I think that you're interchanging control of damping with control of ride height:
The ride height is controlled as a primary function of the displacement of the lower arm (not the strut), for it is that measurement which is used by the control unit to determine how much pressure should be applied to the air spring in order to dynamically vary ride height.
The damping is varied, by the control unit, in response not to displacement, but instead to a second order function of it (i.e. double differential wrt time). (Except in an Arnott strut where we both agree that it cannot be done). The absolute position of the strut is ignored.

 

That wasn’t for you DG 😂
He said something about buying it so I was just saying no need when we have his back in here.

 

Thanks very much Dark Green for sharing.

 

Hello folks,

I hope that you are all safe and well in these strange times.

I bought the Areosus front suspension struts and my local service agent installed last Friday without issue. I provided him with the service manual and a YouTube clip, both of which were very helpful and I am grateful to you all on this forum for the help and advice 🙏.

I drove the car for approx 120 miles and parked it up on Saturday evening. 36 hrs later I notice that the suspension has dropped again with the tyres tucked under the wheel arch.

​​​​​​I had hoped that the replacement of the front struts would have fixed this problem but it doesn't seem to have worked. Similarly to before the new struts were installed, the drop appears to be slightly more pronounced on the front right.

I started up the car this evening, approx 48 hrs after last use and there were no warning lights or notifications but I wonder if I had let the car sit for another day or two, would there be a different outcome and whether this new sag is an indication of a true problem.

Any thoughts?

Kind regards,

JFIRL

 

A note for US buyers considering Aerosus struts. You will be required to pay a 25% duty on their struts because they are made in China.

 

This has been an enlightening thread. Thanks for all the input. I’m facing perhaps a similar issue to the OP but, my 05 GT takes about a week of “sitting” before it’s down on the wheel arches but that would imply a very slow “leak”?

Weirdly however, my GT seems to go down almost identically at all four corners. I haven’t measured, but I’ve had the neighbours ask if I’ve had the car lowered! That’s how even it goes down?

Is this possibly the same issue or is it something else? The suspension control unit in the boot perhaps? No idea, just guessing here from what I’ve read on these forums so far.

Btw, when I start it up it all rises back up to norm. I get the initial (too low) warning on the dash but that clears within a few moment as the car rises back up to its normal height.

Any info would be much appreciated.

 

As the car, as you said, seems to drop identically on all 4 corners, I wouldn't rule out the possible effect that the temperature has on a relatively small pressurised chamber as is the case of the struts fitted to these cars. When you stop the car after a long drive in the heat the pressurised air inside the struts is very hot and the control module has been actuacting accordingly to maintain the correct programmed height. If you leave the car standing for a few hours as the temperature drops so does the pressure inside the struts chambers and in the morning after a cold night you may notice a appreciable drop on all 4 corners because there no way the CM can adjust the pressure to compensate for the height drop until you start up the car.
This I have experienced many times happening in my car and there is no leak anywhere. It sometimes drops more than 1 cm overnight and if I let it parked in the garage for a further 1 month I will get 0 cms drop after that, which is a proof of no leak.
So before you jump on changing parts verify whether or not this may also be your case.