What goes wrong, what it costs, and what to check before you buy a used Triumph TR6.
The Triumph TR6 occupies a niche position on the UK market.
We track 5 known issues across the Triumph TR6 range, including 2 rated as safety-critical. Knowing which variants and configurations to approach with caution can save you from expensive surprises after purchase.
Found a Triumph TR6? Enter the reg to see which of our 5 known issues apply to that exact car, plus full MOT history and mileage checks.
TR6 (1968–1976) — Engine options included the 2.5L straight-six. Our database flags 5 known issues on this generation, 2 of which are rated as safety-critical. The most significant concern is Chassis rust (£1,000–£3,000 to address).
The TR6 uses a separate steel chassis with substantial side rails and cross-members that support the entire vehicle structure. The rear sections of the chassis rails are particularly vulnerable to corrosion from road salt, moisture, and debris accumulation. Rust typically develops from the inside out, making visual detection difficult until structural integrity is compromised. Failed MOT tests for chassis corrosion are common on surviving examples, with repair costs often exceeding the vehicle's value due to the extensive metalwork required.
Severe chassis corrosion creates a dangerous structural weakness that can lead to sudden failure of suspension mounting points or chassis fracture. The vehicle becomes unsafe to drive and will fail MOT testing. Professional chassis repair typically requires removal of the body shell and extensive welding or section replacement, with costs ranging from £3,000-£8,000 depending on the extent of corrosion.
Inspect the wheel arches, sills, jacking points and door bottoms carefully. Press gently on sills to check for soft spots. Look underneath for corrosion on structural components. Check the MOT history for corrosion-related advisories or failures.
The TR6 rear wheel bearings are large ball races housed in the rear hub carriers, with the differential drive flanges bolted to the hub assembly. These bearings experience higher loads than modern designs due to the solid rear axle configuration and wire wheel option creating additional stress concentrations. MOT data shows this model fails bearing tests at 57.6 times the national fleet average, indicating a fundamental design weakness or parts quality issue that has persisted across the classic car parts supply chain.
Failed wheel bearings create dangerous wheel wobble and can lead to complete wheel detachment or axle shaft failure. The bearing collapse can damage the hub carrier and differential output shaft, requiring extensive rear axle rebuild. Immediate professional inspection is required if bearing failure is suspected.
Listen for knocking, clunking or rattling over bumps during the test drive. Inspect the underside for corroded or cracked suspension components. Check the MOT history for suspension-related advisories, which often predict future failures.
The TR6 rear differential is a Salisbury unit with crown wheel and pinion gears that are prone to wear, particularly when oil levels drop or contamination occurs. The differential experiences high loads from the torquey straight-six engine and aggressive driving characteristic of sports cars. Noise typically develops gradually as gear tooth contact patterns deteriorate, but can progress rapidly to complete failure if oil starvation occurs.
Progressive differential wear leads to increasingly loud operation and eventual gear tooth failure. Complete differential failure results in loss of drive to the rear wheels and potential damage to the axle casing. Differential rebuild typically requires specialist work and costs £800-£1,500 depending on the extent of internal damage.
Listen for whining from the rear on deceleration and a clunk when changing direction — both signs of differential wear. Check for oil leaks around the differential housing. On performance cars, ask about limited-slip differential service history.
The TR6 front disc brake system uses single-piston Girling calipers that are vulnerable to piston seizure and slider pin corrosion. MOT data shows brake binding failures at 6.4 times the national fleet average, typically caused by corroded pistons sticking in their bores or seized slider mechanisms preventing proper pad retraction. The relatively simple brake design lacks the self-adjusting features of modern systems, making regular maintenance critical.
Binding brakes cause accelerated pad and disc wear, reduced braking efficiency, and potential brake fade under heavy use. Severely binding brakes can cause wheel lockup or unpredictable vehicle handling. Complete caliper rebuild or replacement is typically required, with costs varying significantly based on parts availability and caliper condition.
Check brake disc condition for lipping or scoring. Test braking at moderate speed for pulling to one side or vibration through the steering wheel. Review MOT advisories for brake-related items.
The TR6 straight-six engine is prone to oil leaks from multiple locations due to the age of rubber seals and gaskets combined with the thermal cycling experienced over decades of use. While rarely catastrophic, these leaks can pose environmental hazards and indicate broader engine seal deterioration.
Oil leaks rarely cause immediate mechanical failure but create environmental contamination and fire risk if oil contacts hot exhaust components. Persistent leaks indicate aging engine seals that may progress to more serious failures. The car may fail MOT testing if leaks are deemed excessive or environmentally hazardous.
Check the oil level before the engine is started. Ask the seller how often they top up the oil between services. After a test drive, check the level again and look behind the car for blue or grey exhaust smoke under acceleration.
For the full breakdown of all 5 tracked issues with repair costs, see the Triumph TR6 common problems page.
Based on 5k real DVSA MOT tests, the Triumph TR6 fails more often than average on several items. The biggest outlier is steering rack wear at 178x the fleet average, followed by excessive radial movement between the top of th... (110x).
When viewing a specific car, check its MOT history for recurring advisories in these categories. See the full Triumph TR6 MOT failure breakdown for data at every mileage point.
Routine servicing (oil and filter change every 6k miles) typically costs £80–£120 at an independent garage.
See the full Triumph TR6 service schedule for every interval and cost breakdown.
The Triumph TR6 has some well-documented weak points, including 2 safety-critical issues that demand careful checking. The right example, properly maintained, can still be a sound purchase — but cutting corners on the pre-purchase inspection is not advisable.
Before committing, check the car's full MOT history, verify the service record is complete, and if possible arrange a specialist inspection. Enter any registration into our free report to see the complete picture.
Get Car Wise maintains a database of known mechanical issues for every popular car on UK roads, tracking the faults that owners, specialists and DVSA data reveal.
When you run a report on a specific Triumph TR6, we cross-reference the exact variant, engine and age against our database of 5 known issues. Combined with full MOT history analysis, mileage verification and DVLA data, you get a complete picture before viewing.
Enter the registration for MOT history, mileage verification, known faults for that exact variant, and a Get Car Wise Score.
This guide was compiled from independent expert reviews, DVSA MOT data, specialist workshops and our own database of 5 known Triumph TR6 issues. We are not affiliated with any source listed.