Struts are one of the active components of the suspension system that absorb the irregularities on roads to ensure a smooth driving experience for the passengers. While this is also the basic purpose of the shock absorbers, the struts form a structural part of the suspension system. The struts stabilize the suspension system while adding increased tension and support to it, along with other suspension components. Struts are connected to the steering rack, replacing the upper control arm. Internally, the design and function of the strut is similar to that of a shock absorber. MacPherson struts are the most common types of struts used in automobiles. Most MacPherson struts have a coil spring wound around them like the coilover shock absorbers.
The strut usually has an upper strut mount connected to its one end while a bump stop is attached to the lower end. The bump stop prevents metal-to-metal contact of the strut with the other suspension components, while also adding to the shock absorbing ability of the strut, when it reaches its limit.
In the case there is a defect or irregularity in the bump stop, strut mount or the shock section, they can usually be replaced individually to fix the problem. After installing the new part, all these three components need to be aligned with one another to ensure their proper functioning. In some strut designs, the strut mount, bump stop and the strut come together as a single unit. These types of struts are called loaded struts. In case of the failure of a loaded strut, the entire assembly needs to be replaced. While replacing these struts, care should be taken since the coil spring needs to be compressed. Apart from loaded struts, there is also another category of struts that come with replaceable cartridges. These struts can be replaced easily without having to remove the strut from the vehicle. During the replacement of any kind of strut, the wheel alignment also needs to be checked.
If you remove a shock absorber, the vehicle can still run with the rest of the suspension system, but with severe vibration and minimal control. However, in case of struts, since they form the structural part of the suspension, the vehicle cannot run if they are removed.