Highway Traffic Safety Administration on brake failures of late-model 1990s and early 2000s full-size pickup trucks and SUVs, one easy-to-understand solution was recommended: Wash the undercarriage of your vehicle.

Wear and tear is a normal part of the life cycle of your car or truck — even more so in northern climates — and taking the time to wash unseen areas will pay dividends in the end. NHTSA report detailed how the lack of such attention could lead to brake failures due to pipe corrosion. Road salt and other chemicals used to treat cold surfaces can stick to parts of a vehicle and corrode them over time.

NHTSA provides a three-point plan for maintaining your braking system to avoid unexpected losses in brake fluid pressure due to leaks.

• 1. Remove road salt that leads to corrosion. Thoroughly clean your vehicle, including the undercarriage, at the end of the winter. Regularly wash the undercarriage throughout the winter.
• 2. Monitor your brake system, including brake pipes and other undercarriage components, for corrosion or signs of brake failure. If you own an older vehicle in a cold-weather state, have a qualified mechanic or inspection station inspect the vehicle at least twice a year. If there are any signs of corrosion, inspect the brakes more frequently, at least every time you bring your vehicle in for service. Keep an eye on brake fluid level. Watch for changes in how your brake pedal feels and for signs of fluid leakage beneath the vehicle. All of these could indicate a leak in your brake pipes.
• 3. If you find severe corrosion that causes scaling or flaking of brake components, replace the entire brake pipe assembly. Do not replace just a portion of the assembly. Failure in one portion of the brake pipes generally means other sections of pipe are at risk of failure. Check with your manufacturer to see if it has prefabricated brake pipe kits to make replacement easier and potentially less expensive.

Additionally, if you live in a region where temperatures are constantly colder than 20 degrees, washing the undercarriage may actually do more harm than good. When salt is in a completely dry environment, it won’t react with metals. Instead, wait for the temperature to rise before washing.

And if you think garaged vehicles are in the clear, think again. If you drive your vehicle during winter months and store it in a garage warmer than 20 degrees, you’re much more likely to see corrosion. Each time your vehicle is parked inside, road salt stuck to the vehicle combines with water and goes to work corroding components all night long.