I don't know if you will get this message now that you have sold your car. I wanted to ask you a few questions about your experience in changing out the 2 accumulators. I have an identical 2005 SL500 and decided that changing the two large accumulators is reasonable preventative maintenance. My car has 96K miles. I have not had any red warnings but I don't believe waiting around for one to occur is the way to go, I bought the car a few months ago and thought I could relate to your experiences as a new owner.

I am planning on doing mine this week.From the videos I have seen, the hardest part (for me at least) is getting the car jack up and taking the wheels off.

 

Have you started the work yet? I found the videos done by D Wray's Garage. Always room for improvement but he does give a pretty clear idea of what needs to be done to change out two main accumulators.

As far as jacking up the car, I found a video where the universal housing was used in the rear with a low profile jack. That looked reasonable. On the same video a single jack point was used in the front as well but I couldn't see where the pick point was. I am going to ask the guy who made the video.

 

Doing mine tomorrow.

 

The rear jack point is under the diff.

The front jack point is where the two cross braces meet the subframe, If you can't see the 'puck' where the jack meets, it's probably missing (like mine). I ordered a newie; it's inexpensive.

 

I found a video on youtube -- How to jack up a Mercedes Benz. Lots of practical advice. I'll have to try to find the front jack point. The 4 side rubber pads on my car exist. I'll have to get some hockey pucks as he suggests.

 

Jacking up the car safely is a necessary, basic piece of knowledge, for sure!

The replacement front jack point just arrived. The 'pucks' mentioned are the nicknames for the four round jack points; two on each side of the car.

Replacing the accumulators is a rite of passage for many here, and a pretty easy straightforward job. You need a 17 mm flare wrench, not 11mm as D Wray says at the start of his vid. Also at 7.55 you see him loosening the nut on the hydraulic pipe with a standard 17 mm open end spanner. Slack, man! That's what the flare nut spanner is are for; so you don't damage the nut.

 

17 mm flare wrench

Thanks for sending the photo of the front jack point. I will check my car to see if I need to order one.
I have the 4 round rubber jack points on the car. In the video the guy mounts actual hockey pucks to the top of his jack stands to mate with these rubber round jack points on his car.
How many accumulators did you replace? On the 2005 R230, there are 4 that could be replaced. I will for sure replace the 2 large ones but don't know about the other 2. If you did change all 4, are there references you could give me so I can see what is involved? What about the difficulty of doing the 2 smaller accumulators compared to the larger ones?

 

The four side jack points are a bit susceptible to damage which is probably why he protects them.

There are four accumulators and with what I know now, I would just jump in and replace them all, regardless. They all fail over time it seems.

If the pulsation dampener fails you'll feel a low frequency vibration that varies with the revs, but be aware that if your engine mounts are shot that can give a similar feel through the seats, but the failed PD is a very obvious grinding vibration sound.

The front pressure accumulator is easily accessed via the panel under the bumper.
The rear pressure accumulator and return accumulator are accessed by sliding out the whole assembly like he does in the video. Careful not to damage or kink the soft hoses with the assembly hanging out.

Some people don't worry about changing the return accumulator, but it wouldn't be there if it wasn't needed, would it? However that's the only one that does not appear to be available as an after market unit, and it was quite expensive from MB as a genuine part.

You will luxuriate in the magic-carpet ride with fresh accumulators. It's something to behold.

 

ABC2 eliminated the return accumulator and moved the PD to the pump, so maybe the revised fluid paths no longer required the return accumulator. I would replace it while the block is out, but that's just me.

Rotors and pads are one of the easiest jobs on the R230. You can just disconnect the batteries then pump the pedal 20 times to release the pressure in the ABS accumulator (a procedure from other ABS equipped cars I've worked on - I don't know if it applies to the SBC system or not though). I think it does though, because if you pump the pedal a few times you'll hear the pump running to recharge the accumulator.

As long as you don't wake up the car you'll be fine. Think of the open caliper like a live power point and NEVER put your fingers in there - there is no reason to anyway. Crack the bleeder nipple to spread the pads.

To fit my front puck I will jack up the car from the sides and remove the underbody panelling then I think it should be obvious where it clips on.

Good luck. It's actually a pretty easy car to work on, all things considered.

 

I wanted to comment that I found the space where front puck (take-up device) is supposed to go. I don't think the underbody paneling needs to be removed. On my car in the space there is now a large bolt and some other piece that I assume was part of the original part 230 628 0149. I'm going to have to use 2 jacks to lift the car to get proper access. I only have one jack and that bolt requires a T45 or something similar to remove it. I couldn't get to it properly and I'm not sure the T45 is the correct tool.

 

Welcome to the forum @Billtim - please take a moment to read the information on the links below. It explains how to use the forums and update your user profile so that your car's details and your location appear on each post below your avatar. This is good information for others to know when trying to help. It also has good information about how the forums are organized and how to use the search feature:

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Complete your profile.

I moved your question to its own thread so as not to clutter up the other poster's "for sale" thread and to give better visibility to your question.

 

Bill

I'll get out to mine pretty soon and have a look. It came from the parts diagram at MB so I think it's the right part. I wondered if there were bits missing too.

To get the car up on axle stands and remove the under-engine panel, you can just put the jack where the two cross braces meet; that's what I've been doing for years. Or use the 'pucks' on the side of the car for your floor jack, but since that's where the axle stands go, the bolt idea might work. Personally I'd get a solid piece of box section steel to slide into those tubes rather than a bolt, which doesn't sound very secure.

 

Hi Tom,
I've been working on the 2 main accumulator exchanges. The front one was exchanged with no problem. It turned out to be still good. I consider it lucky I was able to exchange it without a problem after 96K miles. I'm intimidated by the rear main accumulator exchange. You told me to be careful with the hydraulic lines. There is a bracket on the bottom right the holds three hard lines coming from the accumulator area. If the bracket was opened it would allow for less strain on the hoses when I'm folding out the accumulator to exchange it. It also looks very difficult to open. If you know the bracket I'm talking about do you have an opinion about opening it to allow those hard lines to move while I'm making the exchange? Any comment would be appreciated.

Bill

 

I like the bolts. They are a high-strength 3/4' special bolts 10 " long. I've tried them- they work.
On the center jack point, I found a ledge for those hooks to grab onto, then the piece just swivels up and snaps in - or is supposed to. Mine did not want to stay. I'll have to adjust it. Suddenly I got the idea anyway.

 

You can just see it in the bottom right hand side of the photo:



That's it. Undo the nut, slip the bracket off, then the rubber grommet, then the whole assembly slides back and out, allowing access to the valve block and accumulators. At this point be careful not to stress any of the soft hoses but there's enough flex in them to allow access to the accumulators.

There's a nut right at the top too which you have to take off.

 

Ok so the bracket needs to be loosened. I have about 4 different ways I'm being told how to get access to the accumulator. Do you have a reference video or writeup that you think gives the clearest way to do this job? I know about the top nut, it's the rest of the process that I don't understand.

 

On my 2003 sl500 there is also a small accumulator in that pictured rear assembly. I replaced all 4 accumulators.

 

Don't overthink this; it's all really easy. Put aside any erroneous advice you may have read and remove this nut:

Clip off the clamp, wiggle the grommet out, then the entire valve block assembly with accumulators will slide back, then out of its little track on the bottom, then sort of hang there, supported by the flexible hoses.

That's when you have to be careful not to let it drop.

 

Yes, that's the trick.

The bolt off at the top, then the clamp on the lines off (use a bit of silicone spray to help wiggle the grommet out and back in again later) then slide the whole thing back on its track. You'll laugh at how easy it is when you've got it out,

 

I wanted to tell you that things progressed today so that I feel confident that I'll be able to finish the job of installing the main rear accumulator. I was able to get the lower right side bracket off and loosened the grommet some. I also loosened the upper outside bolt on the assembly and pulled the entire assembly forward about an inch. I stopped there because I have back problems and need to wait for my neighborhood mechanic assistant who is helping me. We are adding new brakes and replacing the 2 main accumulators. I was a little worried when I saw that track and some of the fine sand and grit that had accumulated there over the years. I sprayed the area with lubricant and told myself that a much younger man will be able to pull the assembly the remainder of the way with some up-and-down, side-to-side motion thrown in to help things along. The grommet will come out with some effort. I want him to see it in its current state so he can put it back together.

While looking around for leak stains on any of the hoses, and at the condition of the struts, the only thing I see is that the dust covers have split on all four struts. Nothing leaking.

 

Do you remember if you backed the assembly completely off the track or just slid it out some when you changed the accumulator? I realize the job would be easier if the assembly was completely off the track but I think my assistant can manage the swap where it is now. I've pulled it back about 2 inches. Also still having trouble completely removing that grommet. As it is now two tubes are free of the grommet. The piping feels really rigid and mostly stationary. Most of the movement is coming from the hoses. I don't want to move them around any more than I need to.

 

With the clamp on the grommet removed, then by lifting the lines slightly, the whole assembly will slide all the way backwards out of its track, then once it's out, slightly up and forward again, where it can rest while you work on it.

I don't think it's necessary to remove that grommet completely but it may help you gain maneuverability. Use silicon spray to get it in and out.

 

I got the second accumulator out of the car today and am surprised that both appear to still be in working order. I can't tell from the part # the date of manufacture. 96000 miles on the car. They have the Mercedes logo. What I find surprising is the number of these for sale on ebay for close to $95 US each! Who would buy one of these used with no idea how old it is? Worse yet actually install it! For sure as soon as you do that the diaphragm will fail!
I don't think it is a waste of time to replace these now as preventative maintenance. I know you have the same opinion.

 

Is there a torque spec for the main accumulator bolt? I have the new rear accumulator mounted and have hand-tightened the bolt waiting for the mechanic to come back this weekend to tighten the bolt and help me close up the assembly. Difficult to use a torque wrench in that area but I thought I should ask.

 

AFAIK there are no flare nut attachments for a torque wrench, because the extra leverage will give a false reading.

Perhaps MB have a special tool, and a spec. I settled on 'pretty tight then a little bit more'.

Don't overtighten it. Feel the tightness on the front one for comparison.

It doesn't have to be too tight to seal. Just feel it, so you don't strip it.

 

Yes there are . You need a set of Flare Nut Crows foot attachments. I just got a set off of Amazon.

 

You do need these to work on the valve blocks (at least the 17 mm one), but fitting them to a torque wrench will give you a false reading, due to the extra leverage caused by the offset between the two drives.

Put a wheel stud in a vise and test the difference between a 17 mm socket directly-connected to the torque wrench and the offset crow's foot and you'll feel the difference.

 

You do need these to work on the valve blocks (at least the 17 mm one), but fitting them to a torque wrench will give you a false reading, due to the extra leverage caused by the offset between the two drives.

Put a wheel stud in a vise and test the difference between a 17 mm socket directly-connected to the torque wrench and the offset crow's foot and you'll feel the difference.

Not true. There are formulas that are used to calculate torque when using different extensions and attachments.

Calculating torque values

 

Handy to know.

But yes true that reading the the torque from a wrench fitted with an offset attachment, without recalculating, will be wrong. In any case it's easy to feel it with the lines to the VB. They don't have to be too tight to seal, and extra care should always be used when working with aluminium.