Top MOT Failure Reasons And How To Avoid Them

For many UK drivers, especially those with older vehicles, the approach of an MOT test can be a source of dread. Conducted by authorised garages, these annual vehicle tests evaluate everything from brakes and lights to emissions and are crucial to ensure that cars travelling on UK roads meet safety and environmental standards. However, it’s often the simple, preventable issues that lead to failures, so in our latest article, Motorscan delves into the top MOT failure reasons and provides practical tips to help you avoid these common pitfalls and keep your vehicle passing the test for many years!

The purpose of an MOT Test

An MOT test is a mandatory annual inspection required for vehicles over three years in the UK, designed to ensure they meet safety and environmental standards. This test checks crucial components such as brakes, lights, emissions and structural integrity. Passing the MOT is essential for maintaining road safety and ensuring your vehicle remains legal. Failing the test means your car cannot be used on public roads, highlighting the importance of regular maintenance and prompt repairs.

Common MOT Failures

Frequent issues leading to MOT failures often involve fundamental problems like blown bulbs, worn front wiper blades and brakes, tyre tread depth below the legal limit, and emissions exceeding permissible levels. These common issues underscore the importance of conducting regular checks and maintenance. Statistically, around one-third of vehicles fail their MOT on the first attempt, often due to simple problems that drivers can rectify themselves. Such fundamental issues underscore the need for drivers to address these common problems before undergoing the test to ensure a higher chance of passing. 

Top MOT Failure Reasons

Understanding the common reasons why vehicles fail their MOT can help you avoid unexpected setbacks and test failures. Motorscan outlines the top reasons vehicles fail their MOT and practical tips to keep your car in top shape and ready for its MOT. Some are basic tasks you should be able to carry out yourself, and others you may need to employ the services of suitably qualified professionals:

Lighting and Signalling

• Common issues: Blown bulbs, faulty indicators, non-functioning number plate lights.
• Prevention tips: Regularly check all lights, clean lenses, and promptly replace faulty bulbs. Ensure all lights, including indicators and hazard lights operate correctly.

Suspension

• Common issues: Worn-out shock absorbers, broken springs, leaking dampers.
• Prevention tips: Listen for unusual noises while driving, monitor vehicle height and stability regularly, and promptly address any signs of suspension wear. Check for oil leaks from shock absorbers which may indicate a problem.

Brakes

• Common issues: Worn brake pads and brake discs, as well as corroded brake lines.
• Prevention tips: Regularly check brake performance, listen for unusual noises like squealing or grinding, and maintain brake components in good condition through regular inspection and servicing. Check brake fluid and top up if necessary, ensuring it’s contamination-free.

Tyres

• Common issues: Low tread depth (below 1.6mm), cuts, bulges or rubber cracking in tyres, including the tyre wall, and incorrect tyre pressure.
• Prevention tips: Use a tread depth gauge to check tyre depth regularly, ensure tyres are correctly inflated according to vehicle manufacturer guidelines, and inspect for damage or uneven wear patterns. Check the spare tyre, too, if applicable.

Visibility

• Common issues: Dirty or damaged windscreens, worn wiper blades, faulty headlight aim.
• Prevention tips: Keep the windscreen clean inside and out, replace worn wiper blades promptly, and ensure wipers effectively clear water and debris for optimal visibility. Windscreen chips or cracks should be within the legal limits, and the aim of the headlight should be checked and adjusted if necessary.

Body and Structure

• Common issues: Rust or corrosion on structural components, insecure body panels.
• Prevention tips: Regularly inspect the vehicle body for signs of rust or corrosion, especially in vulnerable areas like wheel arches and sills. Ensure all body panels are securely fastened and free from excessive rust.

Steering

• Common issues: Excessive play in the steering wheel, power steering fluid leaks.
• Prevention tips: Check steering responsiveness and ensure no fluid leaks in the power steering system. Address any unusual steering feel or noises promptly. Verify the condition of steering linkage components.

Seat Belts and Restraint Systems

• Common issues: Damaged or frayed seat belts, faulty seat belt buckles.
• Prevention tips: Inspect seat belts for wear and tear and ensure all restraint systems, including seat belt buckles and anchorages, are functioning correctly. Test automatic locking retractors and tensioners where applicable.

Exhaust and Emissions

• Common issues: Exhaust leaks and high emission levels (CO, CO2, NOx).
• Prevention tips: Regularly test emissions to ensure compliance with UK regulations, and promptly repair any exhaust leaks or issues to minimise harmful emissions and ensure environmental compliance. Check the exhaust system for signs of corrosion or damage.

How to Prevent Common MOT Failures

Carrying out regular maintenance is the cornerstone of a trouble-free MOT; this includes timely oil changes, brake checks, and ensuring your lights and indicators are in good working order. Similarly, conducting pre-MOT checks can help identify potential issues before the big day, boosting your chances of passing. Take the time to inspect critical elements such as tyre condition and tyre tread depth. Ensure windscreen wipers are working effectively, seat belts are functional, and all bulbs are working. Check for any warning lights on the dashboard. 

Additionally, professional inspections can provide a more thorough review, identifying hidden problems that may go unnoticed. By staying proactive with vehicle upkeep and carrying pre-MOT checks, you can ensure a smoother, stress-free MOT experience and increase the likelihood of an MOT pass.

Common Questions and FAQs answered by Motorscan

1. What are the most common reasons for MOT failures?

Issues such as worn tyres, faulty lights and indicators, braking system problems like worn brake pads or discs, emissions exceeding legal limits, and issues with suspension components make up the common MOT failures.

1. How can I avoid MOT failures?

MOT failures can be avoided by regular vehicle maintenance and checking critical components such as tyres, lights, brakes, and emissions. Address any issues promptly before your test and consider professional inspections for a thorough review.

1. What should I do if my car fails its MOT?

You should address the identified issues promptly and repair the faults that caused the failure. Once the repairs are completed, schedule a retest with an authorised MOT testing station. 

1. Can I take my car elsewhere if the MOT fails?

If your car has failed its MOT test, driving a vehicle on a public road is illegal unless it’s being driven to a pre-arranged test or a garage for repairs.

1. How often should I check my car’s tyres?

You should check your car’s tyres at least once a month for signs of wear, damage such as bulges or cuts and correct inflation. A thorough inspection should also be carried out before any long journeys or an MOT test.

1. Are there any simple checks I can do to prevent MOT failures?

Performing simple checks like checking lights work, reviewing tyre tread depth, ensuring wipers work effectively, and monitoring brake performance can help prevent common MOT failures.