MarkCan

To begin with,

The system was systematically serviced.

Struts were replaced as well as some hoses, valve body and the ABC pump.

There were few instances where the brief ABC warning would show on the dash while going over bigger bumps. Neither MBII scanner nor the Star system detected any faults. System flush made no difference, at least to the issue at hand.

From reading about it around here I notice lot of similar problems related to the ABC return accumulators. They were never changed so I decided to give it a try.

Ordered a set and replaced both, front and back. It is a straight forward procedure that been covered here in several treads. Providing you get the MB hydraulic line disconnect tool ($20) you can be done in no time.

There was very little loss of the fluid since the car was lifted of the ground completely. After initial inspection the old accumulators look good to the naked eye. Basically no different than the new one. Membrane still sitting high and looking to be in good condition.

Well, the worst case scenario here would be me wasting 125 bucks on parts not needed. But wait just a minute here, during the removal and installation process I notice a significant difference in the weight of the parts. After putting the old and the new on the scale one can clearly see, there is almost a pound in difference. I think you all know where I’m going with this. Membrane was leaking and they were full of fluid.

Needless to say the ABC warning never came back again.

mikefamig

I did a Google search and found what I think is a nice troubleshooting guide for the ABC system so I'm sharing it here .I have a 2005 SL500 that sags on one wheel when parked for a period of time so I'll be looking into it when I get time.

http://mercedes-abc-drive-carefully....y-part-of.html

Mike.

MarkCan

Get ready to rebuild your valve block. You can buy the seal set and do it yourself.
Happy wrenching 😉

bobterry99

This could be completely normal -- or not -- it depends upon what your concept of "a period of time" is.

If you conclude there is a problem, then two back-to-back Rodeo routines may correct it. A Rodeo followed by a fluid flush would be even more effective. Rebuilding the valve block is a last resort. And doing nothing at all is an option too.

mikefamig

I'm not going to rush into rebuilding the control block or anything else, the car has been this way for years and runs great on the road. It is on jack stands right now so I can't test the ABC system but I will park it and wait for for it to droop as soon as I get it back on it's feet.

I posted that link as an FYI to the group.

Mike.

mikefamig

Being that my car is 14 years old I'm thinking that I should at least change the filter. The fluid looks nice and clean on a white rag and is full but I am concerned that the filter itself can begin to deteriorate at some point and it can't hurt to change it as long as I keep it clean. The car does not have a problem with the ABC.

It concerns me a little that there is a chance that changing the filter without a flush can dislodge some contaminant doing more harm than good. What do you guys think about that?

Mike.

EDIT - I said above that the ABC doesn't have a problem but it dies sag on one corner when parked. I'll test to see how long it takes to sag the next time I park it for long enough to see it happen. I just can't say from memory.

knowbenz

Where did you find the disconnect tool for $20? I would like to buy a few at that price.

You don't need to fully remove that rear assembly to change accumulator but I still want the $20 tool. I usually see it around $50

MarkCan

My local MB dealer. Just to rub it in I have to tell you that it actually was under $20 US. - $24.31can. and of course the friendly service with free cup of fresh coffee. Priceless 👌
Part number, 221-589-01-33-00 provided by Rudeney here.

BlownV8

If the car sags, there is something wrong. I can leave mine sitting for a month and there is no sag. Probably contamination in the valve block. Flush the ABC fluids and you may get lucky. If not, you need to rebuild or replace the valve block.

alk247

Where did you get your accumulators? Could you, provide a link, please. Unless it was from your friendly MB dealer. Thanks.

Alex.

bobterry99

In case you weren't aware, Alex, please know that your SDS can test your accumulators. Follow this menu path within the ABC and follow the instructions: Troubleshooting by means of complaints or symptoms > Handling characteristics > Vehicle damping too soft or spongy handling characteristics > Pressure change during pressure release.

If you need an accumulator I'll sell you a new one still in its unopened package which I got from Newparts.com a few weeks ago. I think $120 and I pay shipping to you is a fair price. Send me a PM if interested.

I also have one or two spare instrument cluster LCDs...

alk247

Thanks,

I will run this test. Then I'll know better if I need accumulator/dampener. As for the LCD, as I said, it cured itself with no human intervention. We'll see for how long it is going to behave. At this point it is all a moot point, since car is on the lift getting maintenance done. When finished, I am planning on posting lessons learned. And there is a lot of lessons. If I ever meet a guy, who wrote MB WIS .... Not to mention the guy, who designed some of the parts.

knowbenz

The 221 tool is wider than the 230 tool. Next one that comes through i'll give it a shot. I know the 230 tool won't work on 221 cars.

MarkCan

That’s an excellent point. I haven’t had the 230 tool in my hand, so I can’t comment but I see what you mean about the 221 tool being a touch wider.
I this case I’ll agree that in the less experience hand the 230 tool may be a better option.

blueduramax

I took a 9/16 open end wrench, ground it a bit thinner and filed the opening so it was a bit wider at the tips. It worked great on the hydraulic line coupler. Simply put it over the line and rocked it to one side neatly prying the coupler open.

mikefamig

How long should the car be able to sit with no change in the ride height?

Mike.

knowbenz

According to mercedes lowering after one week is normal. The majority stay up for far longer

mikefamig

Thanks, I'll keep an eye on it. Mine isn't driven often and it might have been a long time sitting when it did sag on me. The car handles great and I haven't had any other symptoms of a problem so I'm not concerned at this point.

Mike.

EDIT - After seeing the car sag I got into the habit of lowering the ABS when I park. I think that it is kinder to the system.

Listeriosis

does anyone know what LPC lower control and a big F means when you run "quick test" on DAS means?

bobterry99

A capital "F" shows a current fault in the controller, and, a lowercase "f" is a stored fault which is not currently active.

SLcharge

Mine stay up for month.

No sagging at all.

njbiker2008

Do you still have the lcd I have a sl500 2005 and mine look like **** how much do you want for them? T/K you