TÜV (MOT) Test Report 2018: Suspension defects increase with age

Only the tip of the iceberg – this is how you recognise defective shock absorbers before it becomes critical

The new German TÜV (MOT) Test Report 2018 confirms that defects of the axle suspension and shock absorbers considerably accumulate with increasing vehicle age. On this subject, vehicles up to three years of age present 0.2 per cent defects, while vehicles up to five years of age already present 1 per cent and vehicles up to seven years of age 2.7 per cent. With vehicles up to nine years of age, the value finally reaches 4.2 per cent, to climb up to 5.5 per cent with vehicles up to eleven years of age.

But these numbers only represent the tip of the iceberg in our view: This is because in regular general inspections defects of the shock absorbers are only recognised if seen by the naked eye – this includes leaks, which are discernible by an oil film or by visually examined mechanical defects of the shock absorbers and protective tubes.

We therefore recommend having shock absorbers checked by a professional at least every 20,000 kilometres – during a service or the seasonal wheel change, for instance. Regular inspection – preferably in a workshop with shock absorber test bench – is highly important. This is because shock absorbers often have a “creeping” decrease in performance, i.e. the driver becomes used to it. And this can become very dangerous in risky situations – e.g. with emergency brakes, fast cornering or abrupt evasive manoeuvres. Here a vehicle with defective shock absorbers will swing off unexpectedly fast, as the tyres will lose their road adherence faster than usual. In addition, the braking distance increases by up to 20 per cent, the risk of aquaplaning rises and electronic assistance systems like ABS and ESP are well and truly “levered out”.

To prevent risk of safety, drivers should therefore actively request a shock absorber check at the workshop. This is particularly relevant if the mileage indicator reads many kilometres and the shock absorbers have not been replaced yet. By the same token, this is also true for workshops, as these can sensitise their customers, specifically in regard to this difficulty, during MOT appointments, inspections and tyre change.