Rust Busters: Buy A Used Semi That Lasts By Inspecting These 4 Common Corrosion Points

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With the average semi truck logging about 45,000 miles each and every year, rust is a major concern when shopping for a used rig. The good news is that semis are built to withstand the wear, tear, and corrosion that comes along with these vast driving distances, but only if they're properly maintained. When shopping for commercial trucks for sale, make sure its former owner took the steps to protect the vehicle from corrosion by paying close attention to the following rust trouble spots.

Axle Housing

This is a big problem for trucks that have spent much of their lives hauling liquid loads. When liquid loads aren't properly contained, they drip and spill out of the trailer and onto the rear end housing.

If the truck you're looking at has a minimal amount of rear end housing surface rust, you can likely nix the problem by cleaning the area and then coating it with a corrosion-resistant paint. If the rust is extensive enough to appear flaky, though, this isn't the truck for you. Rust flakes from your axle housing can make their way into your bearings and cause bearing failure.

Frame Rails

If the bottom of a truck's frame rails is rusted, it will be readily apparent with a quick peek at the undercarriage. On double frames, though, you've got to be a little more aggressive with your corrosion inspection.

Frame corrosion on double framed semis often starts between the two frames, where's it can't be easily seen. Take a good look between the upper and lower flanges; if you find excessive scaling, continue your search for a used semi truck.

Steering Column And Gear Box

Greasing a semi truck's steering column and gear box not only keeps the parts operating smoothly, but it also helps protect against any damaging salt water the truck may face in coastal territories or on roads that have been prepped for winter storms.

When inspecting a used semi for corrosion, examine the entire length of the steering column from one outer track rod end to the other, including the steering and idler boxes. If you see any rust, or if the area seems dry, then this truck has not been properly greased by its former owner. 

If the area does appear to be greased well, further clarify that it's been properly maintained by asking the semi truck dealer to see the vehicle's maintenance log.

The Wheels

Former truck owners who has neglected their rig until it's time to sell will often do everything they can to hide the corrosion damage on their semi trucks. They may clean up and paint over body rust and lube the steering column up good, but they usually forget one small detail -- rust on the wheels. Because of this, the condition of the wheels can be a telltale sign of how well a semi has been maintained.

Look for signs of rust around the lug nuts. Remove the hubs and have a peek behind them, too. Check for weld marks on the rims; some truck owners may try to fix the beginning stages of corrosion by welding new metal over the existing material. It's never safe to weld a wheel, and if you find weld marks, you can bet the truck's former owner was willing to cut costs in other maintenance areas, too.  

Today's semi trucks are capable of logging over a million miles in their lifespans, but only if they're properly maintained. If you're in the market for a used rig, make sure any vehicle you look at has been treated properly by inspecting the above 4 common semi truck rust trouble spots for corrosion.