Roughly one in three UK cars fails its MOT first time — and the bulk of those failures are for tiny, fixable things you can spot in your own driveway. Run through this checklist the evening before your test and you'll cut the odds dramatically.
A pre-MOT check is an inspection of the items an MOT tester will look at, carried out before the real test so you can fix faults on your own terms instead of paying for a re-test. It covers lights, tyres, wipers, washers, brakes, seatbelts, mirrors, screen damage, horn, warning lights, exhaust and fluid levels.
Doing it yourself costs nothing beyond a set of bulbs or a bottle of screenwash; a garage pre-MOT inspection is typically £20–£40 in the UK. A Class 4 MOT is £54.85, so a ten-minute driveway check the night before almost always pays for itself.
Blown bulbs are the single most common MOT failure in the UK. Walk round the car with a helper pressing the pedal and indicators: sidelights, dipped beam, main beam, front and rear fogs, indicators, hazards, brake lights (all three including the high-level), reverse, and the number-plate lights.
Anything dim, flickering or out gets replaced. LED-converted bulbs in a halogen reflector will fail — refit the original spec for the test.
Lift each blade and feel the rubber edge — any splits, smears or chunks missing and it's a fail. Top up the washer bottle and check every jet sprays cleanly onto the swept area. Don't forget the rear wiper and washer if fitted. A £10 pair of blades the night before saves a re-test fee.
Legal minimum is 1.6 mm across the central three-quarters of the tread, all the way round the tyre. Use a 20p coin — if the outer band of the coin is visible when slotted into the tread, you're under.
Check the sidewalls for bulges, cuts or perishing, and set the pressures to the door-sticker figure cold. Mismatched sizes across an axle is an automatic fail.
Cold engine, key on, pump the brake pedal — it should firm up within two or three pumps and stay there. A pedal that sinks slowly to the floor is a master cylinder fail. The handbrake should hold the car on a moderate slope by the fourth or fifth click; if you're running out of travel it needs adjustment before test day.
Any chip larger than 10 mm in the driver's swept area, or 40 mm anywhere else on the screen, is a fail. Check both door mirrors are secure and the glass isn't cracked. Both number plates must be clean, legal-spaced font and securely fixed — a flapping rear plate fails the test.
Pull each belt out fully and let it retract — it should pull back smoothly and lock under a sharp tug. Inspect the webbing for fraying, cuts or burns. Test every buckle clicks home and releases cleanly. Rear belts count too, even on a car that rarely carries passengers.
Press the horn — it should sound a single continuous note, not a tune or an air-horn. Start the engine and watch the dash: any warning light that stays on after start-up (EML, ABS, airbag, ESP, brake) is a fail under the 2018 MOT rules. Check the VIN and registration on the V5 match the plates and the chassis stamp.
Engine oil between min and max on the dipstick, coolant at the cold mark in the expansion bottle, brake fluid above MIN, washer bottle full. Low brake fluid won't fail directly but the warning light will — and a low coolant level can mean the engine runs hot during the emissions test and fails on smoke.
Start the engine cold and listen at the back. A blow from the manifold, a rattle from a heat shield, or smoke from the tailpipe all point to test-day trouble. On diesels, a deleted DPF is an instant fail — get that put back to standard before booking in.
The driver's seat must adjust and lock in place, the seatbelt anchor points must be solid, and the airbag warning light must extinguish after start-up. Clear any clutter from the dashboard that obstructs the view, and check the boot floor lifts cleanly to expose the spare-wheel well — testers will look.
An inspection of everything an MOT tester examines, done before the test so faults can be fixed cheaply instead of causing a failure. It covers bulbs, tyres, wipers, washers, brakes, seatbelts, mirrors, screen damage, horn, warning lights, fluid levels and the exhaust.
Doing it yourself costs nothing beyond a bulb or a bottle of screenwash. A garage pre-MOT inspection is typically £20–£40 in the UK, and some garages fold it into the MOT itself.
The DVSA-capped fee for a Class 4 car is £54.85, which is what Bob's charges. A re-test within 10 working days is free if the car is left at the garage.
Lighting and signalling — about 18% of all failures — followed by suspension, brakes and tyres. The first three checks on this list catch most avoidable failures.
Yes. Since the 2018 rule changes, any illuminated MIL (engine, ABS, airbag, stability, brake warning, power steering, EPB) is a major failure. Get fault codes read before booking.
Only if you have a pre-booked MOT appointment, and the car must still be roadworthy. Driving without an MOT can cost you points and a fine.
Up to one calendar month minus a day before the current certificate expires, keeping the original renewal date. Earlier than that and you lose the days.
You get a VT30 failure document listing the defects. Leave the car with the testing station and if they fix the failures within 10 working days the re-test is free. Drive it away and the re-test is chargeable.
The evening before, or a couple of days before if you want time to order a part. A blown bulb or a worn wiper is far cheaper to fix on the driveway than after the tester has written it on a VT30.
Bob's Mechanical Repairs — independent family-run garage in Birnam, Dunkeld, Perthshire. Call 01350 727 276 or email [email protected].