Preventing Trailer Corrosion: Spec'ing To Cope

Aggressive road-deicing chemicals are a reality, and wise managers cope with it by spec'ing robust products and materials. Remember that you won't get such things by ordering on price alone. Here are some tips to consider and use:

When ordering new trucks, tractors and trailers, specify top-quality electrical products that are sealed against the ravages of moisture and salts, and see that they are installed intelligently.

Insist that wiring for truck bodies be plugged into special chassis connectors. Don't let body upfitters cut into chassis wiring to get power for their lighting.

Use hermetically sealed connectors designed to block entry of moisture. Electrical parts are "potted" in urethane or other materials, and can be immersed in water and still work. In non-sealed connectors, apply dielectric grease to displace moisture and promote conductivity.

Avoid connectors with top-mounted lids through which moisture can drop.

Mount connectors in a protected place on the vehicle, and avoid spots where water can collect. If outside, like under a trailer, connectors should have sealing covers to deflect spray, or boots that can be sealed with adhesive. 

Mount connectors horizontally so moisture drops harmlessly off their bottoms instead running toward seals and joints, as it does on vertically mounted connectors. 

Put loops into outside-hung wiring so moisture has a place to collect and fall off. Never allow exposed wiring anywhere in the vehicle.

Use couplings of the same metals; electrolysis between dissimilar metals results in additional corrosion.

Avoid side-loading of connectors. This drains power and introduces more opportunity for corrosion.

Don't allow use of hygroscopic materials - anything that absorbs moisture - near electrical components. Some plastics are hygroscopic, and some gasket substances used in grommets are, too. 

As part of regular maintenance, inspect wiring and connectors closely, looking for any signs of corrosion. 

When repairing electrical parts, use supplies and techniques that retain the integrity of the sealing materials.

Be aware of any fluids that may come in contact with connectors and other parts. For example, a mechanic can spill windshield washer fluid onto an underhood connector box as he refills the reservoir; can the box shrug off the water? 

Brad Van Riper of Truck-Lite Inc., who offered these tips at an industry meeting not long ago, summed up his advice thusly: "Seal everything and use everything sealed. Use potted circuit boards to minimize corrosion. Use materials in your designs that are as corrosion-resistant as you can afford."