The Lexus Strut is part of the front suspension system on many vehicles of this brand of cars. There are many that refer to it as the Macpherson strut. This is the suspension component on your Lexus that has replaced the need for a shock absorber and coil spring.
Just like the shock absorber, the strut is a hydraulic system that in time will wear out and no longer be able to absorb the vertical movement of the vehicle when it encounters an obstacle on the road's surface. When this happens on your Lexus, it has to be replaced so a smooth ride down the road can occur for not only the passengers of your vehicle but also the other components that make up your car.
If you suspect the Lexus struts are failing, a simple test can be performed by the owner of the vehicle that will provide a clear answer to this question. This is the bounce test. The same test can be used if shock absorbers are on a vehicle.
The bounce test involves the depression of one corner of the vehicle and then it being released. When the body is released it will move in a vertical fashion. As a point of reference for the Lexus owner a new strut will allow the body to move up then back to a resting position. If the body moves up and down more than once then the suspension system is worn and the replacement of parts should occur before too long of a period expires.
Properly working struts on your vehicle not only provide for a smooth ride but prevent any excessive vibration from occurring on your car so the other components do not prematurely wear.