ABC to Coilovers conversion: The Ultimate FAQ
 

Over the last couple of years there have been countless threads outlining ABC failure either at a strut level or complete system meltdown. Opinions get thrown around, engineers get flamed and the topic of converting the ABC system to a standard coilover suspension gets mentioned, acclaimed but never fully explored. Everyone always talks about someone who knows someone who has done the conversion but no questions are ever answered.

My car is a '03 SL500. I have been running coilovers for 5000 miles now so I'll answer any questions once and for all and let's see if we can make a sticky out this thread for future reference.

First of all, let's start with the ABC system.
Yes, it will fail. There are no "if's" but rather "when". The design isn't particularly brilliant and the pressure generated by the hydraulic fluid far exceeds what the seals on the struts and the pump are designed to handle. Hence once it fails, if fails massively. Furthermore, replacing all 4 struts, pump, block and lines will not only exceed the cost of a used SL in today's market, but it will inevitably also fail.

Where do you get the conversion kit?
StrutMasters SL500 Kits
There are two kits available.
The first is the Coilover system for $1595.
For an extra $200 you get a light fix module. The module is a series of resistors that will block the warning from the ABC sensors to the Comand system. That way rather than a flashing red warning that you cannot disable, you simply get a "Warning: ABC Display Malfunction" message that you can click through. Considering Mercedes charges over $2000 for each hydraulic strut, do yourself the favor and get the light fix module.

Do I need to modify anything?
No. The kit is a direct bolt on. They include the hardware to cap off the ABC lines at the struts. Other than that the coilovers mount at the same points your original suspension does.

Is there a kit available for my 55/600/63/65?
Unfortunately there aren't any kits available out there for the different R230 versions.

Is there a sway bar available?
If anyone has it, I have yet to find it. Would the car ride better with one? Absolutely. Does it ride well enough for me not to care? Absolutely.

How does it ride?
Let's start off the bat and say it: coilovers will never ride as smooth as a hydraulic suspension.
Once the ABC is off, you begin to realize just how heavy the chassis is.
The ride is tight but comfortable. The rebound on the coilovers is noticeable but not unlike an E500. All in all, it makes for a comfortable ride that is predictable under hard driving.
I have driven the car from New York City to Arizona with no trouble whatsoever and have logged on over 5K miles as of today.

Do i have a need to keep the ABC/Power Steering Pump?
The R230 has a tandem pump that operates both the ABC and the Power Steering system. A new pump is $1360 from Genuine Mercedes and even a used specimen will fetch upwards of $700 at a junkyard.
Luckily for you, once the conversion is completed there is no need for a tandem pump anymore.
I sourced a power steering pump from a 2001 S500 without ABC (any year W220 without ABC should do it).
Two out of the three mounting bolts line up perfectly and the stock lines from your R230 can be rerouted with minimal work.
Extra bonus: You get to use regular power steering fluid from Autozone or Walmart rather than having to track down CHF 11S at $30 a liter.

So there it is.
If you have any other questions, feel free to ask away and I will do my best to answer.

Nice write up! Thanx

good info...
 

good info here, i assume everything is still going good with this conversion?

Everything is still perfect.
Honestly I couldn't find a thing to complain about my new setup other than the occasional noise from the springs when traveling over speed bumps.
The power steering pump transplant is also working flawlessly.

All in all, if you have a failing ABC system and are looking for an alternative to replacing all components, I highly recommend the StrutMasters conversion.

was you able to remove the front/rear valves, hydraulic lines, etc.?

also, what about the dash light mod? did you purchase that as well?

I didn't go through the process of removing the valves and the lines as I have been driving the car every day and didn't want to have her off the road for too long. But it's just a matter of unbolting everything at this point really.

I did purchase the dash light mod. Once you splice it in, (extremely simple) all that happens is that you get a quick "ABC display not functioning". You just get to click through it.

Looks like I will be doing this my abc system took a crap tonight. Fluid all in the driveway ... No fluid in reservoir :-(

How many miles on yours?

77k
Fluid seems to mostly be coming from the front driver wheel well

Sounds like it's both the strut and the pump. It's located in the driver side above the wheel well.

The car hasn't dropped any height though. Still sitting normal . But I was leaning on the pump giving out. It's dark so I couldn't really check it out. But I was gonna swap out my system for a custom air ride setup in 6-8 months so I guess those plans just got moved up a bit.

Had the spill in the same place and it was the pump only. The ABC struts hold up much better than the Airmatic struts (on the S) btw.

I for one would rather replace the ABC parts than do a coil over; there are so many used/rebuilt parts around for the SL, so the cost is not too bad.

Having had two R231's, one with springs and one with ABC, there is no comparison between the two.

What R231 did you have with springs?

2013 SL550. Unlike the R230, ABC became a $4k+ option and it never dawned on me to check of what the default was. Somewhat thought that it would be Airmatic rather than springs (like the S).

The ride was firmer than ABC with more bounces and body roll, which increased by lowering the car with H&R sport springs. The car was crazy high with stock springs as well.
Problem is you can't raise the car at all for the driveway, etc. ABC is worth every penny IMO.

Here is a pic of the SL (lowered)

If it's just the pump I will replace the system cause it worked great till it took a crap last night. I need it to be able to go up and down cause of my driveway and to protect the black series kit. If it's not over 2k to fix I repairing the stock setup cause I liked it. If it's more the 2k I am gonna go aftermarket air ride setup.

What you are saying somewhat makes no sense. Only ABC allows you to raise the car or have easy ride height control either via links or lowering module.

This is especially important if you go for a kit that requires the car to be quite low to look good.
Plus if your pump is shot you still need to get another power steering pump (as suggested by the 1st poster).

So wether it's over or under $2k, ABC is the only thing that will work for you correctly.
Also had a 2005 SL600. Love the torque, but a car like that is about $4-5k a year for maintenance/repairs. Never bothered me; just part of the package ;)

Yeah if it's just the pump I plan on keeping it as is and just repair. My buddy converted his to coilovers with airbags on top so he can still raise and lower the car. It's a custom setup done by a shop here in Houston and they also have the abc light fix. And I know the maintance is high on these cars I don't mind that. It just seems that the abc system is ultra problematic in these cars. I am not looking to keep resale value . So I don't mind switching to a custom air bag setup if needed to . I love the car just not the cost of the abc

Hi.
A bunch of nonsens in my opinion. Here they would send everyone who does it to jail, for causing such a risk to other people.:wall:
But anyway, if somebody cannot afford to maintain the car properly:
The SL350 has regular coils and of course a swaybar.
At next, the ABC electronics can be removed from the car system by coding, but apparently the "Vendor" also lacks experience in this field.

Cheers, Frank

I was curious about doing this also on my SL65 and i'd figure if an SL65 Black Series uses coil overs maybe there's a way to get rid of any message that would show up, that is until my indy and performance shop told me about arrnott struts which have a life time warranty as long as you own the car (doesn't transfer when you sell the car) They basicly rebuild the strut, so thats my plan once my struts start going out. They only charge 700 per strut when u give them the old OEM strut and I have about 30k in warranty left so I think I'm gonna go with that option, $2,800 for lifetime warranty struts isn't, esp. when my warranty will cover it lol

Hey guys. I will be completely removing ABC from my vehicle in the very near future and am replacing my suspension with a custom alternative :)

I'll keep you in the loop, but all major ABC components (pump, valve blocks, accumulators, lines, and struts) will be removed from the vehicle. I will be using W220 lower control arms in the front to utilize W220 sway bars front and rear. My power steering pump will be replaced with a non-ABC W220 one. ABC will be completely eradicated from SDS, and not just superficially removed.

So will the sds remove it so I don't need wiring things. I have the sds 4 set up and I just got to do engine and car myself and save from diagnostic fees mer benz charges to much. But want to do coil over and not need wiring. Can I remove computer s and level sensors. I know doing the hydraulic system and removing it is okay but what about sensors. Level sensors and speed sensors. Mine is a 2003 s600. And I use it for the mb amg race meets and drag the car. So sway bars are my last concern. And will not use them cause I want the soft ride. And only going fast in straight line. And doing cause done. car was flawless till 103, 000 miles now right strut and speed sensor and pump and a line is showing leaking. But my big question is Arnott makes a airmatic kit and strutmasters and some company on ebay. Arnott is great company but most don't use their product cause it says airmatic. But strut masters says life time but not normal wear. Arnott don't care if strut goes out 20 years from now it's covered. So anyone know if valving or spring rates are better on either. Talked to strut masters they said it's spungy. Arnott never tested with no sway bars but no-one has spring rates or adjustable struts. Atleast that they will tell me without buying and testing myself. So any info from anyone would be great. I just fixed my car after strut line and speed sensor and now pump went out week after it all got fixed yeah great system. O and it was flushed and filters changed and metal magnet one since 17, 000 miles so with that much maintenance not fixing more cause it's done. So help please. :(

And flush was every year or 10, 000 miles never missed a flush but. Bad parts. And just need help picking a kit or tell me where to get a custom set up for racing that I can turn knob for track to change valving and stiff and and back to soft when leaving. And spring rates just need higher rear for launching at hole shot on slicks. Sorry a lot of questions and not many to help.

Electronic hell (sort of)
 

Found this thread when I Googled my question below. It's not addressed in the thread or anywhere else I've looked, so far. So here it is. I drive a 2001 R129 SL600 with 166K on it. The ABC pooped at around 95K & I converted. I had someone else do the work since I'm not a DIY guy anymore. (Used to be a half-assed motor head with too little knowledge but a willingness to figure stuff out. Don't have the facilities or the time to DIY anymore). I have worked with 2 mechanics over the life of my car. The guy who did the conversion for me is smart but not an MB guy. He has no way to read the codes to track down complex problems. After I did the conversion, I lost stability control (ESP) & traction control (ASR) & anti-lock breaking, He assured me that there were no sensor wires on the old hydraulic units that were removed along with the units. He says the malfunction is not due to the conversion but, since he can't get the codes, he can't help me figure it out. This guy is very bright & could likely fix it if he had the "tools". I also use an MB indy who has access to a Star computer. I give him problems that require a Star computer for diagnosis. (I never go to the stealership). The MB indy says I screwed myself when I did the conversion because there are sensors on the hydraulic units that are critical to the ESP/ASR/ABS. He says that removing the units resulted in my losing the 3 electronic systems & I can't get them back. So I drive a very electronically unassisted car as far as the suspension/brakes go. Things get interesting when I drive in snow, for example. But I went to school in Syracuse, NY where it snows every day during the winter. I drove a 1969 Pontiac Firebird 350 then - no assisted anything except power steering. So when I lost the systems on my SL, I retaught myself how to drive without the electronic nannies. But I do miss them & the measure of extra safety they can provide. Years ago, the ESP saved me from a likely expensive repair when I was unaware that a rear tire was going flat. I entered a turn at a good clip. The car started to lose its line but the ESP took over & saved my ass. Anyway, I digress. I'm not sure I believe the MB indy's assessment but I can't seem to locate the solution myself. Seyath, I thought maybe you could shed light on this even though you drive an R230. I would be grateful for some direction. Thanks in advance,:bow:
Joe

Joe, your car had a suspension system Mercedes calls ADS II (Adaptive Damping System). It is similar in function to the later Airmatic system; the primary difference is one system uses pneumatics, the other uses hydraulics.

I believe he is mistaken. There are no sensors on any ADS hydraulics. There is a sensor for vehicle level on each axle and three body acceleration sensors. That's it. So I suggest asking this indy to be specific about which sensors he believe are now missing from your car.

Has something as basic as initializing the steering wheel angle sensor been done? This involves simply turning the wheel full left and then full right.

Possible solution: purchase a Chinese-cloned Star Diagnosis system for around $300. Give it to the other mechanic to use, or use yourself to check for faults in the ESP system and follow whatever diagnostic procedures are indicated by the ESP diagnostic manual (likely found on the hard drive the Chinese sell you; also found on the R129 Tech DVD).

Rod,
You're a life-saver, and maybe literally so. The existence of a Chinese-cloned Star system is invaluable. Do you know the web address? Either way, I finally have a lead.
Regards,
Joe