Common Reasons Cars Fail an MOT Test and How to Avoid Them

Common MOT failures often catch drivers off guard. You think your car is ready then it fails. This practical guide breaks down the eight most common MOT failure areas: brakes, tyres, lights, wipers, windscreens, suspension, exhaust, and seatbelts. 

You’ll learn how to inspect each one yourself before booking your MOT Check, along with simple tips to fix issues early. We’ve also included a quick pre-test checklist and answers to common questions to help you pass your MOT for the first time with confidence. 

Brake System Issues

Brakes are a top reason for failure. Worn brake pads are a common reason. The tester checks brake performance on rollers.

Check these before your MOT:

• Listen for grinding or squeaking noises.

• Feel for a spongy pedal.

• Test the handbrake on a hill.

Fix any issues early. Worn brake pads are cheap to replace. A brake failure is dangerous and costly.

Tyre Problems

Tyres must be in good condition. The legal tread depth is 1.6mm. Use a 20p coin to check it.

Look for these tyre issues:

• Cuts or bulges in the sidewall

• Uneven wear across the tread

• Different brands on the same axle

Tyre tread depth below the limit is a fail. Replace damaged tyres before your test.

Lights and Indicators

Lights must work properly. Faulty headlights are a common failure. Brake lights not working will also fail you.

Check all these lights:

• Headlights (dip and main beam)

• Brake lights (get someone to help)

• Indicators (front and rear)

• Fog lights (if fitted)

A bulb costs a few pounds. A failure costs time and money. Faulty headlights are easy to fix.

Windscreen and Wipers

The windscreen must be clear. Any damage larger than 10mm fails. Chips in the driver's view are not allowed.

Check these wiper issues:

• Wipers that smear or streak

• Torn or split rubber blades

• Wipers that do not clear the screen

Replace worn blades before the test. Windscreen damage should be repaired early. Most insurance covers chip repairs for free.

Visibility Issues

The driver's view must be clear at all times. Stickers or phone holders can block the view.

Common visibility problems:

• Cracks in the danger zone (within the wiper sweep)

• Heavy window tint on the windscreen

• Items hanging from the rearview mirror

Visibility issues are easy to miss. Clean your windows inside and out. Remove anything that blocks your view.

Suspension and Steering

Worn shock absorbers affect braking and handling. Knocking sounds mean suspension problems.

Signs of suspension trouble:

• The car dips when braking

• The car leans when turning

• Uneven tyre wear

Get a pre-MOT inspection if you are unsure. Fixing the suspension is cheaper than a retest.

Exhaust and Emissions

Excessive smoke means engine trouble. A leaking exhaust is a fail. Ensure that the check engine light is off.

Check these before your MOT:

• Blue smoke (burning oil)

• Black smoke (too much fuel)

• White smoke (coolant leak)

Drive your car for 20 minutes before the test. A warm engine produces cleaner emissions.

Seatbelts and Seats

Seatbelts must retract and latch properly. Frayed or cut belts fail. The driver's seat must adjust securely.

Quick seatbelt check:

• Pull the belt sharply. It should lock.

• Check for cuts or frayed edges.

• Test every belt in the car.

Seatbelt issues are cheap to fix. A failed belt means a failed MOT.

Quick Checklist Table

How to Avoid a Fail

A little prep saves time and money. Follow these simple steps:

• Do a pre-MOT check yourself.

• Fix small issues before the test.

• Use a trusted local garage.

• Book your MOT a month early.

Common MOT failures are often easy to prevent. A few minutes of checking can save you a retest fee.

Final Thoughts

Passing your MOT is not luck. It is preparation. A few minutes of checking can save you a retest fee. Fix these small issues before they turn into bigger ones. A clean car with working lights and good tyres is half the battle. Common MOT failures are easy to prevent. Do not let a blown bulb or worn wiper ruin your day. Check early. Fix early. Pass with confidence.

FAQs

Q: What is the typical cause for MOT failure?

A: Faulty lights and brakes are the top reasons. Worn tyres also cause many failures. A common MOT failures checklist helps you catch these issues early.

Q: Can I drive with worn brake pads before my MOT?

A: You can, but it is not safe. Worn pads reduce stopping distance. Replace worn brake pads before your test to avoid a fail.

Q: How much tyre tread depth is legal in the UK?

A: The legal minimum is 1.6mm across the centre three-quarters. To check your tyre tread depth, you can use a 20p coin. Below this limit is a fail.

Q: Will a cracked windscreen fail an MOT?

A: Yes, if the crack is larger than 10mm. Any chip in the driver's view also fails. Repair windscreen damage before your test.

Q: Do my headlight bulbs need to match?

Yes, both headlights must work and aim correctly. A mismatched or dim bulb can fail. Faulty headlights are an easy fix.