Semi Truck Pre-Purchase Inspection Checklist
What a mechanic should inspect before you buy — and how the VIN's DOT history tells you where to focus.
Last updated: June 2026 · Data sources: NHTSA vPIC (live) and FMCSA public inspection records (periodic refresh).
Quick answer
A semi truck pre-purchase inspection should cover brakes (adjustment, lining, drums, air leaks, ABS), tires and wheels (tread, cracks, fasteners), steering and suspension, frame, lighting, and fluid leaks. Use the truck's FMCSA DOT roadside history to target the inspection — if brakes were repeatedly cited, prioritize the brake system and request repair proof.
Free FMCSA roadside summary. We accept exact 17-character VINs only and never silently correct a VIN.
Core inspection points
- Brakes: adjustment, lining/drum condition, air leaks, ABS faults
- Tires & wheels: tread depth, sidewalls, cracked rims, torqued fasteners
- Steering: free play, tie rods, drag link, kingpins
- Suspension: springs, U-bolts, shocks, axle alignment
- Frame: cracks, prior welds, corrosion
- Engine/aftertreatment: leaks, fault codes, DEF system
Let the VIN's history target the inspection
A TruckWhere report flags repeated systems and out-of-service events for the exact VIN, so your mechanic knows exactly where to look and what documentation to request.
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Frequently asked questions
- How does DOT history help the inspection?
- It shows which systems were cited historically, so the inspection focuses where risk is highest.
- Can I do this myself?
- Some checks yes, but a qualified commercial-vehicle inspector is strongly recommended before purchase.