How to inspect a semi-trailer before buying: a checklist

A semi-trailer seems simpler than a tractor unit — yet people make just as many mistakes buying one. A rusted frame or worn-out axles will eat up every bit of savings from that "great" price. Here is the short checklist our managers use during inspections.

The key assemblies

• Frame: cracks and welding marks near the kingpin and around the axles are a reason to negotiate hard — or walk away.
• Axles: bearing play, the condition of the brake discs/drums; the axle brand (BPW, SAF) affects the cost of spare parts.
• Brakes: even wear on the pads, the condition of the spring brake actuators, a working EBS.
• Air suspension: airbags with no cracks; the trailer holds its ride height without the compressor running.
• Floor: for curtainsiders, the condition of the plywood under load; for tippers, the thickness of the body metal.
• Curtain and roof: tarps with no patches along the seams, a sliding roof that works properly.
• Documents: the VIN on the frame matching the one in the papers, the year of the axles.

How long the inspection takes

A full hands-on check takes an hour to an hour and a half. At our yard, every unit goes through it before it is ever listed — on the listing you see the honest condition, and during the inspection you can walk through this same checklist together with the manager.