Odd: Front shocks leak when battery connected?

[91 LSC SE]

Could it be the park drop, not fully closing the values?

In short, they do not seem to loose air with the battery disconnected and with battery connected, the shocks lower in two days with the car not started or driven.

Symptoms and details below.

I have owned my M8 for almost 3 years now and the front would lower every few days to a week, if I left the switch off.
I thought as they both lowered at the same rate, it was the small round rubber seals and had plans to replace them.

I recently replaced LCA's & UCA's and Strut Rod bushings, so she has been sitting for a while.
When I turned on the Air suspension from my switch inside the interior, (also installed an ASHAM 8), the shocks lowered in two days and thought it was due to the recent cold 17 fahrenheit. Before that it has been hovering above 40 fahrenheit, Thankfully.

I raised it again and this time disconnected the battery and it was a week and a half and they didn't lower. I connected the battery and they lowered in two days. Has anyone else had noticed this?

 

[unity]

The struts leak at the folds in rubber. Since there is a "window" for park height, the cracks are never in the exact same spot in the fold when parked. So at first, the lowering may be random. Then as the crack gets worse, the lowering is more consistent.

In theory, they should never leak down. And I bet when you pulled the battery the car was still "high" and the cracks in the folds sealed. Not to mention you were not driving it. If you want to test for leaks, just drive with the switch off - probably want to turn the switch off at park height since that is were the leaks will be the worst.

As for lowering at same rate, they probably dont. But if one leaks, the whole front comes down.

 

[91 LSC SE]

I heard they can also leak at the small round o-ring seals. It seems strange that the car sat at the same height for almost two weeks and then dropped 5+ inches in two days, with the only change being the battery being connected. When I raised the suspension with the ASHAM8 just before that time it dropped in two days and the battery was connected and not be driven (same variables). The only other difference was it was 40 degrees and then went colder to 17.

 

[unity]

They o-rings can, but not usually unless messed with. And if it was them, it would leak down all the time.

And not strange at all. Battery connected, the car may have adjusted height. It will do so for up to 20 minutes (I think) after running. Or in your case, adding power again.

Simple fact is the bags are leaking at the folds.

 

[91 LSC SE]

They o-rings can, but not usually unless messed with. And if it was them, it would leak down all the time.

And not strange at all. Battery connected, the car may have adjusted height. It will do so for up to 20 minutes (I think) after running. Or in your case, adding power again.

Simple fact is the bags are leaking at the folds.

They have leaked slowly all the time (if sitting), since I bought the car almost 3 years ago and haven't gotten worse. Last week was the first time they didn't, after almost two weeks of sitting. Usually noticeable within 2 days of sitting and the front lowers about 3 to 5 inches with 5 days of sitting.

I used the ASHAM8 to raise the M8 higher than normal and let it settle, before disconnecting the battery, as I knew she would be sitting for over a week. A week and a half, she was the same height. Then when I connected the battery (didn't change the ASHAM8 module) she dropped about 5 inches in two days.

My M7 has almost double the miles and I lowered that when we first got in and she never drops when sitting. I know they are different style air shocks, but find it hard to believe the M8's would last only half as long.

I guess the only way to be sure is to raise the front again and disconnect the battery and leave her sit for a couple of weeks. Or turn of the system and drive her as you suggested.