Know Your MOT

MOT failure rate and common problems for the Leyland Aec D/D, and how to check your own car by registration.

Updated 05 September 2026.

23.6%fail rate

Leyland Aec D/D MOT failure rate

What a Leyland Aec D/D fails its MOT on, and the part that fixes each.

What it fails on, and why

Brakes69.2% of failures

Brake failures cover worn pads and discs, an imbalance between wheels, corroded or scored discs, or a binding caliper. Braking efficiency is measured on a rolling road, so a spongy or pulling brake shows up as a low reading.

Lamps & electrical23.1% of failures

Lighting is the single most common MOT failure and the cheapest to put right. A blown headlight, brake-light or number-plate bulb, a cracked lens, or a headlamp beam that points too high or low will all fail. Most are a two-minute bulb swap.

Suspension15.4% of failures

Suspension failures usually mean a worn or snapped coil spring, a leaking shock absorber, or play in a lower arm ball joint or bush. The tester checks for corrosion, fractures and excessive movement. A broken front spring is one of the most common failures on higher-mileage cars and is a straightforward replacement.

Exhaust & emissions15.4% of failures

Exhaust failures cover leaks, insecure mountings and emissions over the limit. A blowing exhaust, a failed lambda reading or a diesel that smokes beyond the limit will fail.

Seat belts7.7% of failures

Seat-belt failures are frays, cuts, corroded anchorages, or a belt that will not lock under a sharp pull or retract properly.

Other7.7% of failures

This covers a range of smaller items, from a non-working horn to a warning light left on.

The parts that fix each

If your car has just failed, you have 10 working days to fix the items and get a free partial retest. Confirm the exact fitment against your registration or VIN before buying.

For the brakes failure: Leyland Aec D/D brake pads and discsShop Leyland Aec D/D brake pads and discs on AmazonaffiliateFind Leyland Aec D/D brake pads and discs on eBayaffiliate
For the lamps & electrical failure: Leyland Aec D/D headlight and indicator bulbsShop Leyland Aec D/D headlight and indicator bulbs on AmazonaffiliateFind Leyland Aec D/D headlight and indicator bulbs on eBayaffiliate
For the suspension failure: Leyland Aec D/D suspension springs and shock absorbersShop Leyland Aec D/D suspension springs and shock absorbers on AmazonaffiliateFind Leyland Aec D/D suspension springs and shock absorbers on eBayaffiliate
For the exhaust & emissions failure: Leyland Aec D/D exhaustShop Leyland Aec D/D exhaust on AmazonaffiliateFind Leyland Aec D/D exhaust on eBayaffiliate
For the seat belts failure: Leyland Aec D/D seat beltsShop Leyland Aec D/D seat belts on AmazonaffiliateFind Leyland Aec D/D seat belts on eBayaffiliate

Other models

Leyland Aec Routemaster MOT failures20.9% failure rateLeyland Aec Reliance MOT failures14.8% failure rateLeyland Aec Bus MOT failures12.0% failure rateFord Fiesta MOT failures27.1% failure rate

Questions and answers

What is the MOT failure rate of the Leyland Aec D/D?

It fails 23.6% of its MOT tests across the DVSA record, from 55 tests.

What do these cars fail their MOT on most?

The most common failure area is brakes, at 69.2% of this model's failures.