DIY car repairs have become increasingly common across the UK, driven by online tutorials and rising repair costs. While some basic maintenance tasks are perfectly safe, poorly executed DIY repairs can create serious safety risks. MOT tests play a vital role in identifying dangerous DIY work and ensuring vehicles on UK roads meet minimum safety standards.
Many drivers attempt DIY repairs with good intentions, but without professional tools or training, mistakes are easy to make. Improperly fitted brake components, insecure exhaust systems, or incorrectly repaired suspension parts can all compromise vehicle safety.
Common DIY issues include poorly secured parts, non-approved replacement components, and temporary fixes that were never designed for long-term use. These faults may not be obvious during everyday driving but can fail under stress, putting drivers and other road users at risk.
The MOT test is designed to assess whether a vehicle meets basic road safety and environmental standards. Testers are trained to spot signs of unsafe repairs, particularly in safety-critical areas.
Key areas where DIY repairs are often identified include braking systems, steering and suspension, tyres, lighting, and exhausts. Loose fixings, excessive play, leaks, or signs of welding or patching in structural areas will raise concerns. If a repair affects the vehicle’s integrity or performance, it may result in an advisory, major defect, or outright failure.
Some of the most frequent DIY-related MOT failures involve brake components fitted incorrectly, such as pads installed the wrong way round or damaged brake lines. Suspension repairs using incorrect bolts or poorly welded parts are also common.
Electrical faults caused by amateur wiring can lead to lighting failures, warning lights remaining illuminated, or battery drain. Even cosmetic DIY work can cause problems if sharp edges or insecure panels pose a safety hazard.
By identifying unsafe repairs, MOT tests help prevent serious accidents caused by mechanical failure. A vehicle may feel fine during normal use, but the MOT inspection applies checks that simulate real-world stress and wear.
Reviewing previous MOT results can also highlight patterns of repeat issues. Using a vehicle history checker such as the MOT lookup tool on CheckMot.com allows drivers to spot recurring advisories and address problems before they escalate.
Not all DIY work is unsafe. Simple tasks such as replacing bulbs, wiper blades, or air filters are generally low risk when done correctly. The key is knowing your limits. Safety-critical repairs should always be carried out or inspected by a qualified mechanic to ensure compliance with MOT standards.
Yes. If a DIY repair affects safety, structure, or emissions, it can result in an MOT advisory or failure.
They assess the safety and condition of components, not who carried out the repair, but poor workmanship is often obvious.
Temporary or makeshift repairs are likely to fail if they compromise safety or durability.
An MOT confirms minimum safety standards at the time of testing, but ongoing maintenance is still essential.
You can review a vehicle’s MOT history online to identify past warnings and repeated faults.