Trailer Inspections: What Needs to Be Checked?
When it comes to road safety and regulatory compliance, trailer inspection is more than a formality. It is a critical part of ensuring your cargo arrives safely, preventing costly downtime, and protecting drivers and other motorists on the road.
Whether you are an owner-operator or managing a commercial fleet, knowing exactly what needs to be inspected and how often is essential for keeping equipment in top shape and compliant with federal and provincial rules.
Below is a complete breakdown of what a proper trailer inspection should include and why each step matters.
Why Trailer Inspections Are Essential
Your trailer is the backbone of your operation. While truck inspections often get the most attention, it is just as important not to overlook the trailer. Regularly taking time to inspect your trailer helps you:
- Improve road safety by identifying defects early
- Stay compliant with DOT and Transport Canada regulations
- Avoid fines and out-of-service orders at roadside inspections
- Reduce repair costs by catching wear before it escalates
- Extend the lifespan of your equipment
A thorough trailer inspection is not just about checking boxes. It is about preventing breakdowns, accidents, late deliveries, and costly operational interruptions — many of which originate from trailer issues rather than the truck itself.
The Three Types of Trailer Inspections
Pre-trip inspection
This visual and functional inspection is required by law before every trip. The driver must verify that the trailer is safe to operate.
Post-trip inspection
Performed at the end of the driving day, this inspection helps identify issues that occurred during the trip so they can be repaired before the trailer hits the road again.
Periodic maintenance inspection
Performed every 6 to 12 months depending on your jurisdiction, this is a deeper inspection usually completed by certified technicians. These inspections often meet annual DOT or provincial standards.
What Needs to Be Checked in a Trailer Inspection
A proper trailer inspection involves much more than checking lights or looking at the tires. Below is what should be reviewed every time you inspect a trailer.
Braking System
The braking system is one of the most important safety components. During a trailer inspection, verify that:
• Brake lines are free of leaks or corrosion
• Air pressure levels are correct
• Linings and drums do not show excessive wear
• Emergency and parking brakes function properly
Proper brake maintenance prevents failures, improves stopping distance, and helps you pass roadside inspections without issue.
Tires and Wheels
Faulty tires are one of the leading causes of breakdowns and accidents. Inspect for:
• Proper tire inflation
• Adequate tread depth
• No bulges, cuts, or embedded objects
• Rims free of cracks
• Lug nuts tightened correctly
Regular tire checks also improve fuel efficiency and reduce the risk of blowouts.
Lights and Electrical System
Lighting issues are one of the most common reasons for inspection failures. Make sure all lights work properly, including:
• Brake and signal lights
• Side markers and reflectors
• License plate light
• Interior cargo lights
• Wiring free of corrosion or damage
Good lighting keeps you compliant and prevents roadside delays.
Suspension and Frame
A healthy suspension system helps absorb road impact and keeps cargo stable. Inspect:
• Leaf springs for cracks or breaks
• Bushings and bolts for wear
• Shock absorbers for leaks
• Trailer frame for rust, cracks, or bent members
Problems in this area can compromise stability and load distribution.
Coupling Devices and Kingpin
A secure connection between truck and trailer is essential. Check that:
• The fifth wheel locks securely
• The kingpin is not worn or cracked
• Jaws, latch, and handle operate smoothly
• Grease is applied as needed
Coupling failures are extremely dangerous, so this step should never be skipped.
Cargo Securement and Doors
Inside the trailer, make sure that all cargo is properly restrained. Inspect:
• Straps, chains, and load bars for wear
• Anchor points or E-tracks for strength
• Doors and locks for secure closing
• Weather seals to protect cargo
For refrigerated or insulated trailers, check temperature systems and insulation as well.
Fluid Leaks and Undercarriage
Walk around the trailer and inspect underneath for any signs of:
• Hydraulic or oil leaks
• Air leaks
• Rust or cracked welds
• Missing bolts or loose fasteners
Early detection prevents costly structural or mechanical failures.
Documentation and Safety Equipment
A complete trailer inspection also includes checking:
• Up-to-date inspection decals
• Fire extinguisher and warning triangles
• Proper reflective tape
• Valid registration and insurance paperwork
Compliance with DOT and provincial safety standards depends on proper documentation.
Best Practices for a Reliable Trailer Inspection Routine
Even experienced drivers sometimes overlook critical points. Here are the best practices to avoid errors
• Use a standardized checklist every time
• Document all inspections and repairs
• Train drivers regularly
• Work with a professional maintenance provider
Preventive maintenance is always cheaper than unexpected repairs or roadside violations.
Trust TMS TruckMasters With Your Trailer Inspections
Keeping a trailer roadworthy takes expertise, proper tools, and attention to detail. Working with certified technicians ensures that every component meets safety and regulatory standards.
TMS TruckMasters specializes in complete trailer inspection, truck and trailer repair, as well as maintenance services for fleets and owner-operators. Our team ensures your trailers remain safe, compliant, and ready for the road.
Contact TMS TruckMasters today to schedule your next trailer inspection or set up a preventive maintenance plan.