SLDOUG

Hello again all, remember my post “Problem that no one can identify”

Well after reading different comments and agreeing that the problem sure sounds like the pulsation damper, I had it replaced by an independent Mercedes specialist shop that I trust.

I am including some pictures with this post that can help Identify the problem. This is for a R231 2013 SL 550.

It’s difficult to pinpoint the sound because it starts at the output of the pump located front and center on the engine, travels down the pressure tubing inside the left front mudguard down to the valve block and finally to the Pulsation Damper.

It’s now my experience that the sound can start from either end making it hard to pinpoint is it the Damper or the pump. I was hopping for the Damper.

I don’t think that this is a DYI project unless you have specialized tools, look at the photos.

The first thing, my mechanic used was his High Teck diagnostic tablet to reduce the high hydraulic pressure down to zero without having to disconnect the hydraulic lines.

The first picture shows you the location of the Pulsation damper on a R231. Front left (Driver side) hidden behind the valve block and complicated to get to.

A special thanks to Mercedes for putting it in such a place that you must disconnect all high-pressure lines to get to it. The valve block and Damper are on rubber mounts, so it was easier to pull it out than loose time fiddling with it.

Once replaced, the mechanic used his tablet to increase the pressure back to normal, equalized the pressure on all for corners and told it to purge itself.

It was quite a sight to see the car jumping up and down on all 4 corners let to right, front to rear by itself for a few minutes to get the ABC system back to normal.

This whole operation took about 1 ˝ hours. Here in Canada, the EOM damper costs $ 375 and 1˝ hours of labor at $70/hour. Its close to a $500 repair. It took ˝ hour just to get to the Damper.

BUT NOW………..

The major screeching and grinding are almost gone but that darn intermittent writing hum vibrating into the steering column is still there. It’s much quieter but still there. Starts on idle 750 rpm, stops once I start to move up to 1000 rpm than stops and comes back loudest at 2000 rpm. The sound follows the RPM”s.








Previously, the Mercedes dealership had quoted a price of $3700 + labor to replace the pump. My research showed that in that price they were replacing the valve block and damper.

Has anyone ever heard of a defective valve block (Excluding the Damper) Are there any parts that can produce the sound I described? That valve block OEM is $1600 cdn and probably not required.

I put my stethoscope a stethoscope on the steel tubing just off the pump. I hear la loud clicking sound.

Is this normal?

Thanks to all posted their comments and best regards.

E55Greasemonkey

Wrong damper. You weren't reading or understanding last time, the damper you need to replace is the one attached to the pump above the V of the engine. It's a fairly simple job.

SLDOUG

Thanks for your input.



If you are correct, it could save me from replacing the pump.

All the info I found on this site plus the dealership’s inspection and part number 0003 2904 0080 is the pulsation Damper that I replaced 2 days ago and it’s located on the valve block.

I do not know what’s the name for what you are describing but as far as I know, there is no second pulsation damper.

This black ball on the pump must be called something else. It sure looks like a damper. Do you have the exact name or part number for it and if you are right does the pressure have to be reduced again because it looks like a 10-minute job.

ram_g

I fully agree with E55Greasemonkey. What you have had replaced is the front accumulator, not the pulsation damper. I gave you the relevant part number in my post #17 in your previous thread.

Edit, and yes, the pressure needs to be relieved in the system for it to be replaced, but I don’t think you necessarily need to do a “rodeo” (that’s what the sequence is called where the car strokes each shock one after the other).

steve sl550

Doug,

Lots of confusion for what should have been a simple fix.

Also early on discussion about "power steering pump/fluid change ect".....may have been caused by your mechanic familiar with the previous model SL (the R230) that preceded the R231 that you have that in fact had the ABC pump also being used for power steering but, as others have advised correctly the R231 uses an electric steering system (no pump or fluid).

Your mechanic should have given you a description of all components and the system and component operation.

Also IF there was no drop in fluid level in the ABC tank there was no need to change the front accumulator (only reason for replacing an accumulator is if the internal diaphragm leaks or ruptures; when that happens the fluid level will drop in the tank and a good mechanic will notice this and warning flags will also be seen on the dash ect)....... so.....what you and your mechanic diagnosed ....the noise from the pump output if found early enough (when first heard/felt) would only have need replacement of the pump pulsation damper BUT, if as I suspect the noise went on and worsened it is possible that not replacing the pulsation damper led to a pump issue and the pump may now in fact be damaged......I would still replace the pump pulsation damper first and see if the MB dealer will credit you if the pump needs replacement as the pump comes with the pulsation damper.

You rightly located the noise on the pump output line but followed the noise to the front accumulator rather than staying focused on the pump output pulsation damper. Noise will always transmit through metal and no surprise it could be heard at the end of the metal output line at the front accumulator but, unless there was a drop in fluid level in the ABC supply tank should not have been suspect that the accumulator failed. Maybe reason for some improvement after replacement of the front accumulator due to the accumulator maybe partly leaking internally loosing some of nitrogen charge but, again original problem seems centered on the pump pulsation damper.

BTW....really noisy pumps are usually caused by running dry (if there had been a leak and loss of fluid from a failed strut or ruptured hydraulic hose ect so...if you had no fluid loss maybe your pump is OK./....Was there ever any fluid loss that would let the pump run dry or without sufficient fluid for internal lubrication???

Correct names and understanding of operation are important:
The ABC system is a hydraulic closed system that operates by means of high pressure pump output smoothed from pulsations by the "pulsation damper" (really just an accumulator but ,used to smooth out the demands of the system on the pump as the struts operate against pump output). The pump output fills all lines and the struts with hydraulic fluid under high pressure against the front and rear accumulators (the accumulators are spheres with a rubber diaphragm in the center hydraulic fluid from pump output on one side and nitrogen on the other side......the nitrogen acts like a cushion as the struts move up allowing the struts to discharge or accept hydraulic fluid. The valve blocks (F & R) take input from many sensors and meter out fluid under pressure to or from the struts as needed to maintain correct vehicle position.

See attached for some more info and note suggestion to replace the pump pulsation damper when symptoms like yours identified:

https://www.import-car.com/mercedes-...spension-tips/

We with ABC on the R231 are interested in your responses as MB improved much of the original RR230 ABC system.

PS: I have been told that the complete valve block assembly can be pulled out for accumulator replacement by just removing the brackets holding the assembly and the hoses and then all comes out w/o removing the hoses ?????

SLDOUG

Hi E55Greasemonk
Ever heard of Murphy's law?

Yes, I know that you gave me some advice and picture last July and the link you supplied led me https://m.blog.naver.com/ykim2500/221713983144 to a Korean site in Korean language and on a different model. Since I could not get solid confirmation from that site or part number, I kept on investigating.
I also got help from Ramg who was kind enough to supply the part number for the pump damper https://www.mboemparts.com/oem-parts...r-000466040087 It was the wrong part and did not compatible 2013 SL 550.

This repair went off track when I asked the dealership for the part number of the pulsation damper so I could order it myself, and he quoted the wrong one. I asked my independent to install it. They trusted me for the part number, and they installed it where it was supposed to go, not their fault.
So now, I am still trying to find the correct part number for this pump damper myself, don’t trust dealership anymore.

Best regards to all
SLDoug

SLDOUG

Hi Steve, thanks for your reply.
Yes,I agree with you, lots of confusion for a simple fix.
I just sent the following answer to E55Greasemonkey. It should explain why I am still trying to find the correct part.
Dealership or independant shop have not seen this problem before and were confused because there was no fault codes, oil leaks or dirty pump oil, oil level so nobody wanted to commit themselves for replacing the wrong part.Hi E55Greasemonk
Ever heard of Murphy's law?

Yes, I know that you gave me some advice and picture last July and the link you supplied led me https://m.blog.naver.com/ykim2500/221713983144 to a Korean site in Korean language and on a different model. Since I could not get solid confirmation from that site or part number, I kept on investigating.
I also got help from Ramg who was kind enough to supply the part number for the pump damper https://www.mboemparts.com/oem-parts...r-000466040087 It was the wrong part and did not compatible 2013 SL 550.

This repair went off track when I asked the dealership for the part number of the pulsation damper so I could order it myself, and he quoted the wrong one. I asked my independent to install it. They trusted me for the part number, and they installed it where it was supposed to go, not their fault.
So now, I am still trying to find the correct part number for this pump damper myself, don’t trust dealership anymore.

Best regards to all
SLDoug

ram_g

Trust me, it IS the right part. Did you actually acquire the part and it didn’t fit - a rhetorical question, because that couldn’t have been the case. I know the MB parts catalog does not list the R231 as a compatible model, but that catalog has plenty of errors and omissions relative to the R231. My understanding is that the part is indeed correctly referenced in the Xentry repair system that the MB mechanics use.

I am not at home currently but I could take a picture and post my invoice from when I had my pulsation damper changed, and it is the same part number.

SLDOUG

Hello ramg,
As you have read so far, I just spent $500 for a repair that was not needed only because I got the wrong info.
You can understand that I have to go on confirmed facts. I cannot afford buying another part that they lists as incompatible.
Best Regards

E55Greasemonkey

PM me your VIN so I can find the correct part.

SLDOUG

I just called my Dealership for the part number and was told 221 327 0215 $ 373 +30 minutes.
Now I have to make sure that they have the right part this time as I already lost $500 in this adventure.
VIN is WDDJK7DA2DF003419
I appreciate your effort to help me
SLDoug

ram_g

I honestly feel like this is the same part you’ve already replaced - or maybe the rear accumulator. But not the pulsation damper.

SLDOUG

You are right, after checking my old invoices this d.... dealer almost screwed me again even after clearly explaining the I am talking
about the one directly on the pump. I also went online with this part number and they ID it as a pulsation damper but nothing clearer.
This is getting harder and harder to get the correct information.
Thanks for warning me, I will keep on looking as this part is almost impossible to find on the Web. There are tons of info for R230 and older
but not much on my R231 M278.
Regards SLDoug

ram_g

You already have the correct information, Doug, but you don’t want to take it. Attached the invoice from my successful repair of the same noise symptoms. Same part number as I’ve posted before. Yes this is for a SL63 with the M157 engine but I can’t imagine the SL550 / M278 uses a different part. (The parts catalog didn’t list the SL63 either.)

Edit: Invoice now re-posted with personal information redacted.

E55Greasemonkey

This is the correct part number for your VIN. 000 466 03 10 . Check this part number with a dealership to make sure it doesn't supercede to a different one.

E55Greasemonkey

This website shows an updated part number of

000466040087

https://www.mboemparts.com/oem-parts...AtNDY2LTAzLTEw

SLDOUG

Sorry ram g,
it's not that I do not want to take your advice but the Web site from whom you bought it from says it will not fit.
I am checking this out and will get back to you

SLDOUG

OK, right now I have a list of 7 different part numbers for this damper all the

SLDOUG

OK, right now I have a list of 7 different part numbers for this damper. 000 466 03 10, 00 10, 0310 80 466 04 00 and 000 466 04 00 80.
All of them are replaced with the description "Power steering pump insulator Part # 000 455 04 00 87 and as per their Web site, it would not be not compatible with my car.
I sent a message to MBEOMparts.com to clarify.
Will let you know when I have more info.

ram_g

I did not buy it from them, or anyone else. My mechanic replaced it correctly, and the invoice lists the same part number. I have no idea where he sourced the part from.

When greasemonkey checked out your VIN and is listing the exact same part number (see his post about superseded part numbers) I have no idea why you’re being so hesitant.

“You can take a horse to water but you can’t make him drink”

SLDOUG

Hey ramg,
I am not hesitant, I simply will not buy a part that the seller says it is not compatible with my car as per their Web site MBEOMPARTS.COM
So if you want to guarantee a refund if it does not fit let me know otherwise then drop your quotations

Wolfman

Hesitancy is one thing but members helping you only need to do this to a point. Both E55greasemonkey and ram_g already listed the same part number, which appears to be the latest version. Nobody needs to guarantee anything here; otherwise I suggest to do your own research or have a dealer fix it for you.

ram_g

I have now (re)posted my invoice in post #14 above, with part number circled and description underlined.

I am done with this thread. Good luck.

SLDOUG

Thanks for your help, I am still waiting for conformation from the seller
Best Regards
SLDoug

steve sl550

SLDOUG

Did you keep or can you get back the "damper" actually the front ACCUMULATOR that was replaced.

I'd like to know if it really failed and the way to tell is to look into the open threaded end and see how far into the sphere you can insert a screwdriver.

If the accumulator is good the internal diaphragm will be close to the open end....if the nitrogen charge has leaked through the diaphragm (failure mode) the screwdriver will travel well into the sphere.

See here link that will show you how to see if the removed accumulator was in fact bad or was it good:


Let us know what you find

Again....we all suspect your issue was the "pulsation damper" at rear of the ABC pump (hope you didn't end up with damaged pump as well as you continued to run when the noise was heard but, usually if fluid is not lost just replacing the pulsation damper will fix the issue

Think we would all like to know the actual condition of the accumulator that was replaced in your picture above as we with the newer R231's are trying to determine how long the accumulators will last as I suspect they are a "wear" item that should be replaced at some point in the cars life....maybe at 75K miles?? Trying to collect field info so we best know when to put these on a PM list.

So.....
1)Let us know the mileage on your car
2)LET US KNOW WHAT THE CONDITION OF The REMOVED ACCUMULATOR IS....FAILED OR GOOD PER MY TEST AND PER The LINK