bobterry99

The dipstick should show a lower level of fluid with the engine running. If you examine your dipstick you will see two ranges for proper fluid level when taking a measurement: one range is for when the engine is running, the other is for with the engine off.

cal1

Sorry, stupid post on my part When the engine is off, the fluid is at the appropriate level. When the engine is on. The fluid level is lower than the appropriate "on" position.

bobterry99

It may be completely implausible, but in theory if an accumulator were to lose some of its nitrogen gas I suppose the difference in fluid volume it holds between pressurized and unpressurized states would increase.

I would run the Star Diagnosis routine which I believe to be test of the accumulators. Within the ABC menu of my 2008-vintage software I go to Troubleshooting by means of complaints or symptoms > Handling characteristics > Vehicle damping too soft or spongy handling characteristics > Pressure change during pressure release.

cal1

^ thanks bobterry. Whoa! DAS is like a giant nearly infinite decision tree. Props to you for finding that very helpful path. I just used DAS simulator to find it. I like to practice a routine in sim before going out to the car and plugging in. I am never sure when and how many amps I should supply to the main battery while running DAS.

On a side note, I am beginning to wonder if I had an odd one off situation with ABC that led to the fluid burp. First off, I suspect the fluid spill on the ground looks much worse than it really was. Shortly after the spill, I noticed the right front tire sag. It has not done this since. I failed to mention to anyone that i have the car lowered about 1.5 inches with a lowering module. Being lower than normal makes me think more fluid would flow back to the reservoir with engine off.

I drove the car quite a bit this weekend. It is running sweet. No codes, no nothing right now. I will run the routine mentioned above later this week and see what happens. One thing I have noticed lately. I seem to be getting "MFD lock". I am constantly glancing down at the MFD for warnings. I doesn't make the driving as enjoyable.

bobterry99

I have never had the need to connect a tender to the battery while using SDS -- in my experience the battery voltage has never fallen significantly. If you were to run your battery down, the consequence would be no worse than simply suffering the "Consumers Offline" condition for a brief time once the engine is started.

cal1

I have been enjoying the car trouble free for the last two weeks or so. After doing the diagnosis I listed in earlier posts, I started driving the car. No codes on the MFD, no droops and no drips, the car drove beautifully. Even got the rare opportunity to have a run with a vette out on the wide open country roads. He lost.

This morning, I noticed no drooping on any wheel. I started to car and got the white "ABC" code. wasn't too concerned. Ran the car to the store without any trouble. When I came out of the store, I got the red "ABC" warning. The car was not low at all. I checked fluid only to notice a fresh burp. The fluid level was maybe 1/4 inch below the engine on level. I drove the Tuna boat home carefully. When I did a restart and kicked into gear, no codes at all.

At this point I will hook up my DAS and pull faults.

cal1

I have been doing a ton of research on methods to flush ABC fluid. Since I'm a novice, I tend to overthink all of this stuff. For you masters, disregard the post, or you might find something you like about this. Many may have already seen it so apologies for reposting if that is the case.

This video demonstrates the method I intend to use to flush ABC:


The tool can be purchased here: http://www.agatools.com/tool/mercedes-abc-flush/tool

It is $119.00. Well worth the price to me.

perren75

Hi,

I've flushed my abc on my 2003 SL55AMG and I don't think the tool in the video would work as the filter don't go into the bottom of the reservoir.. The return line is on top and oil flows down into filter - not up. It's very easy to remove the return line and extend it so its long enough to go down in a large bucket.. Hose, two clamps and e hose to hose connector was like 10$ if I remember correctly.

I've had similar problems like yours. I'll try to write something later today about my issues and is how I solved them...

Edit: they actually states this in the last picture - if it looks like the right picture simply unhook the hose..

Brgds
Pelle

perren75

Ok - after a "hard" saturday iīm finally down in tempo and able to have a moment in my homeoffice to be able to write a reply as earlier promised

Looking at the your pictures - where the "puddle" of oil was - I would strogly suggest lifting front left of the car, remove the wheel and then the plastics in the whell-arch (correct word? not sure but i think you get it). There are several plastic nuts, a bolt "in the top" and you will also need to remove a few bolts of the "under car covers" to reveal a few more plastic nuts. The "covers" underneath the car are fastened above each other making it impossible to remove them one by one - well not impossible - but they are kept in place "together"...

Hard to translate all the info I gathered so far and please keep in mind iīm not a "native english language person" that just does the best i can so far

Anyways... I suppose that you might have a leak in the main pressure line going from the pump to the first "block" of the ABC suspension. This line starts from the pump - metal pipe - goes down under the AC pump, straight forward to the front of the engine, then turns right (to passenger side) just in front of the engine. Just right of the engine it goes from steel-pipe to a hose, then a bit of pipe again, then hose and then pipe and then there is a "pipe-coupling" just where it leaves then engineroom and comes out to the wheel-arch.. Then a short piece of pipe and then some more hose before it connects to the first block that consist of a pulsation dampener, the pressure sensor etc... This part of the pressure line - the hose just below the "block" - was "sweating" in my car and would probably have ruptured any time soon. The pressure would normally be letīs say 150-200 bar here as this is "before" any pressure regulation is done as far at I can see.. After this "block" it divides into fron and rear pressure lines..

In this "block" there is a pulsation damperer. Very easy to change, and while looking and "fiddling" with this part you might as well change it... The block is held in place by 2pcs 10mm nuts.. I also removed the hoses attached to the block to have a good visual inspection of the blev etc. It will go bad sooner or later... And while having the plastic covers removed from the front left wheel - you might as well replace the front axel accumulator as well. These two maintenance replacements are like 1h job total.. Maby less.. Parts are quite cheap and I think itīs good investment for the future if you plan to keep the car..

Inspect all hoses and if they look "wet" - try to replace them. I only had one that was weeping oil (the one in the pressure line)... All the others looked perfect...

On the 13th of june i got the "ABC Visit workshop" message after having a few "drive carefully" last year. I did a flush one year ago with 10l of pentosine and new filter - car didnīt drop before and has not after. Had the car i my small garage on jackstands for almost two month (did 3 weeks of sailing, building a new sun-deck etc during that period) and at the moment itīs up and running again. Put in a new (well not new, but rebuilt pump, 2 main accumulators, pulsation dampener and return accumulator and also did a "remake" of the main pressure line). The car is much more "firm" and handling better than before. The new high-pressure line is most hose instead of the old "pipe-hose-pipe-hose-pipe-hose" type in heat resistant sleeve that can not be inspected - thought Iīd might as well get a new "construction" when redoing it. Maby a total of 15-20 hours for replacing pump, main pressure line, total of four accumulators, cleaning etc.. Feels like a new car now...

The day i got my "red" ABC message i noticed quite a bit of air-bubbles in the reservoir. I drove the car home - still getting these messages after restarting, letting it rest a few hours and restarting again. The day after i got it running without warnings and were able to do a "rodeo" (the dynamic test in star/wis/das). My pressure was ~180 at idle with no movement.. below 100 when doing rodeo and down to 120-130 when just raising the car by "two quick hits of the raise buttom". Now - with rebuilt pump - i stays above 150bar when i did at 1min rodeo test... The only "air bleed" i performed after having changed the pump, the accuīs and the pressure hose/line was raising and lowering the chassi with the "raise button" 15-20 times,... And after that a short rodeo test (max 2mins). I think that it was a rupture in one of the accumulators... Not sure which one though - the two main seems "OK" with the "screwdriver" test - but that doesnīt tell the nitrogen pressure of them,.. And the two other canīt really be checked that way i think. But replacing them seems like a cheap thing compared to having debris in the whole system..

Car runs great - chassi is perfect now and the pentosine is clear green but I have like 8 liters left so iīm thinking of a flush in a couple of weeks.. Better safe than sorry...

If you have any questions - please let me know and iīll try to answer. Have done several hours of reading, rebuilding, inspecting etc so by know iīm starting to feel a bit "safer" on the ABC system.

Best regards,
Pelle

cal1

Thanks perren for the write up. I notice quite a bit of air-bubbles in my reservoir. Do you think it could be gas (nitrogen) from a blown accumulator?

perren75

I recon that it definitely could be nitrogen gas coming from one of the accumulators. Most threads I've read is about totally ruptured ones but I've come to think that they might just release part of the nitrogen when rupturing.

As my accumulators didn't show any evidential faults but with the car handling much better now I think that some of the nitrogen can leak into the system but it still seems to work as it should...

The pump could be the culprit but I would start with changing the accumulators and see how that turns out...