Rear Air Spring Question
I’ve replaced the front air struts with new bilsteins and would like to refresh the rear as well. I will be replacing the shocks and the springs, however I see that the subframe will have to come down to remove or install the Bilstein springs/reservoir. I do not have the tools to accomplish that.
The fronts I replaced were arnotts, it’s a night & day difference between the worn out arnotts and the new bilsteins. What do I loose if I went with the arnott ARN-A2725? Will the ride quality difference be as noticeable as the front ?
Is any part of the ADS system in the springs ?




The reason I was asking this question was because the drive quality of the car always felt weird, my lowered m5 project car with shot front suspension rode smoother.
When I had bought the car the previous owner had replaced both the front air struts with Arnott remanufactured air struts, and on the rear only replaced one side with an Arnott (which I know is a no no, should be replacing in pairs). I ended up replacing the entire suspension on the front end except for the shocks & sway bar, but it did not make any difference.
Recently one of my friends ended up buying an E55 which has new Bilsteins all around, it rode so much smoother than mine. I bit the bullet and got the genuine Bilsteins for the front and what a difference it has made in how the car feels. The Arnott struts were less than 2 years old and had less then 10k miles on them.
With that in mind I wanted to see how much of a difference would it make on the rear end, if anyone had any experience going to Bilsteins air springs from Arnott air springs.
I already have new Bilstein shocks for the rear end, just haven't tackled the job as I wasn't sure about going with Arnott A2725 air springs instead of the Bilstein with the reservoir.
The reason I was asking this question was because the drive quality of the car always felt weird, my lowered m5 project car with shot front suspension rode smoother.
When I had bought the car the previous owner had replaced both the front air struts with Arnott remanufactured air struts, and on the rear only replaced one side with an Arnott (which I know is a no no, should be replacing in pairs). I ended up replacing the entire suspension on the front end except for the shocks & sway bar, but it did not make any difference.
Recently one of my friends ended up buying an E55 which has new Bilsteins all around, it rode so much smoother than mine. I bit the bullet and got the genuine Bilsteins for the front and what a difference it has made in how the car feels. The Arnott struts were less than 2 years old and had less then 10k miles on them.
With that in mind I wanted to see how much of a difference would it make on the rear end, if anyone had any experience going to Bilsteins air springs from Arnott air springs.
I already have new Bilstein shocks for the rear end, just haven't tackled the job as I wasn't sure about going with Arnott A2725 air springs instead of the Bilstein with the reservoir.
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As to the rear Air Springs, since the Air Ride Control Switch in essence sets the Compression / Rebound to one of 3 settings, and since those setting features would be applied in the case of the rear end to the Shocks leaving the Air Spring to vary in accordance with ride hight presets, my worry would be that perhaps the Arnott may not work as Mercedes intended. That said, the Control Switch Features should work! I ended up dropping the whole of the rear subframe by disconnecting the e-brakes, Air Lines, and separating the Drive Shaft from the rear Diff. I used a Tranny Jack under the Diff ( after fashioning together a brace to stabilize the Diff ) to lower the whole rear end.
Removed the entire Subframe to replace all the Bushings for the Subframe to Car as well as those of the Arms (see shiny Poly KMAC replacement bushings), the Rear of the Differential, the front Diff Carrier to Subframe, wheel carrier to Torque Arm Bushings!!
Rear Subframe Installed with new UPD Rear Toe Arms. Notice all the alignment marks I made making sure to install those huge bushings just where they needed to be!!
My DIY Subframe Bush Removal Tool! Same tool used to replace all the bushings.
This is after 10k miles, still going strong!
This is what the Racing Brakes looked like when they were newly installed.
Last edited by E63007; Jul 30, 2023 at 07:06 PM.
It is fine if people want to go to the trouble and expense to use the OEM air springs. I just do not want people to be afraid of going the Arnott route because they are worried the settings won't work or they are too harsh. Just my $.02








