Trailer failed inspection – causes, solutions and what to do next
When a trailer fails a roadworthiness inspection, it is almost always due to safety-related defects. The good news is that most failures are caused by worn or faulty components that can be identified in advance and replaced relatively quickly. Rules on inspection requirements, intervals, and defect categories vary by country – always check the regulations that apply in your region.
What are the most common reasons a trailer fails inspection?
The following defects are among the most frequent causes of inspection failure across Europe:
– Faulty or non-functioning lights
– Uneven or insufficient braking force
– Worn brake shoes
– Stiff or damaged brake cables
– Problems with the overrun brake
– Damaged tyres or incorrect tyre pressure
– Play or wear in the coupling head
How are defects typically categorised?
In most European countries, inspection defects are divided into categories based on severity – typically something along the lines of minor, major, and dangerous. Minor defects may require no immediate action, while major defects usually require a re-inspection within a set period. Dangerous defects typically mean the trailer must be taken off the road immediately. The exact categories and rules vary by country, so always check local regulations.
What should you do after failing an inspection?
Once the defects are identified, have them repaired as quickly as possible and book a re-inspection. In most cases the re-inspection fee is lower than a full inspection, but it still pays to fix everything properly the first time to avoid repeated failures. Make sure all repairs are carried out correctly – a rushed fix that fails again will cost more in the long run.
Brakes not working correctly
Brake-related failures are among the most common. The problem is often incorrect adjustment or worn components. Check the brake shoes for wear and inspect the brake cables for stiffness, fraying, or incorrect tension. If the brakes are simply out of adjustment, see the guide on how to adjust trailer brakes.
Lighting not working
Defective rear lights or poor electrical connections are a frequent cause of failure. Replacing a faulty light unit is usually straightforward. For an overview of trailer lighting requirements and options, see the trailer lighting guide. Always ensure your trailer lighting is fully functional before attending an inspection.
Problems with the overrun brake
If the overrun brake jerks, fails to engage smoothly, or does not release properly, the cause may be a worn damper, stiff cables, or incorrect adjustment. See the guide on overrun brake not working for a breakdown of common causes and solutions.
Tyre condition and pressure
Damaged tyres, uneven wear, or incorrect tyre pressure are all grounds for failure. Check the tyre sidewalls for cracks or bulges, and ensure the pressure matches the manufacturer’s specification. For guidance see the page on trailer tyre pressure.
How to avoid failing inspection in the first place
A thorough check before the inspection date is the best way to avoid a failure. Go through the brakes, lighting, tyres, coupling, and overrun system. Replace any worn parts in good time. Brake drums and wheel bearings are worth inspecting too, as these are often overlooked until a problem becomes serious.
Summary
A failed trailer inspection is frustrating but usually straightforward to resolve. The most common causes are worn brake components, faulty lighting, and tyre issues – all of which can be identified and fixed with basic maintenance. Inspection rules and defect categories vary by country, so always check what applies in your region.