MOT Failures: Common Reasons & How to Avoid Them

The annual MOT test is a crucial part of vehicle ownership in the UK. It ensures your car meets minimum safety and environmental standards. However, many vehicle owners find themselves facing an MOT rejection, which can be a frustrating and costly experience. Understanding the common reasons for failure is the first step towards ensuring your vehicle passes with flying colours. This comprehensive guide will delve into the most frequent MOT failure points and provide practical advice on how to keep your car roadworthy.

Common MOT Failure Categories

MOT tests are divided into several categories, and failures can occur in any of them. The Driver and Vehicle Standards Agency (DVSA) outlines specific criteria for each area. Let's explore the most prevalent reasons vehicles fail their MOTs:

1. Lighting Equipment

Faulty or incorrectly aimed lights are a very common reason for MOT failure. This includes:

• Headlights: Not working, incorrect colour (e.g., blue or green), not aligned correctly (too high or too low), or a cracked casing. The beam pattern must also be correct.
• Brake Lights: Not illuminating when the brake pedal is pressed, or being permanently on.
• Tail Lights: Not working, or being the wrong colour.
• Indicators: Not flashing, flashing too quickly or too slowly, or being the wrong colour (must be amber).
• Number Plate Lights: Not illuminating the rear number plate correctly.

Tip: Regularly check all your lights, including brake lights, and ensure they are clean and functioning correctly. Ask a friend to help you check your brake lights.

2. Brakes

The braking system is paramount for safety, and any issues here will result in a failure. Common brake-related failures include:

• Brake Fluid: Low brake fluid level or contaminated fluid.
• Brake Lines: Corroded, leaking, or damaged brake lines or hoses.
• Brake Pads and Discs: Worn below the minimum thickness, cracked, or excessively corroded.
• Parking Brake: Not holding the vehicle effectively on a gradient, or being excessively stiff or loose.
• ABS Warning Light: If the ABS warning light is illuminated on the dashboard, it indicates a fault with the Anti-lock Braking System and will result in a failure.

Tip: Listen for any unusual noises when braking and be aware of any changes in the brake pedal feel. Have your brakes inspected if you notice any of these signs.

3. Tyres

Tyres are your car's only contact with the road, making their condition critical. Failures related to tyres include:

• Tread Depth: The legal minimum tread depth in the UK is 1.6mm across the central three-quarters of the tyre's width. Tyres with less than this will fail.
• Damage: Cuts, cracks, bulges, or other damage to the tyre sidewall or tread.
• Incorrectly Inflated: Tyres that are significantly under or over-inflated.
• Wrong Type: Tyres that are not suitable for the vehicle or are mismatched (e.g., different types of tyres on the same axle).
• Wheel Nuts/Bolts: Missing or loose wheel nuts or bolts.

Tip: Regularly check your tyre pressure and tread depth. Look for any visible damage. You can use a tread depth gauge or even a 20p coin to check the legal limit.

4. Steering and Suspension

Issues with steering and suspension can significantly affect a vehicle's handling and safety:

• Ball Joints: Worn or loose ball joints.
• Steering Rack: Leaking or excessively worn steering rack.
• Shock Absorbers: Leaking, damaged, or ineffective shock absorbers.
• Springs: Broken or corroded suspension springs.
• Power Steering: Leaks or faults in the power steering system.

Tip: Pay attention to any unusual noises when turning or driving over bumps, or if your steering feels loose or unresponsive.

5. Windscreen and Wipers

Visibility is key to safe driving:

• Windscreen: Cracks or chips in the windscreen within the driver's primary field of vision (a specific area of 430mm wide x 55mm high).
• Wipers: Wipers not clearing the windscreen effectively, or being damaged.
• Washers: Windscreen washer system not working or not providing sufficient fluid.

Tip: Ensure your windscreen is free from significant damage and that your wipers are in good condition and the washer fluid reservoir is topped up.

6. Exhaust Emissions

Environmental standards are a crucial part of the MOT:

• Excessive Smoke: Visible smoke from the exhaust, particularly if it's blue (oil burning), white (coolant leak), or black (fuel mixture issue).
• Emissions Levels: The vehicle's exhaust emissions exceeding the specified limits for its age and type of engine. This can be due to catalytic converter issues, engine problems, or sensor faults.

Tip: If you've noticed a change in your car's performance or exhaust noise, it might be worth having it checked by a mechanic before the MOT.

7. Other Common Failures

Beyond the major categories, several other issues can lead to an MOT rejection:

• Body Structure: Significant corrosion or damage to the vehicle's chassis, body panels, or suspension mounting points.
• Horn: The horn not working or not emitting a sound of sufficient volume.
• Fuel System: Leaks in the fuel system.
• Engine Warning Lights: Certain engine warning lights illuminated on the dashboard.
• Seats and Seatbelts: Damaged or faulty seatbelts, or seats not securely fixed.

Preparing Your Vehicle for its MOT

The best way to avoid an MOT rejection is to be proactive with your car's maintenance. Here are some key steps:

Pre-MOT Checks at Home

Before booking your MOT, conduct some basic checks yourself:

• Check tyre tread depth and look for any damage.
• Ensure all lights are working and clean.
• Test your windscreen wipers and washer fluid.
• Check your brake fluid level.
• Listen for any unusual noises from the engine, brakes, or suspension.
• Ensure your number plates are clean and securely fitted.

Regular Servicing

Regular servicing is the most effective way to catch potential problems before they become MOT failures. A qualified mechanic will check many of the components that are tested during the MOT as part of a routine service.

Choosing an Authorised Test Centre

Ensure you book your MOT at an official DVSA-approved test centre. These centres have trained testers who follow strict guidelines.

What Happens After an MOT Rejection?

If your vehicle fails its MOT, you will be given a 'Refusal of an MOT Test Certificate' (VT30) detailing the reasons for failure. You can still drive your car if the current MOT certificate is valid and the new failure does not represent a dangerous defect. However, you must get the necessary repairs done. You can have the repairs carried out at the test centre or elsewhere. If you choose to have repairs done elsewhere, you can present your vehicle for a partial re-test within 10 working days of the original test, and only the failed items will be re-inspected. If you present it after 10 working days, a full re-test is required.

MOT vs. Service: What's the Difference?

It's important to distinguish between an MOT and a car service. An MOT is a legal requirement to ensure your car meets minimum safety and environmental standards. A service is a preventative maintenance check that goes beyond the MOT requirements, often including oil changes, filter replacements, and checks on components that aren't part of the MOT test.

Frequently Asked Questions

Q1: Can I drive my car if it fails its MOT?

You can drive your car if its existing MOT certificate is still valid and the new failure does not constitute a dangerous defect according to the MOT tester. However, it's highly recommended to get any failures repaired as soon as possible.

Q2: How much does an MOT cost?

The maximum fee for an MOT test is set by the government. As of recent regulations, the maximum fee for a car is £54.85. However, many garages offer MOTs for less.

Q3: What if my car has a dangerous defect?

If your car has a dangerous defect, you must not drive it until it has been repaired. Driving a vehicle with a dangerous defect can result in prosecution.

Q4: What should I do if I think my car failed the MOT unfairly?

If you believe your car failed the MOT unfairly, you can appeal the decision to the DVSA. You must do this within one month of the original test date.

Conclusion

An MOT rejection can be a headache, but with regular maintenance and a good understanding of what the test entails, you can significantly increase your chances of passing first time. By proactively checking key components like tyres, lights, and brakes, and ensuring your car receives regular servicing, you not only prepare it for its MOT but also contribute to its overall safety and longevity on the road. Don't wait for the MOT to be your first inspection; make vehicle maintenance a consistent part of your driving routine.