Why Cars Fail Their MOT: The Most Common Reasons

14 October 2025 · 5 min read

Lights and signalling top the list

Year after year, lighting and signalling faults are among the most common reasons a car fails its MOT. A blown sidelight bulb, a cracked indicator lens or a number plate light that has stopped working is enough to fail the test.

Walk round your car with someone pressing the brake pedal and flicking each light on. It takes five minutes and saves you a failure for something that costs a few pounds to fix.

Suspension, brakes and tyres

Worn suspension parts such as ball joints, bushes and broken coil springs are a frequent failure on cars that use our local roads every day. Potholes speed this up, and a broken spring can be hard to spot without the car on a ramp.

Brakes fail when pads or discs are worn, a brake pipe is corroded, or the car pulls under braking. Tyres fail for low tread, cuts, bulges or the wrong size on one axle. Check your tread depth and look for damage on the inner edges too.

Visibility: wipers, washers and windscreen

Split wiper blades, an empty washer bottle and chips in the driver's line of sight all cause failures. A chip larger than 10mm in the area swept by the wiper in front of the driver, or 40mm elsewhere in the swept area, is a fail.

Top up the washer fluid and replace tired wiper blades before the test. It is the cheapest MOT pass you will ever get.

Book your MOT in Brierley Hill

We are a DVSA MOT test centre on Mount Pleasant. If your car fails, we explain each item in plain English and give you a clear quote, and most repairs can be done here so you can be retested quickly.

Call us on 01384 936310 to book. We are open Monday to Friday, 09:00 to 17:00.

Book an MOT in Brierley Hill →

Need help with your car?

Call Brierley Hill Auto Centre for clear advice and a fast booking.

Call 01384 936310