2 questions

First off....how can you tell if you need new struts.Second what do they do?:bandit:

Give the car a good push down on the hood and then trunk lid. If the car bounces a few times before settling, then you probably need new shocks or struts. The car starts to ride like shit is another indication.

Basically a strut is a type of shock absorber.

thanks
:bandit:

Basically, a strut/shock (general/proper term is damper) keeps the car from bouncing all over the place when a tire hits a rough spot. The springs absorb the roughness, and then they expand - the dampers keep the expansion low.

The dampers also have a great deal to do with suspension movement, as they vary resistance to movement based upon movement velocity. The single most complex part of a suspension is the damper, there are many working designs and all have their relative pros and cons.

As far as what makes a strut a strut and not just a shock, it's all in the suspension design. Every modern car suspension has (almost exclusively) a hydrolic shock absorber, which dampens spring movment and has a hell of a lot to do with both ride quality and suspension performance (that second part does get complicated). Struts are used only in Macpherson strut suspensions (hence the name) and do the double job of dampers and the upper locating suspension link. So just understand that a strut is a shock which also acts as a stressed suspension member, which is why they are so beefy and heavy. For example, in a double wisbone system you have both upper and lower A arms which positively locate the wheels. The shock has NOTHING to do with locating the wheel in terms of suspension geometry, all they're asked to do is that complex primary job I mentioned earlier. A Machperson strut suspension setup tosses the upper control arm in favor of a strut which boths acts as the upper link and does the shock duties, which is certainly not an easy job.

yeah. I can tell that thier heavy cuz the cars curb weight is just under 3k. The car's suspension is fine it turns out except for squeking on the front right ball joint(I think).:bandit: