FelixBabakuntos

I recently got two front air struts from a junked 2005 Ultra Luxury. How do I evaluate them prior to installation to see if they are fully functional? Neither had large oil leaks, though both had a little bit of oil come out of the air line when I first compressed the suspension. One of the struts compresses and decompresses slowly, while the other one does not compress at all when pushing on it with my body weight.

I saw this YouTube video showing an air strut test but it does not say if the strut was behaving properly and if not, why not.


Any insight would be appreciated.

BigBoomer

That looks like it's behaving normally. If you have one that you cannot compress at all, check that the air line isn't blocked.
Otherwise it may be seized so may require more weight to free it up.
Once under air-pressure the strut will behave like a normal coil-over.

Air-suspension is simple to understand.
All it does is replace the spring with an air-bag that behaves like a spring when under pressure, and often they have a weaker coil spring in addition to the air-bag.
Higher pressure = higher preload and higher ride height.
Where it gets complicated is in the computers that control it, not in the strut itself.
The LS430 air-strut has computer controlled preload/ride-height and damping.