For some, the challenge of identifying the perfect pre-owned semi-truck to buy has been compared to choosing which of your children is your favorite: An impossible task. But it doesn’t need to be as dramatic as that.
More often than not, choosing the right trucks for your large fleet involves the same common sense rules:
- Find out why it’s for sale
- Check the wheels, tires, and lubricants
- Check for corrosion
- Check brakes and lights
Of course, there are major differences in truck type and function, which is where it gets more complicated: Flatbed or tanker? Machinery or logs? Milk or gasoline? Hot or cold? Fleet managers and owner-operators know their specific industrial requirements. But truckers and fleet managers should also be well-steeped in the details of those “common sense” rules.
Tires, Wheels and Lubricants
While looking for things like lug nut damage on the wheels, watch for signs of alignment problems with one-sided tire wear. It is defined by TireReview.com as “…excessive wear across the entire tread surface where the fastest wear is on the outside or inside shoulder rib and each of the adjacent ribs also are worn, but to a lesser extent. Excessive toe is the major cause for this tire condition.”
Also look for rapid shoulder wear on one side of the tire, which TR says, “is the other condition related to trailer misalignment. Excessive camber and a misaligned or bent axle will lead to this rapid shoulder wear condition.”
“Tires have a history of neglect and underinflation,” the TR article adds, concluding that, “Tires underinflated against fleet specification will magnify these irregular wear alignment-related conditions and lead to even earlier removal miles and reduced overall fuel economy.”
With lubricants, check for internal contamination. According to Trailer-Bodybuilders.com, “Internal contamination on an axle tube includes slag containing oil, metal, water, and rust. If the axle is unplugged, the vibratory action can force contamination into the wheel end. Rust forms when water condenses in the tube.”
The Technology and Maintenance Council of the American Trucking Associations has a Corrosion Control Action Committee, and the related Trailer Corrosion Control Task Force. When buying, inquire about their worst offenders, including:
- Electrolytic reaction between dissimilar metals, typically steel and aluminum in trailers.
- Evidence of infrequent washing, allowing road salts to damage floor, undercarriage
- Electrical components that attract corrosion, like upper coupler and kingpin
Brakes and Lights
When it comes to stopping power, it’s smart to test automatic application of the spring brakes. Make sure the supply valve is open (pushed in), and that air pressure is in the normal operating range and the trailer is fully charged. Then close (pull out) the supply valve. Air should be heard exhausting from the spring brakes. If the spring brakes do not apply, they are defective. This is one method; there are others.
To check that lighting systems are working properly on a pre-owned truck, TruckingInfo.com recommends the following:
- Check the condition of the 7-way connector
- Start testing from the front of the trailer beginning with the 7-way socket. Disconnect one piece of the harness at a time and check the circuit.
- Check lamps with a lamp tester
- With the power on, check the pigtail for continuity
- Visually check connections and wire jacketing
- Visually check for bad bulbs (just one can affect the whole system)
Maintenance & Used Commercial Trucks
Along with a basic systems review on a pre-owned semi truck, also examine its service records, verify major parts, and locate a replacement parts source (really important).
Some of the most in-demand pre-owned semi trucks are expected to be those featuring E track and other load securing systems to safely secure cargo; spring suspension units for sensitive loads; and units with air ride suspension to help reduce cargo damage.
In the reefer segment, trailers with heavy-duty duct floors and insulation, tight temp controls, and flexible multi-compartment systems are “hot” right now (pun intended). Flatbed trucks are experiencing strong demand as well, including those with lighter aluminum and steel constructed flatbeds for increased payload capacity.