Understanding MOT Failures

The MOT test, or Ministry of Transport test, is an annual check that ensures your vehicle meets the minimum safety and environmental standards required by law in the United Kingdom. While many vehicles sail through their MOT with flying colours, a significant number fail each year. Understanding what constitutes an MOT fail is crucial for any vehicle owner, not only to avoid potential fines and legal issues but also to ensure the roadworthiness and safety of your car.

Common Reasons for MOT Failure

MOT failures can stem from a wide array of issues, ranging from minor cosmetic faults to critical mechanical problems. The Driver and Vehicle Standards Agency (DVSA) categorises defects into three main types: Dangerous, Major, and Minor. A vehicle will fail its MOT if it has any 'Dangerous' or 'Major' defects. Minor defects are noted on the MOT certificate but will not cause a fail.

Visibility: A Clear View is Key

Visibility is paramount for safe driving. Several components relate to a vehicle's ability to see and be seen:

• Windscreen: Cracks or chips in the windscreen, particularly in the driver's line of sight, are a common reason for failure. The DVSA specifies that damage within a 4mm band along the edge of the windscreen or in the 'Zone A' (the area swept by the wipers) larger than 10mm will result in a fail.
• Wipers and Washers: Ineffective windscreen wipers that don't clear the screen properly, or a lack of windscreen washer fluid, can lead to an MOT failure.
• Lights: All lights must be in working order and correctly aimed. This includes headlights (both high and low beam), taillights, brake lights, indicator lights, and fog lights. A burnt-out bulb, a cracked lens, or misaligned headlights will cause a fail. The colour of the lights is also checked; for example, white is required for headlights and red for taillights.

Braking System: The Heart of Safety

The braking system is arguably the most critical safety component of any vehicle. Any issue that compromises braking performance will result in an MOT fail:

• Brake Fluid: Insufficient or contaminated brake fluid can lead to poor braking performance.
• Brake Pad and Disc Wear: Worn-out brake pads or discs below the legal minimum thickness are a definite fail.
• Brake Hoses and Pipes: Corroded, leaking, or damaged brake hoses and pipes will cause the vehicle to fail.
• Brake Performance: During the test, the efficiency of the braking system is measured. If the brakes do not meet the required stopping power, the vehicle will fail. This can be due to a combination of the above factors.

Tyres and Wheels: Grounding the Vehicle Safely

The condition of your tyres and wheels directly impacts grip, stability, and braking:

• Tyre Tread Depth: The legal minimum tread depth for car tyres in the UK is 1.6mm across the central three-quarters of the tread width. Tyres with less tread will fail.
• Tyre Damage: Cuts, bulges, or exposed cords on the tyre sidewall or tread are considered dangerous and will lead to a fail.
• Tyre Pressure: While not directly tested for accuracy, incorrect tyre pressures can lead to uneven wear, which may be picked up.
• Wheel Condition: Damaged or corroded wheels that could compromise safety may also cause a fail.
• Wheel Bearings: Excessive play in the wheel bearings will result in a fail.

Steering and Suspension: Maintaining Control

These systems are vital for maintaining control of the vehicle:

• Steering System: Issues such as worn steering components (e.g., track rod ends, ball joints), excessive play in the steering wheel, or a leaking steering rack will cause a fail.
• Suspension Components: Damaged or excessively worn shock absorbers, springs, or suspension arms are a common cause of failure. Any sign of leaks from shock absorbers is also a fail.

Exhaust Emissions: Environmental Responsibility

Vehicles are tested to ensure they meet emission standards:

• Exhaust Emissions: If your vehicle emits too much of certain pollutants, it will fail. This is particularly relevant for diesel vehicles, which are checked for visible smoke. The specific limits vary depending on the vehicle's age and fuel type.
• Exhaust System: A leaking, corroded, or damaged exhaust system, or one that is not securely fitted, will also result in a fail.

Bodywork and Structure: The Vehicle's Integrity

The structural integrity of the vehicle is assessed:

• Corrosion: Excessive corrosion on the vehicle's structure, including the chassis, suspension mounts, and body panels, can lead to a fail. The tester will look for rust that has significantly weakened these areas.
• Damage: Significant damage to body panels, bumpers, or doors that could be a safety hazard will also cause a fail.
• Sharp Edges: Any sharp edges or projections on the bodywork that could injure pedestrians or other road users are a reason for failure.

Other Potential Failure Points

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

• Seats: A seat that is not securely fixed to the vehicle's structure can cause a fail.
• Seatbelts: Seatbelts must be in good condition, free from damage, and function correctly. Any faulty seatbelt will result in a fail.
• Horn: The horn must be operational and of the correct type.
• Fuel System: Leaks in the fuel system are a serious safety hazard and will lead to a fail.
• Doors: Doors must open and close correctly, and the mechanism for opening them from both the inside and outside must be functional.
• Registration Plates: Illegible or non-compliant registration plates are a fail.
• Speedometer: The speedometer must be visible and functioning correctly.
• Battery: While the battery itself is not tested for its charge, it must be securely mounted.

Preparing Your Vehicle for the MOT

The best way to avoid an MOT fail is through regular maintenance and pre-emptive checks. Here are some tips:

What Happens After an MOT Fail?

If your vehicle fails its MOT, you will be given a 'Refusal of an MOT Test Certificate' document, which outlines the reasons for the failure. You can continue to drive your vehicle until the expiry date of your current MOT certificate, provided the defects are not classed as 'dangerous'. If the defects are dangerous, you cannot drive the vehicle until the necessary repairs have been made. You have a limited time (usually 10 working days) to have the repairs carried out and the vehicle retested. You can choose to have the repairs done at the original testing station or elsewhere. If you have the repairs done at the original station, you may only need a partial retest, which can sometimes be free of charge depending on the nature of the failure and the time elapsed.

Frequently Asked Questions

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

You can drive your car if it fails its MOT, but only if the current MOT certificate is still valid and the faults are not deemed 'dangerous'. If the faults are dangerous, you must not drive the vehicle until it has been repaired. Driving a vehicle with dangerous faults can lead to an immediate fine and penalty points.

Q2: What is the difference between a 'Major' and a 'Dangerous' defect?

A 'Dangerous' defect is one that poses a direct and immediate risk to road safety or has a serious impact on the environment. A 'Major' defect is one that does not pose an immediate risk but is still significant enough to require repair. Both will cause an MOT fail.

Q3: How long do I have to get my car repaired after an MOT fail?

You can drive your car until the current MOT expires, as long as the failure items are not 'dangerous'. You should aim to get the repairs done as soon as possible. If the current MOT has expired, you will need to get the car repaired and have it pass the MOT before you can legally drive it on public roads.

Q4: Does the MOT tester have to tell me why it failed?

Yes, the MOT tester is legally obliged to provide you with a detailed report explaining why your vehicle failed the test, listing all the defects found. This report is essential for carrying out the necessary repairs.

Q5: What happens if my car passes the MOT with a minor fault?

If your car has minor faults, they will be listed on the MOT certificate as 'advisories'. These are not reasons for the vehicle to fail the test, but they highlight areas that may need attention in the future to prevent them from becoming more serious problems. It's wise to address advisories promptly to maintain your vehicle's condition and avoid future MOT failures.

In conclusion, understanding the common reasons for an MOT fail is the first step towards ensuring your vehicle remains safe and compliant on UK roads. Regular checks, proactive maintenance, and addressing any advisories promptly will significantly increase your chances of a successful MOT test and contribute to a safer driving experience for everyone.

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