Self levelling shock absorber
Leaking levelling shock absorbers can usually be recognised by oil stains in the area of the rear wheels and a sinking rear end when parking.
The level control system essentially consists of the suspension cylinders (also known as level shock absorbers), the suspension accumulators (also known as pressure accumulators or pressure bombs), the height control valve, and the pump. The pump is the least conspicuous component in terms of possible defects. The height control valves also generally work reliably. In rare cases, they can leak, which can occur both externally (visible oil loss) and internally (not visible but possible malfunction in height control). The dampers usually leak. In most cases, however, these leaks are consequential faults caused by defective suspension accumulators.
In addition, the suspension often feels hard and uncomfortable. The rear end is often too high and, in extreme cases, can really bounce, which can be torture for both man and material. The cause of this is usually not the damper cylinders themselves, but the suspension accumulators.
Leaking suspension cylinders can almost always be repaired. However, as they must always be considered as a functional unit with the suspension accumulators, the condition of these accumulator spheres must always be clarified when repairing the shock absorbers. It is recommended to replace the suspension accumulators, or, if possible, regenerate them at the same time. However, they must at least be checked for residual pressure.