2017 Mercedes-Benz C 2.1L Diesel · MK17 ACV

The September 2025 test at 90,458 miles returned a pass with only a single advisory for a severely deteriorated nearside front lower suspension arm ball joint dust cover. This marks a clear improvement from the October 2023 failure where rear brake pads measured below 1.5 millimetres, both rear tyres fell below the legal tread limit and service brake efficiency fell short of requirements. The July 2023 failure on both front lower ball joints for excessive wear was rectified before the October retest, and no further suspension or brake defects have appeared since. Mileage accrual averaged roughly 10,000 miles per year until 2022 when the odometer read 66,111 miles at the June test. A sharp increase followed, covering 19,000 miles in the fourteen months to October 2023 at 85,380 miles. Since then annual distance has dropped to around 2,000 miles, with the 2024 test recording 88,316 miles and the latest 90,458 miles. Test intervals have remained broadly annual, with no unexplained gaps in the record. A buyer should focus inspection on the front suspension lower arms. Both ball joints were replaced after the July 2023 failure, yet the nearside dust cover had already deteriorated severely by September 2025, suggesting either a substandard replacement part or inadequate grease retention. Check for play in the joints and any sign of grease leakage. Rear brake discs and pads warrant close measurement given the 2023 wear-to-metal condition; verify current pad thickness and disc lip depth. The recurring rear tyre edge wear in 2022 and 2023, plus the 2021 offside front tyre structural failure, points to possible alignment or geometry issues — inspect tread patterns across all four corners and confirm the steering geometry has been checked recently. The history reveals a pattern of reactive maintenance: consumables such as tyres and brake pads were repeatedly run to or beyond legal limits before replacement, while major safety items like ball joints were only addressed once they caused a test failure. The recent low mileage and clean tests suggest the current keeper may be maintaining the car more diligently, but the suspension dust cover advisory indicates the 2023 repair may not have been completed to a lasting standard.