Triumph Stag Auto MOT Failures
An analysis of 3,646 real DVSA MOT tests on the Triumph Stag Auto — what fails, how often, and how that compares to every other car on UK roads.
Where the Triumph Stag Auto fails its MOT
The single biggest MOT failure point on the Triumph Stag Auto is wheel bearings worn — this model is 69 times more likely to fail on this item than the average car on UK roads. That makes it a major concern for anyone buying or owning this model. Across 3,646 MOT tests, 16.55% of all Triumph Stag Auto tests recorded this as a failure.
Suspension failures typically mean worn bushes, drop links, or dampers. These affect handling and tyre wear. Budget £150–£400 per corner at an independent garage for full suspension overhaul.
Other notable weak points include fluid leak (65x the fleet average), abs fault (37x the fleet average), significant brake effort recorded with no brake... (18x the fleet average), and windscreen washers not working or not providing... (7.5x the fleet average). These ratios compare the Triumph Stag Auto'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 4 categories: Suspension, Exhaust & Emissions, Brakes, Wipers & Windscreen. If you're inspecting a Triumph Stag Auto 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 Triumph Stag Auto'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 Triumph Stag Auto specifically, the DVSA data shows the most common failures at this mileage are fluid leak (65x the average) and wheel bearings worn (53x). abs fault (37x) and significant brake effort recorded with no brake... (18x) 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 Triumph Stag Auto specifically, the DVSA data shows the most common failures at this mileage are wheel bearings worn (22x the average) and fluid leak (14x). windscreen washers not working or not providing... (7.5x) and abs fault (5.7x) also appear frequently.
The shift from fluid leak at lower mileages to wheel bearings 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 Triumph Stag Auto
Based on the MOT failure data and known issues above, here's what to prioritise when inspecting a Triumph Stag Auto:
Suspension — check for wheel bearings worn, abs fault. Exhaust & Emissions — check for fluid leak. Brakes — check for significant brake effort recorded with no brake....
Always check the car's full MOT history for patterns — recurring advisories often become failures within 12 months. Enter any reg into our free car check to see the complete picture.
Looking at a specific Triumph Stag Auto?
Enter the reg to see its full MOT history, mileage records, write-off status, and finance checks.
Triumph Stag Auto MOT FAQs
What are the most common MOT failures on a Triumph Stag Auto?
Based on 3,646 DVSA MOT tests, the most common failure is wheel bearings worn — at 69x the national fleet average. Other frequent failures include fluid leak and abs fault.
Is the Triumph Stag Auto reliable based on MOT data?
The Triumph Stag Auto has 5 categories where it fails more often than average. The main concern is wheel bearings worn. Always check a specific car's full history before buying.
What MOT failures should I expect at high mileage?
The most common high-mileage failures include wheel bearings worn, fluid leak, abs fault.
How do I check a Triumph Stag Auto'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.