10 Things to Check on Your Car Before an MOT to Avoid a £20 Retest Fee (or Overpaying for Simple Fixes)

Failing an MOT for something minor can be frustrating and costly. Here’s how to avoid unnecessary failures and save money by checking these simple things yourself before heading to the MOT garage.

1. Tyres – Tread, Pressure & Condition (10.4% Fail Here)

Check that your tyres aren’t excessively worn, underinflated, or damaged. The legal minimum tread depth is 1.6mm—use the 20p test (Google it if you’re unsure). Replacing tyres before your MOT, rather than in a last-minute panic, will almost always save you money.

2. Lights – Check They All Work (29.6% Fail Here)

Turn on your headlights, indicators, brake lights, fog lights, and number plate lights. Get someone to check for you or use reflections in windows. A failed bulb is one of the easiest things to fix before an MOT.

3. Seat Belts – Test Every One (2.2% Fail Here)

Ensure all seat belts, including the rear middle one, work properly and retract as expected. If you have kids who snack in the car, check for food or debris clogging the belt mechanism and use a vacuum to clear.

4. General Cleanliness – Don’t Let Them Refuse the Test

MOT testers can refuse to test a car that’s excessively dirty or full of clutter. Give it a quick clean inside and out, especially around the driver’s area and footwells.

5. Number Plates – Clean & Clearly Visible (0.9% Fail Here)

Make sure your number plates are readable and securely attached. A dirty or damaged plate can lead to an unnecessary failure.

6. Fluid Levels – Top Them Up

Check and top up your oil, brake fluid, screen wash, and coolant. If any warning lights are on due to low levels, it could lead to an MOT failure.

7. Horn – Simple but Essential

Press your horn—if it doesn’t work, it’s an instant fail. A faulty horn is usually an easy and cheap fix, so don’t overlook it.

8. Windscreen – Chips, Cracks & Visibility (8.7% Fail Here)

Clean your windscreen thoroughly, especially in the driver’s line of sight. Any chip or crack larger than 10mm in the driver’s view (or 40mm elsewhere) is a fail. Get chips repaired before they turn into bigger cracks.

9. Suspension – Listen for Issues in Advance (20.2% Fail Here)

Suspension faults are one of the top reasons for MOT failures. If you notice knocking noises, a bumpy ride, or uneven tyre wear, get it checked before MOT week.

10. Brakes – Listen, Feel & Inspect (17.2% Fail Here)

A huge number of failures are due to brake issues. Listen for squealing or grinding, feel for pulling to one side, and visually inspect for excessive rust or uneven wear. Fixing brake problems ahead of time avoids last-minute, expensive repairs.

Our Final Thoughts:

Most of these checks should be done regularly, not just before an MOT. But judging by the state of some cars on the road (especially some taxis), it’s clear that many people don’t bother. A few simple checks could save you time, money, and hassle—so don’t skip them! You can also check the full checklist here

Data from the AA.