2017 Mercedes-Benz S-Class 4.7L Petrol · GN51 AAN

The latest MOT test conducted on 21 February 2026 resulted in a pass with no defects recorded. However, the maintenance trend shows a concerning recent lapse in vehicle upkeep, as the vehicle failed a test just three days prior to this pass. The failure was categorized as dangerous due to the nearside front tyre tread depth falling below the legal 1.6mm limit and the rear brake pads being worn below 1.5mm. While the immediate rectification of these items has allowed for a clean pass, the sudden transition from several years of clean MOT records to a dangerous failure suggests that routine inspections of consumables may have been neglected. The recorded mileage of 33,848 miles is exceptionally low for a nine-year-old vehicle, representing an annual average of approximately 3,761 miles. While this indicates minimal wear on the engine, transmission, and major drivetrain components, such low usage often implies the vehicle has spent significant periods stationary. In premium vehicles like the S-Class, infrequent driving can lead to specific mechanical issues such as the degradation of rubber seals, battery depletion, and the buildup of corrosion on brake discs and calipers due to a lack of regular heat cycles and friction. Prospective buyers should pay close attention to the braking system and wheel alignment. The recent advisories regarding pitted and scored rear brake discs, combined with the failure of the rear pads, indicate that the rear braking assembly is nearing the end of its service life or has suffered from moisture-induced corrosion. During a test drive, listen for any metallic grinding from the rear wheels and feel for any shudder or pulsation through the brake pedal, which would suggest uneven disc surfaces. Furthermore, the advisories for uneven tyre wear on both the nearside and offside rear tyres suggest that the rear suspension geometry or wheel alignment may be out of specification. Inspect the tyres for any irregular wear patterns that could point to worn suspension bushes or faulty camber settings. Given the low annual mileage, a physical inspection of age-related degradation is essential. Examine the tyre sidewalls for any signs of perishing or cracking, as tyres can become unsafe due to age even if the tread remains deep. It is also vital to verify the service history to ensure that all fluids, including engine oil, coolant, and brake fluid, have been changed according to the manufacturer's time-based intervals rather than solely on mileage. Additionally, check for any signs of fluid weeping from the engine bay or underside, as stationary vehicles are prone to seal shrinkage and subsequent leaks. Finally, ensure the 12V battery has been tested, as low-use vehicles are highly susceptible to voltage drops and capacity loss.