gremlins in rear, airmatic suspension
11-09-2018, 10:57 AM
#1
Junior Member
Thread Starter
gremlins in rear, airmatic suspension
We recently purchased a very clean 2006 s500 with 105,000 miles on it. We've put another 3,000 miles on it now and I've noticed a few things that might need attention, but I need some direction.
One morning, I went out and the rear, passenger side seemed to be sitting a little low. Lower than the rear drivers side. I got in, closed the door and started it. There was no warning light on the dash. I got out and checked and it was still lower than what I thought it should be and definitely lower than the driver side rear. I got back in and hit the button to raise the suspension. The light came on that it was raising and I could feel that it was. The rear passenger side had raised, but only to what I thought would be a normal ride height. The rear drivers side was much higher. I got back in and lowered it back to normal. Again, I could feel it working, and again, it seemed like the passenger rear was sitting way too low. I backed it up about 10 feet and put it back in park. I heard the compressor and could feel the car leveling When I checked, all tires seemed to be at a normal ride height.
It has happened a few times. I have noticed that it is sometimes the rear drivers side sitting lower. I can go through the same steps and it corrects itself, but it is almost always the rear, passenger side.
No problems with the front at all.
The fact that it happened on both sides, even if it usually happened on the passenger side, lead me to believe, through some research, that it could be the valve block on the pump.
I talked to a friend that worked as a Mercedes mechanic for years. He suggested that if there is a leak, that it most likely will be in the strut itself. He said it could be the control valve, but that he had only seen a few fail. He said the usual spot is inside the strut, as the line bends around. He suggested raising the car when we got home and leaving it up overnight a few nights. He said that if it stays up, its probably the strut. And if it still drops, it might be something else.
I did what he said and the next morning, it again seemed to be sitting a little lower on the rear passenger side.
The next two nights, I raised the car before I parked it and it stayed up.
Last night, I left it in normal ride height mode and parked it. This morning, it was the drivers side that seemed low.
There are no warning lights on the dash and once it corrects itself, its never drops during the day.
Maybe normal? My friend said a scanner would tell him a lot more, but he doesn't work for Mercedes anymore.
Any thoughts would be appreciated.
One morning, I went out and the rear, passenger side seemed to be sitting a little low. Lower than the rear drivers side. I got in, closed the door and started it. There was no warning light on the dash. I got out and checked and it was still lower than what I thought it should be and definitely lower than the driver side rear. I got back in and hit the button to raise the suspension. The light came on that it was raising and I could feel that it was. The rear passenger side had raised, but only to what I thought would be a normal ride height. The rear drivers side was much higher. I got back in and lowered it back to normal. Again, I could feel it working, and again, it seemed like the passenger rear was sitting way too low. I backed it up about 10 feet and put it back in park. I heard the compressor and could feel the car leveling When I checked, all tires seemed to be at a normal ride height.
It has happened a few times. I have noticed that it is sometimes the rear drivers side sitting lower. I can go through the same steps and it corrects itself, but it is almost always the rear, passenger side.
No problems with the front at all.
The fact that it happened on both sides, even if it usually happened on the passenger side, lead me to believe, through some research, that it could be the valve block on the pump.
I talked to a friend that worked as a Mercedes mechanic for years. He suggested that if there is a leak, that it most likely will be in the strut itself. He said it could be the control valve, but that he had only seen a few fail. He said the usual spot is inside the strut, as the line bends around. He suggested raising the car when we got home and leaving it up overnight a few nights. He said that if it stays up, its probably the strut. And if it still drops, it might be something else.
I did what he said and the next morning, it again seemed to be sitting a little lower on the rear passenger side.
The next two nights, I raised the car before I parked it and it stayed up.
Last night, I left it in normal ride height mode and parked it. This morning, it was the drivers side that seemed low.
There are no warning lights on the dash and once it corrects itself, its never drops during the day.
Maybe normal? My friend said a scanner would tell him a lot more, but he doesn't work for Mercedes anymore.
Any thoughts would be appreciated.
11-09-2018, 11:34 AM
#2
MBWorld Fanatic!
There several options of what the reason(s) could be.
1) Check the level sensor at the rear axle. It sits next to the differential, and tends to corrode.
2) Leaks, especially at the fittings, from compressor, valve block and struts. To be checked with leakage spray
3) worn out compressor. Pressure and air amount insufficient shoulb around 13-14 bar. Easily to be checked by opening the the air supply line from the valve block and attaching a manometer. Bridge the Compressor relay and let the compressor run for some time. Pressure shall go to 13-14 bar and stay for 1 hour or so.
If the strut would be leaking internally, it would not rise and stay up at all. And it would not switch between right and left.
1) Check the level sensor at the rear axle. It sits next to the differential, and tends to corrode.
2) Leaks, especially at the fittings, from compressor, valve block and struts. To be checked with leakage spray
3) worn out compressor. Pressure and air amount insufficient shoulb around 13-14 bar. Easily to be checked by opening the the air supply line from the valve block and attaching a manometer. Bridge the Compressor relay and let the compressor run for some time. Pressure shall go to 13-14 bar and stay for 1 hour or so.
If the strut would be leaking internally, it would not rise and stay up at all. And it would not switch between right and left.
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brian ruff (11-09-2018)
