Hi folks,
I posted this in the Non-AMG R230 section a few days ago and thought I would repost here just so it will show in the search results since the ABC systems are the same.


I had the infamous symptom of my SL500 losing pressure in one of the shocks when parked. Sometimes it would be fine, sometimes it would sink on the left front after a day, and sometimes it only took a few hours. According to my MB star manual, the updated "fix" from MB is to replace the hydraulic filter as the first step and then move on to a flush if that does not fix the problem etc. I got a quote for a flush from the dealer for $700 and said to hell with that.

So last weekend I decided I was going to do a filter change and pull out the front axle valve unit and clean it. I also ordered 3 L of Pentosin CHF 11S and refilled reservoir to correct level when the job was done.

To begin, I opened the ABC reservoir and sucked all of the fluid out. Closed it up and raised the car to bleed the system. The rest is explained in a short video a mechanic from Autobots Automotive Repairs in Vancouver. Very helpful. I also had the procedure in my STAR manual.


Here are some pics:

The valve unit is located in the left front wheel well


The valve unit removed




Valves removed



Block wasnt too dirty on the inside but a nice solvent bath didnt hurt





Block cleaned in solvent tank





Valve unit reassembled



Unit re-installed



If there is any advice I can give its just this:
-Pay very close attention to valve placement while disassembling and take plenty of pics of the color coded hydraulic lines and electrical connectors in case you forget
-be very careful with the plastic retaining clips on the valve unit. They're brittle

Also, in the video it says 1.5 hrs of labor. Maybe if you have a lift and you've done it before. I spent 6-8 hours on everything but I tend to overdue the cleaning and n\get side tracked easily

So far so good. Have not had a problem with it sinking on any strut in the past few days and have driven it several times. Feels much better.

Also added some LED License plate lights from fleabay. No error codes as advertised and theyre super bright and blue!





Cheers!

 

Great job

 

Great post - Doing this as well... Great pics FLGSHP7

 

suppose i should put this on my to-do list also. thanks for the write up. did you replace the seals also? i assume they are available from the dealer.

 

I did not replace the seals. I wanted to but didn't order them ahead of time. Now I know what I need to order. There were two that should have been replaced. All of the internal O rings on the valves were in perfect condition. I have no leaks and haven't had so far. Car is still riding great and no sagging on any shock so it was a definite success. Read your entire build thread last night OZ. Youre a freakin animal man. Do you ever sleep?!? Can't wait to see it finished!

 

lol. all that car work has finally been catching up with me, took a couple days off but back on it tomorrow. hopefully taking wed-monday off between jobs so it will be one of the last hard pushes to get it painted. then finish exhaust, mount my widebands...............yup, still more to finish even after paint. lol

i have not had problems with my car sagging, but if left to idle in park for awhile it will raise slightly by itself, then go back down. not sure if cleaning that valve assembly will fix that, but it had me tripping when i was originally looking at car to buy it. would park it, and the fender gaps looked good, turn around and talk more, then look again and it was raised!

 

Mine did that too actually. I forgot to check it but I can't recall that I've noticed it since. Haven't really paid close attention though. I will check next time I take her out and report back. Hopefully this fixed this issue. I was talking to an Indy that always worked on my Bimmers and he had an SL in the other day that would only raise on one shock...when the car was off?! The only reason I can see for this is the pressure reservoir leaking past the valve. Or maybe he was just sinking on three haha.

 

it would usually take 5 or so minutes for me to notice it, so it really wasn't a big deal and hardly ever did it. driving around it always seemed to be just fine though.
might be good to do it as preventative maintenance though.

 

Honestly if you're not having any problems with sagging I would just change the filter and check your ABC fluid color/smell. You sound like you have enough on your plate anyway lol.

 

i will check those out also. thanks

 

On seals- once you are in there- replace them. We wrote on the subject in another thread- do a search. A harbor freight o-ring set has everything you need to the job right.

 

Hi,

Your information is very timely as I am noticing my car sags after three days or so.

I typically start it up and raise it via the "lift buttons" and everything is fine until I leave it parked again. I was told this was do to the valve blocks leaking in both the front and possibly the rear.

I am thinking your information would allow me to clean and change the O rings for the valve block in the front and to stop the leaking of the fluid which causes the sagging... correct?

You mentioned "shocks were sagging" so I am just trying to confirm my thoughts...thanks!

 

There were two outside seals that needed to be replaced. But they were not O-rings. More of a gasket. Definitely a specialty item. I actually went to the hardware store and was going to replace everything. But then I changed my mind. There was not any sign of wear on any of the O-rings and I found close matches but I just didn't feel comfortable throwing a "close" O-ring in there and possibly/probably one of inferior quality. I mean, who knows a how a harbor freight O-ring is going to stand up to hydraulic fluid? Not to say that it wouldnt work. But I would rather find an OE seal set or get some help from a seal company and put together a list of what one needs that would comply with the conditions they would face.

 

Do you have any visible leaks on the floor after driving the car?

Most likely it is an internal leak. That's what it usually is. As I stated in my OP the MB STAR manual calls for a filter change with the one strut sagging symptom. However, it cannot hurt to clean up the valve block. Your fluid color is a big deal as well

 

the oem o-rings and gaskets are not serviceable from mb. there is no rebuild kit.

i have done the hf o-rings on a couple of my friends' cars and one of them has 60k miles and several years without any problems.

 

Thats good. Do you have any idea where to get the gaskets shown in my fourth picture?

 

Great write up! Thanks – will do mine later since they seems to loose pressure over time ….

I have wanted to get into this subject but as I’m pretty occupied with the renovation/build of the engine the time has not been right …. even so …. here’s a site from eBay where they seems to know there business …. Some background info. on the troubled ABC system … seems it’s like a Swiss clock …. and have to be cared for in a nursing manor ….. Something MB forget to put on the maint. schedule!

Sorry about the length of this post but as the original is in German I have allowed myself to translate it to English for you all in the best intension … used the all good Google Translation …. here we go:

Active Body Control ABC suspension Care - Cleaning and CL 55 AMG Kompressor
It consists of a fine filter (3 microns) of Mercedes Benz (A0031846101), specifically for the ABC suspension - cost € 39.00. Factory in your vehicle is a 10 micron filter is installed.
Also included in the kit are our magnetic filters. This filter can be repeatedly cleaned and is therefore a unique acquisition. The casing of the filter is transparent, so you can always check the color and therefore the quality of your Pentosin oil - cost € 99.00.

Why the care of the ABC suspension is so important:
Over the years, the oil is dirty, thereby the components such as the hydraulic pump, and valve units Suspensions destroyed. You can check your oil quality easily. Pull the dipstick out of the reservoir, this is next to the white filter. Take a white cotton cloth and strip the oil in the cloth. Good oil is green, light brown is still flushed and dark brown to black oil - must be completely replaced immediately - usually with a burned smell.
The Pentosin oil for the exchange we have in 1 liter bottles on offer. If you do not want to buy this with the purchase of cleaning and care, liter is € 17.95.
The system comprises about 15-16 liters Pentosinöl (A00198924003-10). To replace you need about 10-12 liters, for everything you do not get replaced. In the struts still remains old oil. But this is not a problem at first. What is interchangeable, please replace. Block next to the fine filter. The vast new oil mixes with the old waste oil. The fine filter cleans most of the oil mixture.
After about 1000-2000km return to check the oil paint and possibly repeat the described procedure until only green oil in the system.
From our own experience we know that if all 20,000 30,000 km oil and fine filters are replaced, there are no problems. We drive an S Class W220 S55 AMG Compressor with 370000km mileage and have never had a defect in the chassis - even the struts are original.
The sets include a magnetic filter was developed by us. This filter is designed for metal abrasion of all components of the ABC suspension and the metal shavings that form during the destruction of the ABC hydraulic pump. Without the magnetic filter metal debris and the dangerous metal chips enter into the whole system, because they are rinsed again with the oil circuit.
If metal chips are in the ABC system, it is necessary to disassemble the entire chassis and cumbersome to clean by hand!
With the installation of a magnetic filter to prevent this procedure. Through the clear case you can as you open the hood checking the color of your oil and check whether foreign objects. The Fiter is washable, thus making a single purchase. In the event that's going something broken, all parts can be ordered individually.

Important for long-lasting durability of the ABC chassis is clean oil.
In the last picture you can clearly see how an ABC pump is 200000 km completed in a clean chassis system looks like. In the pictures above the pump runs for about 80,000 km in dark brown oil. Of metal debris in the oil has ensured that the oil to liquid sand paper and rubbed it all broken - with every km was driven. Moreover, by the poor oil increased friction, especially in the ABC pump arises. High friction means more heat and therefore pumps are sometimes so hot that you can overheat and glow while you drive. You are in mostly black - purple and the system smells of burnt oil.
Dirty oil slowly destroys first of all the ABC hydraulic pump. Many of the errors resulting from the suspension at low pump pressure. If the pump pressure of 200 bar actually dropped to 120 bar, you get the first clue as to learn from the display Kombiinstument. The message is white / black and is "ABC defective, please visit workshop".
If you still need to move the vehicle and continued to work the pump, the warning message will appear after a certain time in red, the pump pressure has dropped below 90 bar and the ABC Fahwerk goes into emergency mode. It closes the stop valves in the valve unit, so that the vehicle does not fall down. Your vehicle is in such a way as if the shock absorber is defective.
Unless this emergency mode still works, you can and must eventually move into a workshop.
The reputation of the ABC suspension is bad, simply because the care is lacking and it is characterized zerstört. Regelmäßige care maintains the ABC suspension for a vehicle of life, it was developed.

http://www.ebay.de/itm/261122174475?...84.m1438.l2649

also this one you prob. know of: https://www.arnottindustries.com/par...ENZ_yid18.html

My comment on Pentosin CHF 11 S Hydraulic Fluid is to buy 20 l. – this way it will be the cheapest …… you will need 16 l. for a total rebuild/renovation.

 

i stack two new o-rings. works like a charm.

 

Thanks Amok, I tried and finding that 3micron filter even my dealer didnt know anything about it. Of course they also wouldnt sell me a star manual...

And haha alx. That's genius. If it doesnt leak then its a success, right?

 

Yup. Remember- better two have two smaller seals than one big one. Now where is my smug face...

 

https://mbworld.org/forums/sl55-amg-...ock-boots.html

or direct link: http://www.startekinfo.com/StarTek/o...stedDocId=9124