Mercedes Benz S Class MOT Failures
An analysis of 172,840 real DVSA MOT tests on the Mercedes Benz S Class — what fails, how often, and how that compares to every other car on UK roads.
Where the Mercedes Benz S Class fails its MOT
The single biggest MOT failure point on the Mercedes Benz S Class is any fracture or welding defect on a wheel — this model is 17 times more likely to fail on this item than the average car on UK roads. That makes it a significant weak point for anyone buying or owning this model. Across 172,840 MOT tests, 0.46% of all Mercedes Benz S Class tests recorded this as a failure.
Wheel-related failures include cracked alloys, damaged wheel studs, and bearing play. Listen for rumbling at speed (wheel bearings) and check for any visible cracks around alloy spokes.
Other notable weak points include transmission shaft flexible coupling deteriorated (21x the fleet average), suspension pin, bush or joint worn (24x the fleet average), front or rear fog lamp with a multiple light so... (106x the fleet average), and emissions failure (33x the fleet average). These ratios compare the Mercedes Benz S Class's failure rate on each item against the national average for all cars tested — a ratio of 10x means this model fails ten times more often than a typical car.
The failures span 6 categories: Wheels, Bodywork, Suspension, Lights & Electrics, Exhaust & Emissions and others. If you're inspecting a Mercedes Benz S Class before purchase, these are the areas to focus on — and if any have been flagged as advisories on a previous MOT, they're likely to become failures in the near future.
How failures change with mileage
The Mercedes Benz S Class's weak points shift as the car covers more miles. Understanding these patterns helps you know what to expect — and what to budget for — at each stage of ownership.
Under 60,000 miles
At this mileage, most failures are either design-related or caused by age rather than wear. Components like bushes and drop links may not have been replaced yet, and original-fit parts can deteriorate even on low-mileage cars that spend a lot of time sitting.
For the Mercedes Benz S Class specifically, the DVSA data shows the most common failures at this mileage are front or rear fog lamp with a multiple light so... (106x the average) and brake hoses perished or damaged (45x). wheel bearings worn (43x) and track rod ends worn (26x) also appear frequently.
60,000 to 100,000 miles
This is where routine wear items start to show up. Brake components, tyres, and exhaust parts have done serious work by this point. Cars that have been well serviced will show fewer of these failures — this mileage band is where good maintenance really separates the well-kept from the neglected.
For the Mercedes Benz S Class specifically, the DVSA data shows the most common failures at this mileage are front or rear fog lamp with a multiple light so... (77x the average) and emissions failure (33x). transmission shaft flexible coupling deteriorated (17x) and brake hoses perished or damaged (17x) also appear frequently.
Over 100,000 miles
High-mileage cars accumulate failures across multiple systems. The key question isn't whether things will need doing — they will — but whether the car has been maintained well enough to keep on top of them. Look for a consistent service history and recent MOT passes with minimal advisories.
For the Mercedes Benz S Class specifically, the DVSA data shows the most common failures at this mileage are suspension pin, bush or joint worn (24x the average) and transmission shaft flexible coupling deteriorated (20x). parking brake inefficient (12x) and any fracture or welding defect on a wheel (10x) also appear frequently.
The shift from front or rear fog lamp with a multiple light so... at lower mileages to suspension pin, bush or joint worn at higher mileages is typical — early failures tend to be design or factory-related, while high-mileage failures reflect accumulated mechanical wear. A car that's been well maintained will usually dodge the worst of both.
What to check before buying a Mercedes Benz S Class
Based on the MOT failure data and known issues above, here's what to prioritise when inspecting a Mercedes Benz S Class:
Wheels — check for any fracture or welding defect on a wheel. Bodywork — check for transmission shaft flexible coupling deteriorated. Suspension — check for suspension pin, bush or joint worn. Lights & Electrics — check for front or rear fog lamp with a multiple light so..., light unit fault.
Always check the car's full MOT history for patterns — recurring advisories often become failures within 12 months. And verify the service history to confirm maintenance has been kept up to schedule. Enter any reg into our free car check to see the complete picture.
Looking at a specific Mercedes Benz S Class?
Enter the reg to see its full MOT history, mileage records, write-off status, and finance checks.
Mercedes Benz S Class MOT FAQs
What are the most common MOT failures on a Mercedes Benz S Class?
Based on 172,840 DVSA MOT tests, the most common failure is any fracture or welding defect on a wheel — at 17x the national fleet average. Other frequent failures include transmission shaft flexible coupling deteriorated and suspension pin, bush or joint worn.
Is the Mercedes Benz S Class reliable based on MOT data?
The Mercedes Benz S Class has 18 categories where it fails more often than average. The main concern is any fracture or welding defect on a wheel. Always check a specific car's full history before buying.
What MOT failures should I expect at high mileage?
Above 100,000 miles, the Mercedes Benz S Class most commonly fails on suspension pin, bush or joint worn and transmission shaft flexible coupling deteriorated. Under 60,000 miles, the main issues are front or rear fog lamp with a multiple light so... and brake hoses perished or damaged.
How do I check a Mercedes Benz S Class's MOT history?
Enter the registration number into our free car check above. You'll see every MOT test result, advisories and failures, mileage readings, write-off status, and finance checks.
MOT failure data sourced from DVSA bulk test records via data.gov.uk. Ratios compare this model's failure rate against the national fleet average. Known issues sourced from manufacturer bulletins, specialist workshops, and verified owner reports.