Common MOT Failures in the UK and How to Avoid Them

Common MOT Failures in the UK and How to Avoid Them

Every year, millions of UK vehicles go through their MOT. Surprisingly, a significant number fail on the first attempt. The frustrating part? Many of the most common reasons are simple problems you could fix yourself before the test.

Knowing what testers look for — and spending ten minutes on basic checks — can save you time, money, and the hassle of a retest.

1. Lighting and Signalling (The Most Common Failure)

Lights and indicators account for nearly 30% of all MOT failures year after year. It's the single biggest reason cars fail, and ironically the easiest to prevent.

What Fails:

• Blown bulbs in headlights, taillights, brake lights, or indicators.
• Misaligned headlights (often from fitting a bulb incorrectly).
• Cracked or heavily oxidised headlight lenses that distort the beam.
• Number plate lights not working.

How to Avoid It:

Spend five minutes checking all your lights. Turn on everything — hazards, fog lights, the lot — and walk around the car. For brake and reverse lights, ask a friend to help or back up against a reflective surface like a window. A blown bulb costs a few quid and takes minutes to swap. An MOT failure means a retest.

2. Suspension and Steering

Suspension parts take a beating on the UK's potholed roads. This is the second most common category for MOT failures.

What Fails:

• Leaking shock absorbers.
• Snapped coil springs.
• Worn suspension bushes or ball joints.
• Excessive play in the steering rack or track rod ends.

How to Avoid It:

You can't easily inspect bushes without a ramp, but you can spot warning signs. If your car clunks or knocks over bumps, or the steering feels vague or pulls to one side, something's up. Push down hard on each corner — the car should settle quickly without bouncing more than once or twice. If it keeps bouncing, the shocks are likely worn.

3. Brakes

Brakes are critical for safety, and testers are thorough when checking them.

What Fails:

• Worn brake pads (below 1.5mm, though many fail well before that).
• Excessively worn, scored, or warped brake discs.
• Corroded or leaking brake pipes.
• A handbrake that doesn't hold or travels too far.

How to Avoid It:

Listen for grinding or squealing when braking — that usually means worn pads. If the steering wheel or brake pedal vibrates under braking, your discs may be warped. Look at the discs through the wheels; they should be smooth and shiny, not deeply scored or rusty. Check the handbrake travel — if it clicks more than a few times before holding on a hill, it needs adjusting.

4. Tyres

Tyres are your only contact with the road. Testers check them carefully.

What Fails:

• Tread depth below the legal minimum of 1.6mm across the central three-quarters.
• Cuts, bulges, or tears in the sidewall.
• Exposed cords.
• Under-inflated tyres (this affects brake testing equipment).

How to Avoid It:

Use the 20p test: push a 20p coin into the main tread grooves. If the outer band of the coin is visible, your tyres may be below the limit. Check the whole tyre for uneven wear — that could mean alignment issues. Look at the sidewalls for damage. Make sure all tyres are inflated to the manufacturer's recommended pressures before the test.

5. Driver's View of the Road

The MOT makes sure your visibility isn't compromised.

What Fails:

• Cracks or large chips in the windscreen, especially in the driver's direct line of sight (Zone A). Anything larger than 10mm in Zone A, or 40mm elsewhere, is a failure.
• Worn or torn windscreen wipers that don't clear properly.
• Empty windscreen washer fluid.
• Items blocking the view, like badly placed sat-navs or dangling air fresheners.

How to Avoid It:

Another easy fix. Top up your washer fluid before the test. Check your wiper blades — if they streak or judder, replace them. Remove suction-mounted devices and air fresheners from the windscreen before you arrive. If you have a chip, get it repaired before it turns into a crack that needs a full replacement.

Prevention Starts with Knowledge

Knowing which problems your specific make and model is prone to can help you focus your pre-MOT checks. If a particular car has a reputation for failing on suspension bushes or emissions, you can address those known weak points before the test — rather than discovering them as a surprise failure. Check our common problems database to see what other owners of your car report most.

Conclusion

Failing an MOT is annoying, but it's often avoidable. Ten minutes of basic checks — lights, tyres, wipers, washer fluid — can catch the simple stuff before the test date. Run a free MOT history check on your registration to review past advisories and see what testers flagged before — that's often the best predictor of what might fail next. The combination of prevention and awareness saves you the hassle of a retest and keeps your car safer on the road all year.