Top 10 MOT Fails UK Drivers Face (and How to Avoid Them)
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🚗 Top 10 MOT Fails UK Drivers Face (and How to Avoid Them)
Learn the most common MOT fails UK drivers face — and how to prevent them. A certified MOT tester shares real-world tips to help you pass first time.
💬 Introduction
Every year, millions of cars in the UK fail their MOT for simple, avoidable reasons. After nearly three decades as an MOT tester, I can tell you that most failures have nothing to do with major mechanical issues — they come down to basic checks that drivers overlook.
In this guide, I’ll break down the top 10 most common MOT fails, explain why they happen, and show you exactly how to avoid them — saving you time, money, and stress.
🔧 1. Lights & Indicators
The number one MOT fail across the UK — blown bulbs, cracked lenses, or incorrect colour lights.
How to avoid it:
- Check all bulbs weekly (front, rear, brake, number plate, indicators).
- Make sure the colours are correct — no white indicators or overly tinted lights.
- Ask someone to help check brake lights while you press the pedal.
💡 Pro tip: Carry spare bulbs — it’s one of the cheapest fixes you can make yourself.
🧯 2. Tyres
Tyres fail MOTs every day due to low tread depth or visible damage. The legal minimum is 1.6mm across the central three-quarters.
How to avoid it:
- Use a tread gauge or a 20p coin — the border should disappear inside the groove.
- Check for cuts, bulges, or exposed cords.
- Ensure all tyres are the same size per axle.
🛠 Recommended Tool: Digital Tyre Tread Gauge – Amazon UK
🚨 3. Brake Issues
Uneven braking or worn pads will cause an immediate fail.
How to avoid it:
- If you hear grinding or squealing, get it checked before your MOT.
- Uneven braking often shows up as pulling to one side.
- Brake fluid should be topped up and changed every 2 years.
💨 4. Emissions
Modern diesels and petrol cars fail due to emissions outside legal limits.
How to avoid it:
- Give your car a good 20-minute motorway run before your MOT.
- Make sure your air filter and oil are clean.
- Use a fuel additive occasionally to clear carbon buildup.
🪟 5. Windscreen Damage
Any chip or crack larger than 10mm in the driver’s view = instant fail.
How to avoid it:
- Fix chips early before they spread.
- Keep washer jets clean and fluid topped up.
🪞 6. Mirrors
Loose, cracked, or missing mirrors are an easy fail.
How to avoid it:
- Check that all mirrors are secure and intact.
- Make sure they provide a clear view of the rear and sides.
🪫 7. Battery & Wiring
A loose battery or exposed wiring is an MOT red flag.
How to avoid it:
- Ensure terminals are tight and corrosion-free.
- Secure the battery with its proper clamp.
🪑 8. Seatbelts
Any frayed, cut, or non-functioning seatbelt will cause a fail.
How to avoid it:
- Pull belts fully out and check for wear.
- Ensure they retract properly and latch securely.
🧠 9. Registration Plate Issues
Incorrect fonts, spacing, or unreadable plates are instant fails.
How to avoid it:
- Keep plates clean and legible.
- Ensure font and spacing comply with DVLA standards.
🚘 10. Suspension & Steering
One of the most common hidden MOT fails.
How to avoid it:
- Listen for knocks or clunks over bumps.
- Get a pre-MOT check if your car feels unstable.
✅ Summary Table
| MOT Fail | Simple Fix |
|---|---|
| Lights | Check bulbs weekly |
| Tyres | Minimum 1.6mm tread |
| Brakes | No grinding or pulling |
| Emissions | Drive before MOT |
| Windscreen | Repair small chips |
| Mirrors | Keep clean & secure |
| Battery | Tight connections |
| Seatbelts | Check retract & latch |
| Plates | DVLA compliant |
| Suspension | Pre-check if unsure |
🧰 Need Expert Help Before Your MOT?
If you’re not sure about something — don’t risk a fail. Book a remote vehicle diagnostic session with me and I’ll walk you through your MOT prep live via video.
📅 Book a 30-Minute MOT Diagnostic – £29.99
📺 Watch Our MOT Tips on YouTube
🎥 Visit AutoAdvice Online YouTube Channel
💡 Final Thoughts
An MOT fail isn’t bad luck — it’s usually preventable. Take 15 minutes to check your car before the test, and you’ll avoid 90% of the reasons drivers fail.
With a little preparation — and the right advice — you can keep your car safe, legal, and on the road.
Want to avoid the most common MOT mistakes? Check out our Step-by-Step MOT Checklist to get your car ready and pass first time.
❌ Failed your MOT? Don’t worry — it happens more often than you’d think. Check out our Step-by-Step Guide on What to Do If Your Car Fails Its MOT for practical advice from a certified MOT tester on what to fix first and how to get back on the road quickly.