What do struts on a car do? how often do the need to be replaced?

Here's everything you ever wanted to know about shocks and struts.

http://ricksfreeautorepairadvice.com/shocks-and-st...

Struts are the assemblies which do the actual suspending of the body from the chassis on vehicles designed and equipped with them. Without them there is no driving of the vehicle because it would be physically disabled.

They are a shock absorber that forms the upper pivot point for turning, so they are an active part of the alignment geometry. They normally last 60-80K miles depending on how brutal the roads were. You can tell their condition by inspecting them for leaks and the good old bumper bounce test for rebound.

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