Trailers are the most under-inspected purchase in transport. Buyers who would strip a tractor to the frame will hand over money for a trailer after a walk-around — and then discover the cracked crossmembers, soft floor and out-of-date tank certificate the walk-around missed. A trailer has no engine to distract you: it IS the frame, axles and floor. Inspect it that way.
Every trailer: the universal checks
- Frame rails and crossmembers. Get underneath. Look for cracks at weld points, fresh paint over repairs, fishplating and rust scale that flakes to your screwdriver. Crossmember replacement is routine; a cracked main rail is a structural rebuild.
- Kingpin and upper coupler. Measure kingpin wear (gauges are cheap; slop is expensive) and inspect the coupler plate for cracks and delamination.
- Axles, suspension, bearings. Check spring hangers, airbags and torque arms; jack each axle and feel for bearing play. Uneven tyre wear across an axle is the suspension confessing.
- Landing gear. Wind it through full travel both sides — bent or seized legs are a common hidden cost.