2009 Mercedes B-Class 2.0L Diesel · KEN 50G

A fractured rear coil spring and a recurring brake pipe corrosion advisory define the mechanical story of this 2009 Mercedes B-Class, with the most recent test on 3 December 2025 returning a pass only after a failed re-presentation a fortnight earlier on 19 November 2025. The 2025 failure was driven primarily by the nearside rear coil spring, classified as a Major defect, alongside advisories for a worn offside front tyre, a cut on the same tyre, and again the nearside rear brake pipe corrosion. Prior to this, the 2024 and 2022 tests passed without any recorded defects, and a 2023 test passed with only an advisory for inner face wear on both front brake discs, so the trajectory has moved from a relatively clean record to a cluster of chassis and braking concerns concentrated in late 2025. A prospective buyer should treat the November 2025 failure not as an isolated event but as a warning that suspension and underbody components on this seventeen year old car are now entering a phase of active deterioration. Recorded mileage of 65,996 miles across seventeen years equates to an annual accumulation of roughly 3,882 miles, which is substantially below the average for a vehicle of this age. MOT tests appear at regular intervals between 2022 and 2025, suggesting the car has remained in active use rather than being laid up for prolonged periods, although the low annual mileage still means many components will have aged through time rather than cycles of wear. Brake discs, brake pipes, rubber suspension bushes, coil springs, and flexible hydraulic hoses are all particularly vulnerable to this kind of slow, time-driven degradation, which is consistent with the rear coil spring fracture and the recurring brake pipe corrosion advisory. The relatively low odometer reading should not therefore be interpreted as evidence of conserved mechanical condition, and components that would normally be replaced at higher mileages may still require attention purely on the basis of age. Focusing on the specific items flagged in the MOT record, the nearside rear coil spring failure is the most pressing concern and warrants immediate verification. On a test drive, listen for clonking or knocking noises from the rear suspension over speed humps, uneven bumps, and rough tarmac, and check visually that the vehicle sits level at the rear when parked on flat ground, as a fractured spring will often cause that corner to sit lower than the opposite side. The nearside rear brake pipe corrosion advisory has now appeared across two consecutive tests in late 2025, which suggests surface corrosion is established on that section of pipework and may have been masked by grease. Brake lines on a vehicle of this age and exposure are at risk of progressing to perforation, so the underside should be inspected closely for any flaking, pitting, or active rust weeping around the rear brake line run, and the brake pedal should feel firm and progressive without any sponginess or excessive travel on the road. The 2023 advisory regarding inner face wear on both front brake discs should also be revisited, as disc wear of that nature tends to progress, and any pulsing through the brake pedal or steering wheel vibration under braking would indicate the discs have now reached a serviceable limit. The tyre related advisories from the failed November 2025 test, covering both excessive edge wear and a sidewall cut on the offside front, point towards either alignment irregularities or simply aged rubber. On inspection, confirm that the tyres are of matching brand, size, and tread depth across both front corners, and check for uneven shoulder wear which can indicate worn suspension bushes or worn front strut top mounts rather than just alignment. With the vehicle now approaching eighteen years of age, attention should also be directed to items that the MOT process does not fully cover but are strongly implied by the recorded defects, particularly the condition of the front and rear anti roll bar bushes, drop links, wishbone arms, and subframe mounting points, all of which can contribute to the knocking noises and uneven tyre wear already observed. A thorough pre-purchase inspection on a ramp, combined with a careful test drive over varied road surfaces paying particular attention to rear suspension noise, brake pedal feel, and steering precision, is strongly advisable before committing to purchase.