2018 Mercedes-Benz C 1.9L Diesel · RF68 WNU

The vehicle’s roadworthiness trend has deteriorated sharply over the past year, with the most recent MOT in May 2026 revealing a critical welding defect on the nearside front road wheel—an immediate structural risk that required a fail despite the clean 2026 pass on the same day. Prior to that, the April 2025 tests exposed a pattern of unresolved issues: distorted and repaired front road wheels, worn and pitted rear brake discs, thinning brake pads, and fluctuating rear brake performance, alongside cosmetic but persistent defects like a damaged front bumper and defective headlamp lens. The active brake assist warning light and undertray obstruction further indicate neglect in routine checks, suggesting the vehicle has not been consistently maintained to manufacturer standards. While the October 2023 MOT showed no defects, the subsequent 18-month gap between tests—during which mileage rose by 21,887 miles—points to either delayed servicing or a lack of proactive upkeep. The mileage accumulation of roughly 10,926 miles per year aligns with typical usage for an eight-year-old vehicle, though the rapid 21,887-mile jump between October 2023 and April 2025 (a span of 18 months) may have accelerated wear on high-stress components. The near-identical mileage figures in the May 2026 fails (87,402 and 87,404 miles) suggest the vehicle was driven minimally between tests, likely to address the welding defect. The absence of MOT records between October 2023 and April 2025 is unusual for a vehicle of this age and value, raising questions about whether it was kept off the road or simply not tested—both scenarios imply deferred maintenance. A prospective buyer should prioritise an independent inspection of the front suspension, particularly the road wheels, given the repeated distortions and repairs flagged in 2025. The rear brake system demands close scrutiny: pitted discs, thinning pads, and fluctuating brake performance indicate uneven wear or potential caliper binding, which could lead to premature failure. Structural integrity is another concern, with the welding defect on the front road wheel and undertray obstruction hinting at possible corrosion or prior damage not fully addressed. The active brake assist warning light should be diagnosed, as it may reflect deeper issues with brake system electronics or sensor functionality. Cosmetic damage, while not safety-critical, could mask underlying rust or impact resale value, so a thorough underbody and wheel arch inspection is advisable.