Hello, I'm new to this group, but have used some of the excellent maintenance and repair threads from time to time and thought I would give back to the group with a report on converting my 2006 W220 S430 from the OEM Airmatic air strut system to the Arnott coilover strut conversion.

My S430 has almost exactly 75k miles, and the Airmatic system was leaky, and as a result, my compressor had been overworked to the point of failure. Arnott has replacement parts for the entire airmatic system, but the cost of replacing all the struts and the compressor, seemed like a lot, and given the likelihood of future leaks and compressor failures, I simply did not want the Airmatic hassles. Sometimes less is more, and as it turned out, this is one of those times.

I actually found out about the conversion kit from a thread on MBworld and also looked at the Strutmaster website before deciding to buy the Arnott system. I chose the Arnott system because their website looked more credible, literate and professional. The Strutmaster site seemed like some kind of folksy sales job, and it did not seem well organized to deliver pertinent information upon which to make an informed decision. In particular, the Strutmaster site seemed a little hazy on whether they would or could provide a system to disable all warning messages which would undoubtedly appear after converting from the OEM air struts to the coilover system. If you are going to invest $1400 or so into your car, I want to be sure of the quality and that there will not be any "warning light " issues. Arnott uses Bilstein struts (apparently, although there are no labels on any of the struts that say they are Bilstein) which I believe have a reputation for quality. The Strutmaster struts are of unknown origin and cost only a little less, maybe $200 to $300. I thought the extra cost was well worth it.

I found the people at Arnott extremely professional and helpful. They were informative about every question I had, and were interested in my successful installation.

I am not a professional mechanic, I am an occasional home garage guy. I have no experience with any suspension issues. I was concerned about being able to handle the job, so I carefully looked at the installation instructions before buying the kit to see if it looked like something I could handle. It looked pretty straightforward so I bought the kit. The cost, including shipping was $1683.52, which includes a $300 core charge, which is refunded upon return of the old airmatic struts. (The return freight is included in the price, and the kit comes with a prepaid UPS return label, making the return extremely easy). I will report if there are any problems with the refund, I have only recently returned the cores.

I thought the installation would take a weekend or so, but because of my inexperience and because the instructions lack some detail, and because of some tools I needed that were not noted in the instructions, the project took two weekends and two evenings. I have some some installation tricks and advice to give anyone who wants to do the installation, which I hope to post at a later time.

I want to report that I am extremely pleased with the kit overall. The car rides beautifully, much better than the Airmatic struts it replaces. Somehow, Arnott got it exactly right with a perfect balance of ride comfort and performance. Bear in mind that I am not a sports enthusiast (It's a luxury car, for god's sake!), but, after taking it to Santa Cruz on Highway 17, I can tell you there is superior control, precision steering and overall better handling than the old Airmatic struts. I am very glad I made the conversion. The car itself is MUCH BETTER!

I look forward to freedom from Airmatic problems, including electrical problems. I previously had a battery drain problem that I believe was caused by the compressor working to keep the ride height up while parked, and while driving. The compressor has to use a lot of battery juice. I'm glad that is a thing of the past. Again, less is more here.

Some have asked about the ride height and I would say the car sits a little lower in front and a little higher in the rear, giving the car just a bit of a nice rake. It looks entirely right to me.

If anyone is interested in knowing more about some of the installation tricks and traps, just post a reply, and I'll be happy to share what I've found.

All in all, I highly recommend this product for the W220.

 

Yes id like to hear more
It's nice to hear from someone who has actually done the conversion since all we usually hear are speculations from people who never installed it

 

Hi, are you considering the conversion? I think it helps with several issues. If you have leaks in your system, and you want to keep the Airmatic, you will have to identify all the leaks, and all issues with the compressor, struts, solenoids and computer. I didn't want to hassle that for the rest of the time I own the car.

If you are considering the conversion, the first step is to download the installation instructions on the Arnott website. I will try to post them here, but I don't know if I can.

Once you have looked at that, I can describe some of the things left out of the instructions. I think anyone who is reasonably good with tools can do it. And there's Harbor Freight for any tools you might not have.

For example, the instructions don't mention that you'll need a ball joint separator... usually about $16 bucks at harbor freight. And some larger half inch drive metric sockets and wrenches. And a #40 star driver for the rear brake calipers. The instructions call for a shop lift for the car, and there is a particular reason for this, (which they don't say) but you can use a jack and jack stands and do both front wheels at the same time, finish the front and then jack up both back wheels and do them after the fronts.

As I was inexperienced, I did not realize the importance, in doing the front struts, of disconnecting the control rod to the upper control arm on both sides at the same time. This is because both sides are connected with the sway bar, and you need maximum flexibility to be able push down on the lower control arm to get the struts to fit in the correct position on the lower control arm. It can appear like the strut needs to be compressed, but in fact, you have just enough flexibility to have a helper push down the arm as you insert the strut in place.

The back struts have the same issue, make sure you do them together.

I also found a trick to be able to push down the lower control arm without loosening the inboard bolt, as recommended by the instructions.

Hope this helps. Anyone going to do the conversion?

 

Can you post some pictures of the kit please

 

Great Post!

 

Wish I could, but the kit is installed now. I should have taken photos as I went, but frankly, I wasn't sure I'd be able to do it. And I was in a hurry to get my car back!

I will try to get some photos of the installed struts and post them.

 

Here are the installation instructions. Any questions?

 

I thought the airmatic fuse was relay O or N. Not F32.

 

Henry,
I just installed the Arnott conversion kit this past weekend, smooth ride, but steering is a lot stiffer, its almost like not having power steering....does it feel like your steering is harder after your install? 1AstroJoe

 

You need to reset your steering see the sticky threads

 

No, I didn't have any steering issues. Hope the sticky thread helps.

 

Given this result it makes one wonder why Mercedes elected to implement air suspension in the first place. One thing that I can think of is the ability to compensate for variation in the rear load. This is why mercedes retained the rear air suspension on the v8 W212's

 

I got the Stutmasters install recently and my stering is stiffer can you advise on the problem and the solution please.

Thank you.

 

What does ''reset your stering see the sticky'' means, I am, experiencing the same stering problem.

 

the thread at the top of this forum are "sticky " and always at the top of this forum because they contain important information

this thread
https://mbworld.org/forums/s-class-w220/342824-w220-s-class-owners-start-here.html

is where every w220 owner should start . There are links about how to do resets of the steering in that thread