Does it have strutts or shocks - 1998 Cadillac Catera

Look on the inside of the tires, the struts are the coil springs with the shock absorber inside. You should have two on the front and two on the back. You should have someone put them on that knows what they are doing. It can be dangerous and someone could get hurt if you aren't careful.

You can test them by pushing down at each corner of the vehicle, like trying to bounce it.
When you let it up do so quickly and it should spring back and stay still.
If it bounces once or twice then the shocks need looking at or testing.

No, you don't need to compress the spring, a jack under the axle will allow easier lining up of the bottom bolt, without extending the shock absorber.

If the air ride is working, then it is one of the shock sensors is unpluged or the airpump is fixing to go out, I would check all 4 shocks or strutts and check the plugins and if that dont help i would diable the airride and change it over to spring over strutt style. You will have to have a shop to this cause it is a big job, but in the long run your ride is better and you dont have to worry about it anymore.

First you will need to jack up the car to relieve the tension on shock, then remove the two bolts one located at bottom of strutt and the other will be at the top. Replace the new strutt by lowering the car down till the strutt slides on to the original locations.

Shocks in the back and struts in the front. Don't forget the strut mounts bushings when replacing the front struts.
Thank you for using Fixya and good luck

Shocks / strutts no good.

There is obviously other suspension or exhaust bracket problem that is looose. Check all the bushings in the front end, your steering linkages, recheck the strut bolts, check the entire exhaust system to see if it rattles and look for loose brackets or things maybe hanging down on the car. Also look at motor mounts to see if one is broken. Hope this helps you, Rick

You may have to visit the ealer on these. I have checked as well , and everything I find available says not for the adjustable suspension models. SOmeone at the dealer may be able to give you an aftermarket suggestion that will work as well.

also, check here, you may find this information useful!
http://www.automotiveforums.com/vbulletin/forumdisplay.php?f=105

your car has strutts not shocks front and back i had to replace all four.