First Line: Straight from the Top

First Line talks top strut mount failure: the why, the how, and the when.

Top strut mounts and bearings have evolved from ‘Generation Ø’, featuring a simple steel bearing in a steel beading, to ‘Generation 2.5’, which uses a steel bearing with integral upper spring and shock absorber support, made from sophisticated, premium quality plastic composites. Despite this transformation, top strut mounts and bearings are still susceptible to failure.


Common causes of failure include corrosion from water, sand and salt on the roads, fractures from poor road surfaces or accident/collision damage, and brinelling from micro-vibrations and incorrect hardening. Freezing conditions combined with water penetration cause additional problems by damaging the bearings as well.

Some failures are linked to poor design, forcing OE manufacturers to re-design and upgrade them. On some vehicles however, it can be the case that the top strut mount fails prematurely, particularly with a number of Fiat applications including the Fiorino/Qubo (and their Citroën Nemo, Peugeot Bipper/ Tepee cousins), Doblo, Grande Punto and Ducato.


Spotting the failure should be relatively straightforward. Failure can result in increased noise – clunking, knocking, grinding or creaking – particularly at low speeds, when moving the steering from lock to lock on poor road surfaces, as well as increased torque on the steering wheel. Note that a faulty top strut mount or bearing can affect the other suspension components and will increase the chance of their subsequent failure.


Worn suspension components can increase braking distance by 15% and vibration by as much as 25%, making the vehicle much less responsive. Therefore, it’s advisable to replace them every 50,000 miles, or whenever the shock absorber or coil spring is changed.

As with any suspension work, these components should be replaced in pairs. This is a prudent policy not only because it’s more economical for the owner, but it also avoids inequality in the vehicle’s steering geometry.


For peace of mind, First Line top strut mounts, bearings, and top strut mount kits are made from premium quality components to OE specifications and undergo stringent examination, as well as detailed application referencing, by the company’s highly qualified product team.

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Published on: March 22, 2020

Filled Under: Technical Articles

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