“Salt eats cars” warns a sign at the local car wash.

I would add that certain types of salt are especially damaging to certain parts of cars. Over the past decade, I have seen a dramatic and alarming increase in corroded brake and power steering lines on some models. Brake tubing is crucial to safety, and tedious to repair.  

Researching the problem, I learned that a bad combination of road treatment chemicals and brake line materials had been the culprit. Fortunately there have been advances in technology for both these products, so cars are better protected.    

Caretakers of our roads have not only to treat the pavement with salt , but also repair the vehicles damaged by it, so Jay Nason, Fleet Supervisor for Scarborough Public Works, gets to see all sides of the issue. Nason explained that the salt product has changed over the years. In the 1990s, a combination of rock salt and sand were used. In the early 2000s, salt brine became more common.

Spraying roads with a liquid solution of salt is more economical and effective than spreading solid grains that bounce away. Brine costs less, penetrates snow and ice faster, and coats the asphalt more thoroughly. Unfortunately, the liquid also invades nooks and crannies on vehicles, and corrodes the metal.

While use of salt brine was ramping up, auto manufacturers were phasing out a carcinogenic coating for steel brake lines and other car parts. The replacement coating is not as effective and led to an abundance of rusted brake lines. Alternative materials are available for a price, such as steel tubing with plastic coating, or tubing made of copper nickel alloy and even stainless steel.

I was disappointed to see a 2012 sedan designed with brake lines wrapped in loose plastic conduit, similar to electrical harnesses. I predict that the conduit will trap moisture instead of block it, and then hide the resulting corrosion.

Nason said Scarborough and other towns in Maine have switched to a road treatment that includes a rust inhibitor. The inhibitor slows the reaction time, but it doesn’t prevent corrosion. For local traffic, this is good news, although long-distance travelers will be challenged to plan routes that protect their vehicles.     

To prevent road salt from destroying your vehicle, Nason recommended washing it as soon as possible after every storm. Rinsing the undercarriage with straight water to neutralize the salt is especially important, so spend the extra money on a bottom blast.

There are many undercoating products that can be applied to a vehicle before rust sets in, but none of them are perfect for the long term. If applications are repeated often enough, undercoating works better, but in Nason’s view, thorough cleaning in preparation for the coating is the key factor in preventing corrosion.    

My pet peeve is brake lines, but the entire undercarriage is at risk of salt damage. At least we can take some satisfaction from the preventive maintenance service for this problem. Unlike oil changes, car washes will make our rides look good, too.

Ruth Morrison is an Automotive Technology Instructor and Department Chair at Southern Maine Community College. She holds certification as an ASE Master Technician and Advanced Level Specialist and was a former Ford Senior Master Technician.

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