2006 BMW M5 5.0L Petrol · RX06 WVR

Corrosion on both rear brake pipes has been flagged in three consecutive MOTs (2024‑04‑20, 2025‑04‑26 and 2026‑04‑17), each time noted as “corroded, covered in grease or other material”. The repeat advisory indicates a persistent issue rather than an isolated incident, and the fact that the vehicle continues to pass suggests the corrosion has not yet progressed to a safety‑critical failure, but it remains the dominant mechanical concern. At 84,148 mi recorded for a 2006 model, the average annual mileage works out to roughly 4,200 mi, which is low for a car of this age. Such modest use often points to periods of limited running or storage, conditions that can accelerate surface rust on exposed components such as brake pipe fittings. The mileage record shows regular yearly MOTs with no large gaps, implying the car has been driven consistently enough to avoid the more severe degradation that can accompany long-term inactivity, but the low mileage does not eliminate age‑related wear on rubber seals, bushings and engine gaskets. Prospective buyers should give the rear brake system close attention. Visually inspect the rear brake pipe ends for any flaking rust, pitting or compromised protective coating, and verify that the grease covering is not masking active corrosion. During a road test, feel for any softening or sponginess in the rear brake pedal, uneven braking effort between left and right rear wheels, or a noticeable drop in pedal height after a few stops, all of which could signal pipe deterioration or fluid leakage. Listening for any hissing sounds when the brakes are applied can also reveal a developing leak. Because the MOT record is otherwise clean, the remainder of the car’s mechanical state is not documented, so a comprehensive pre‑purchase inspection is advisable. A specialist should check the condition of the rear brake lines, confirm the integrity of the brake fluid reservoir and hoses, and assess related components such as the rear calipers and mounting brackets for any signs of corrosion or fatigue. Budgeting for the replacement of the rear brake pipes, and possibly the associated fittings, would be prudent to eliminate the recurring advisory and ensure long‑term roadworthiness.