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Triumph Tr6 Problems & Known Issues

The most common Triumph Tr6 problems ranked by severity — what to watch for, what it costs to fix, and what happens if you ignore it.

Generations

TR6 — TR6
1968–1976
2.5L straight-six

Top issues to watch for

The most serious Triumph Tr6 problems ranked by severity. We track 5 known issues — here are the ones you need to know about first.

Dangerous
Chassis rust (TR6)
TR61968–1976
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.
What happens if ignoredSevere 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.
Independent garage
£1,000–£3,000
Specialist
£2,000–£5,000
Main dealer
£3,000–£8,000
Parts only
£200–£800
Dangerous
Wheel bearing failure (TR6)
TR61968–197620k–120k miles
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.
What happens if ignoredFailed 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.
Independent garage
£200–£400
Specialist
£300–£600
Main dealer
£400–£800
Parts only
£80–£150
Major
Differential noise (TR6)
TR61968–1976
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.
What happens if ignoredProgressive 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.
Independent garage
£400–£800
Specialist
£600–£1,000
Main dealer
£800–£1,500
Parts only
£200–£500
Major
Brake binding (TR6)
TR61968–19760k–100k miles
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.
What happens if ignoredBinding 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.
Independent garage
£150–£300
Specialist
£200–£400
Main dealer
£300–£600
Parts only
£80–£200

1 more known issues tracked

Including wear items, electrical niggles, and generation-specific problems. Check a specific car to see which issues apply to its age and mileage.

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MOT failure hotspots

Based on DVSA MOT test data. These are the items where the Triumph Tr6 fails at a significantly higher rate than the average car.

Steering rack wear
Steering · 20-40k miles
MOT failure rate: 178x the fleet average
Sample: 348 tests
Excessive radial movement between the top of th...
Steering · 0-20k miles
MOT failure rate: 110x the fleet average
Sample: 528 tests
Wheel bearings worn
Suspension · 20-40k miles
MOT failure rate: 58x the fleet average
Sample: 842 tests
Fluid leak
Exhaust & Emissions · 0-20k miles
MOT failure rate: 28x the fleet average
Sample: 1,317 tests
Electrical wiring fault
Lights & Electrics · 0-20k miles
MOT failure rate: 20x the fleet average
Sample: 483 tests
Suspension joint dust cover severely deteriorated
Suspension · 0-20k miles
MOT failure rate: 19x the fleet average
Sample: 541 tests

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Related

Triumph Tr6 reliability FAQs

What are the most common problems with the Triumph Tr6?

The Triumph Tr6 has 5 known issues across 3 severity levels. The most serious are: Chassis rust (TR6), Wheel bearing failure (TR6).

Is the Triumph Tr6 reliable?

The Triumph Tr6 has 2 dangerous and 2 major known issues. Most can be avoided with a thorough pre-purchase check and full service history.

How much does it cost to fix Triumph Tr6 problems?

Repair costs range widely. The most significant issue (Chassis rust (TR6)) costs £1,000–£3,000 at an independent garage. Minor issues can be under £200. Always get a full inspection before buying.