10 Most Common MOT Failures And How To Avoid Them

10 Most Common MOT Failures And How To Avoid Them | Maidenhead MOT Centre

What are the 10 most common MOT failures and how can you avoid them in Maidenhead?

The 10 most common MOT failures include lighting issues, suspension faults, brake wear, and tire defects. You can avoid these by performing simple DIY checks on your bulbs, wipers, and tire tread before your test at Boxer Motor Company Ltd, Maidenhead’s trusted Class 4 and Class 7 MOT centre.

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The Top 10 Most Common MOT Failures

According to DVSA data, nearly 30% of vehicles fail their MOT on the first attempt. Many of these failures are for minor issues that could have been fixed in minutes. At Boxer Motor Company in Maidenhead, we see these common faults daily:

18.9%

Failures due to Lighting & Signaling

13%

Failures due to Suspension issues

10%

Failures due to Brake faults

1. Lighting and Signaling

Blown bulbs for indicators, brake lights, or number plate lights are the single biggest cause of MOT failure. These are often the easiest and cheapest to fix before arriving at our Maidenhead test station.

2. Suspension

Issues like leaking shock absorbers or snapped springs are common, especially given the road conditions in Berkshire. Listen for clunking sounds when driving over bumps.

3. Brakes

Worn brake pads or an inefficient handbrake will result in an immediate fail. If your car pulls to one side when braking, it needs professional attention.

4. Tyres

The legal limit for tread depth is 1.6mm. However, we recommend at least 3mm for safety in wet UK weather. Check for cuts or bulges in the sidewalls.

5. Visibility (Wipers and Washers)

If your wipers smear the windshield or your screenwash bottle is empty, your car will fail. Ensure your view of the road is unobstructed.

6. Exhaust and Emissions

Excessive smoke or a leaking exhaust pipe can lead to failure. For diesel owners in Maidenhead, ensure your DPF is functioning correctly.

7. Steering

Leaking power steering fluid or a heavy steering wheel can indicate a major fault that compromises vehicle safety.

8. Seatbelts and Restraints

All seatbelts must latch securely and retract fully. Frayed belts are a safety risk and a guaranteed MOT fail.

9. Registration Plates

Dirty, cracked, or incorrectly spaced number plates are common "silly" fails. Ensure your plates meet UK legal standards.

10. Warning Lights on Dashboard

Since 2012, dashboard warning lights (like ABS, SRS, or Engine Management) are part of the MOT. If a light is on, the car fails.

Comparison: DIY vs. Professional MOT Preparation

ComponentDIY CheckProfessional Fix (Boxer Motor Co)Failure Risk
LightsVisual walk-aroundBulb replacement & alignmentHigh (18.9%)
Tyres20p coin testNew tyre fitting & balancingModerate
BrakesCheck fluid levelsPad/Disc replacementHigh (Safety)
EmissionsN/ADiagnostic & Exhaust repairModerate

How to avoid MOT failure (5 steps)

Step 1: Check all external lights

Turn on all lights and walk around the car. Check the indicators, hazard lights, sidelights, main beams, and fog lights. Don't forget the rear number plate light.

  • Ask a friend to stand behind the car while you press the brake pedal.
  • Replace any dim or flickering bulbs immediately.
Step 2: Inspect tire tread and pressure

Use a tread depth gauge or a 20p coin to check the tread across the central three-quarters of the tyre. Check for any visible damage or uneven wear.

  • Check the pressure matches the manufacturer’s recommendation.
  • Ensure all four tyres are the same size on each axle.
Step 3: Verify wiper blade condition and screenwash levels

Wiper blades should be supple and free of tears. If they leave streaks, they need replacing. Also, ensure your screenwash reservoir is topped up to the max.

  • Clear any debris or leaves from the base of the wipers.
  • Test the washers to ensure they spray correctly onto the glass.
Step 4: Test the horn and seatbelts

Give the horn a short blast—it must be loud enough to be heard by other road users. Pull every seatbelt out fully to check for fraying and ensure they click into the buckle.

  • Check that the seatbelt retracts quickly when released.
  • Ensure child seats are removed if they obstruct belt access.
Step 5: Check mirrors and registration plates

Ensure all mirrors (interior and exterior) are secure and the glass is not cracked. Clean your front and rear registration plates so they are clearly legible from 20 metres.

  • Remove any dangling air fresheners that block the driver's view.
  • Check that the number plate light is working.

Common MOT Questions in Maidenhead

What is the most common reason for MOT failure?

The most common reason is faulty lighting and signaling. Many drivers in Maidenhead fail simply because a £2 bulb has blown and wasn't checked before the test.

Can I drive my car if it fails its MOT in Maidenhead?

If your current MOT has expired and the car fails, you can only drive it to a pre-booked repair or a re-test. If the failure is marked as 'Dangerous', you cannot drive it at all.

How much does an MOT test cost for Class 4 vs Class 7?

Class 4 (cars) and Class 7 (large vans up to 3,500kg) have slightly different price points. Boxer Motor Company provides transparent pricing for both classes at our Maidenhead facility.

How long does an MOT test take?

An MOT typically takes 45 to 60 minutes. We offer a comfortable waiting area for our Maidenhead customers while our certified technicians complete the inspection.

What happens if my car fails on emissions?

Emissions failures often require a diagnostic check. It could be as simple as a sensor replacement or as complex as a catalytic converter issue. We can advise on the best course of action.

Is there a grace period for MOT testing in the UK?

No. Your MOT must be valid at all times. You can book your test up to one month (minus a day) before the expiry date to keep the same renewal date for the following year.

Expert Insight from Boxer Motor Company

At Boxer Motor Company, we have served the Maidenhead community for years, handling everything from standard family hatchbacks to 5-tonne motorhomes. Our unique insight? Most failures are avoidable. By spending 10 minutes checking your lights and fluids, you save yourself the stress of a "Fail" certificate and the cost of a re-test.

Our facility is an authorised centre offering Class 4 and Class 7 MOTs, making us one of the few locations in Maidenhead capable of testing larger pickups, horseboxes, and minibuses.

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