Airmatic drops front sometimes overnight or few days

[PeterQ]

My 1999 S430L Airmatic drops at the front sometimes, overnight or after a few days of non-use. I start it up, get the "Too low!" message and then the car pumps up and all is well. As a former 6.9 owner I'm sort of used to this behaviour (without the alarmist message on the dash), but I don't know if I should be worried in this case. I don't seem to have any leaks at the top of the strut.
So, should I worry/panic yet?

[John Green]

Hi Peter, whilst what you describe is not ideal, so long as it comes up quickly I would not panic too much. Many $$$$$$$ in parts will only allow you drive away a few seconds quicker.

[PeterQ]

Well I took a look at a few things last weekend, nothing obvious. But, the infamous relay is not the "bad" Siemens nor the "good" Hella, but a Tyco. Hella replacement coming, just in case. Tops of struts are very clean and appear intact. I found a bill for "replace right front shock - supplied" from December 14, so this weekend I'll start spraying joints in that area with soapy water looking for bubbles. Could just be a joint not quite sealing. This is like my old 6.9, just not so oily. On the other hand, the oil made it easier to find the leaks.

[PeterQ]

So I replaced the Tyco relay with the preferred Hella, not expecting it to make any real difference, just a peace of mind thing. But now it's not dropping so much - still does it but not enough to get the "Too low" display.
Please explain.