SW20S

So I have noticed lately that the front suspension looks like it settles out a lot overnight. I drove the car yesterday, and got in it just now and here's what the front wheel looked like:



I measured before I left from the floor and the fender lip was 27 1/4 inches from the ground. Went out and ran some errands and measured after I parked and I'm at 28 3/4 right after shutdown. So, 1.5 inch drop in 24 hours strikes me as a lot, no? I measured the rears just now and they too are at 28 3/4. I will let it sit overnight and measure in the morning. The rear did not look low when I got into it this afternoon.

Thoughts?

carlosinseattle

Sorry to hear ab\out this. You just got your car back from the shop, so the last thing you want to deal with is another problem. Was it even on both sides, or was the left front lower than the right front?

SW20S

Seriously! Even on both sides.

S_W222

I posted about this in the past, and here is a copy of my notes/response at that time:

I've been taking measurements (distance between the lower edge of the rim to the fender) over past 2 days:
Baseline: 27.25 inches (2 days "48 hours" measurement )
Distance between the lower edge of the rim to the fender):

• Baseline: 27.25 inches (day 1 morning)
• after 12 hours: 26.75 inches (day 1 night )
• after 24 hours: 26.75 inches (day 2 morning)
• after 36 hours: 26.75 inches (day 2 night).
• After 48 hours: 26.75 inches (day 3 morning)

Experiment is done. This confirms the air contraction theory for the W222 AIRMATIC system, during first 12 hrs only before it stabilizes, with around 0.5 inches due to air contraction. My observation is that this happens when ambient temperature of air inside suspension drops to 30-40F or lower, obviously leading to a lower air density and thus a smaller air volume in the suspension which causes the car to set lower.
**For the record, these measurements were taken at temperature of 32-35F. I expect the contraction to increase by another 30% based on air density at 15F or lower, meaning another 0.25 inch for a total of 0.75 inches at colder temperatures such as 20F or lower.
Based on this, 0.75 inches of height difference is within design parameters, however, for those who experience more than 1-inch of height difference overnight, i would encourage them to test for any potential air leak especially during summer or when temperature is not that low. Suspension drop is fine in cold, but in summer it should be minimal

If you experience a height drop that's outside the normal numbers/parameters above, It's likely that there is a leak somewhere.

carlosinseattle

Well...the good news, if you can call it that, is that it's most likely not a strut. If even on both sides or all 4 then it's a check valve in the system, which is normally easier and cheaper to replace than a strut. I cut my advanced suspension ownership on my 2001 S600 and before that a 1995 Infinit Q45a, with the "A" standing for active suspension. Both cars used hydraulics, not air. But the principles are the same. I hope this doesn't push you faster into theworld of W223 ownership...

Donnymac

Once had this problem before. Visually obvious drop but also rise on startup.

Each night and morning, I would measure all 4….from floor across axle c/l up to fender lip edge. Nothing was consistent.

Fix was a combination of struts, maybe compressor and valves. Wasn’t rocket science but not a job for a rookie tech w/o supervision. Went back with reman parts and all good after that. At the time, all covered by third pty warranty. Problem never again surfaced.

FYI…Problem can get worse and strand you.

SW20S

I remember this, thank you!

Measured this morning, so it was parked about 5:00 and its now 10AM, so 17 hours and I measure 28 1/8th inches, so overnight it only settled a little over 1/2 inch.

JohnLane

Hmmmm..... Airmatic cars I have had only ‘settled’ when a leak was present.

SW20S

Every air suspension car I have had settles somewhat...

S_W222

If it settles to a certain level that is 1-inch or less, and then never drops further, I think it should be fine. From what I read at that time, anything between 0.25-0.75 is absolutely normal (especially if it stops dropping any further after the 12th hour during the 1st 48 hours). I had to keep it parked for 2 days at that time, just to do the test, and to confirm that it was only that initial 0.5" drop after 12 hours.