cad1857

Hello. My 2012 S550 4Matic's FRH end was totally collapsed and wouldn't rise after the car started. Car Too Low error message would come up when driving. The rear wheel well on the same (Right-hand side) was lower too, but nowhere near as bad as the front-end that had totally collapsed. I replaced both front struts (right and left hand sides) as they recommend replacing them in pairs. After new struts, it appears to be working fine. No more error codes.

However, the right-hand side of the car--both front and rear--are still about 1CM lower than the left-hand side of the car after I have replaced both front struts. The difference in height between right- and left-hand sides is same for both front and rear wheel wells. What could be causing this? I had taken the car for diagnostic to a Mercedes dealer for diagnostic before I replaced struts. They noted "INSPECTED ALL LEVEL SENSORS. FOUND BOTH FRONT LINKS ARE SEIZED, REAR LINKAGE IS SEIZED. STRUTS HAVE PROTECTIVE BOOTS COVERING THE AIR SUSPENSION BAGS. RECOMMEND REPLACING BOTH RIGHT AIR SUSPENSION STRUTS, ALL LEVEL SENSOR LINKS BEFORE FURTHER DIAGNOSIS."

1. From the symptoms, does it sound worthwhile to replace all three level sensors (replacement part: Arnott RH3501) as recommended by the dealer?
2. From the dealer notes, do you recommend replacing rear struts too, or just keep using what I have?

Thanks much!

BOTUS

you MUST replace the level sensor link rods (the sensors themselves are seldom an issue) these link rods are by far the weakest link in this system - these have a penchant to seize solid in a 5 year cycle even if you lubricate and try to keep them moving freely - they are $30 each and the fronts are simple - the rear is an utter nightmare to do

if it collapses for whatever reason or you go over big bumps / raise the ride height using the button when a sensor is seized, it will bend and can fracture little links on the mounting brackets. First giving odd ride heights and behaviour and then they will totally fail and snap off and usually collapses to the floor - although some strange one's manage to raise the back to max height

cad1857

Thanks!
I am rethinking my choice to stick with air suspension. There are so many parts, and troubleshooting can be expensive. For example, the car is now going down when it sits for longer period. Very slow drop (mm or less per day but it's there visually and measurably if observed over 24+ hours). What's next: valve block? compressor? all air lines? Very frustrating.

What are your thoughts on converting to Arnott Spring Suspensions? C2956 or C3272? Would the ride quality really be that worse than air struts?

Arrie

You say the right side of the car lowers very slowly so does this mean the car first is at the same level on both sides? If it is, the level sensors work fine as the car use them to set level. But then right side slowly goes lower, so it means you have a leak on right side, either front or rear.

When I replaced my 2013 S-Class springs I had the left front go down with the new spring. Before going to too much trouble trying to find a leak in tubing and valves I made this simple tool in the below picture. This is a hand valve that I connected between the new air strut and the air tube that connects to it. After car was up all the way to set level, I closed this hand valve and in just one hour the brand new air spring went down. FCPEuro sent replacement part even before I sent the faulty one back to them and they sent free return ticket for the part as this was faulty part out of the box. Everything was fine with the new part they sent to me until my car got totaled just one or two months later.

I had purchased also rear springs that I never had a chance to put in that car, but now I have another car that is a 2012 model with the exact same options I had in the 2013 model. I will put the springs in my current car as I believe they are the same part between 2012 and 2013 model years.





Keep the Airmatic. Remember, the car is 10+ years old and this is now probably the first time for trouble. Fix it and be worry free another 10 years...

cad1857

@Arrie

The car is lower on the right side to begin with. Even when it's been running and all. The right side (both front and rear) are about 1CM lower than the left side. That is likely due to fault in sensor mechanism--as also noted by the dealership in their diagnostic report (please see my first post for a quote from the diagnosis). What I am grapling with now is that in addition to faulty sensors, there is also a *slow* leak somewhere. After the car has been sitting for about 48 hours, it has dropped about 1CM on ALL sides. I initially thought that it was only on the right-hand side but now it appears that all four corners drop when car sits for 24+ hours.

It could point to a leak in system components such as compressors, air lines, valve block. But get this....before I put in the new struts, only the fault struts end was dropping. So may be the guy who put in new struts didn't do a good job. However, I did see him spray soap water on new struts' air connections to see if there was a leak.

It's getting to be a mystery ball....

May I know why you advised against converting to coil springs?

Thanks

doni01

iTrader: (1)

It is not a mystery ball. What parts did you use for the replacement? I bet they weren't OEM's. I believe that is your issue. Valve block and everything else just doesn't fail at the same time with your leaking struts.

Arrie

Then, if the car is lower on right side at all times it could be the right side front level sensor. If car changes level when using the elevated position then the sensor works, it just is that the level setpoint has changed. This can be from the "fact" that the sensor link froze. If it did it could have caused the sensor bracket to deform a little that then makes error to the level "zero" position.

Re-leveling the suspension should take care of this.

But this has nothing to do with the whole car lowering and the fact with that is that not all four springs or lines to them or the magnetic valves fail at the same time. Are you sure you are not just seeing the car level change due to temperature chage?

cad1857

I didn't use OEM struts. They were bought from AutoShack. Came pretty well reviewed.

cad1857

Kindly explain the correlation of car level change to temperature change? It's been getting hotter over the past couple of days where I am. Does hotter weather make them lower (or lose air)?

Arrie

No, it should make it go higher but I think if that happens the system lowers it back down and then if temp is just a bit lower so is the car.

Arrie

It does not matter who build the struts as long as the height of the car is controlled using the level sensor data for it like these systems do. You could feel difference in how stiff the air spring is but for the level it does not matter.

BOTUS

1 cm could well be the effect of 10 plus years of wear and tear and calibration that was average at build

they can go up and down at least an inch overnight if atmospheric temps and pressure vary enough - in a cold winter night it will drop up to 2" (and its not a leak as no maint 5 years on it will be right in the summer and dead stable if the weather is stable)

ChrisHimself

Can you inspect your sway bar links for me? They can jam up sometimes and those things are good for like 3 years of driving in some cases depending on how hard you are on cars (me)

Anhhoaitthanh

https://shockabsorberpro.com/how-res...ic-suspension/