Unlike shocks, the BMW 528i struts have a lot of functions that make it an integral suspension part of the car. It supports the vehicle's weight with compression and decompression motions. Unfortunately, this part is not forever to stay. Its dampening capabilities reduce over time until it is time to replace it. Problems with the struts start with swaying of the car, decreased suspension strength, and longer braking distance. To be sure that your struts are not working well, following are some information you might find useful.
This symptom is very easy to tell. Obviously, bad struts will have less power to compress or decompress. With this, since it supports the weight of your car, it will not be able decompress and raise the vehicle to its normal height. As a result, a part of the car may seem lower compared to the other sides. This is coupled by a less stable car body position.
If worn struts are subject to severely uneven terrain, they will tend to shake uncontrollably. This is because a bad strut will have less supporting capacities and having it run on bumpy roads will expose it to more abuse from the vehicle's weight which it could no longer support. If you notice abnormal shakes in a particular side of your BMW 528i, you might want to check the strut on the wheel of that side.
Most struts work with a hydraulic fluid inside the body to produce pressure in compressing and decompressing. However, since the struts always work hard, they are very much prone to damage and break. Once there is break, the hydraulic fluid inside the body will leak out, lessening the pressure the strut produces. To check for this problem, look for oil leaks at the top or bottom part of the struts.
Bad struts have reduced tension and pressure. This makes its internal parts almost hollow. As a result, the inner part assembly will tend to collide with the outer strut assembly, making a rattling sound when driving your vehicle on the road. To be certain if the sounds are coming from one of your BMW 528i struts, give your car a drive over bumps and rough roads. Pay close attention to the sound and determine which strut is making it.