Was at the dealership yesterday for some maintenance and they claim upon inspection the right front mbc strut has a drop of oil coming off the seal and the right rear shows slight seepage. The hydraulic reservoir was down a very slight amount so I had them top it off. Car has 81k miles on it and I do use the curve mode just all the time which probably puts more wear on the mbc struts. The car is not leaning to one side yet and no suspension messages and no drops of oil under the car where it’s parked in my inside garage in Florida. The car recently has sat parked for 6 months in the garage but to my surprise when I just returned back a week ago the car was at its normal parked ride height not dipping on any corner. My experience with Airmatic has been after storing such a time the air springs are always sagging but fill up after the car is started. Dealer tells me these struts are wear items and last 50 to 100 k miles. I disagree and think this system was over engineered by Benz from everything I know and struts should last upwards of 200k miles. Dealer wants to replace all 4 struts at a cost of 16k. I dunno I kinda smell something fishy here. Back in the day I remember many mechanics would spray some oil on shocks and struts to get work and make a large profit. I guess what I’ll do is wipe them down and keep an eye on them. I just hope they didn’t drive a screw driver into the seal to damage it or anything? Driven 20 miles since the service so far and all seems fine. Thoughts? I never did get around to changing the fluid so it’s 8 years old now and 81k miles.

 

its plausible. My S class went through its air struts within 100k, they were still "working" but the ride was massively improved just replacing them at the first sign of moisture. Get a second opinion. Also 16k sounds brutal, unless you are tied down to the dealer please seek an indy out. It's very possibly close to half that, and I would just replace the rears first.

Its very very pressurized, a leak would cause a fairly rapid loss in fluid for the 10+ years I have with hydraulic MB suspensions going back to the 90's and the silly hydraulic convertible tops from the R129's.

I recall the struts for these being like $1700 a corner? I'm probably wrong and it might be for the airmatic though. Labor + a couple hundred in fluid is $185 at any decent shop. But no, no strut lasts 200k, they are wear items and the harder you use them the sooner they go. The S Class burns through parts much faster than the E and C models. MBC is Rolls Royce level technology its GOING to be expensive

 

Find independent mercedes shop for more realistic price. As far as how long they last AI says:

Mercedes-Benz Magic Body Control (MBC) struts typically last between 50,000 and 100,000 miles. However, their actual lifespan is highly dependent on driving conditions and vehicle maintenance.
Factors Affecting Lifespan

• Driving Conditions: Frequent driving on rough, uneven roads with potholes and speed bumps accelerates wear and tear.
• Vehicle Load: Consistently carrying heavy loads or towing puts extra stress on the suspension system, which can shorten the lifespan of the struts.
• Maintenance Habits: Regular inspections can help identify issues early. A qualified technician should inspect the suspension system every 12,000 miles or once a year.

Signs of Worn MBC Struts
MBC struts should be replaced immediately if they are damaged or leaking fluid. Other common indicators that the struts need replacement include:

• A noticeably bumpy or uncomfortable ride.
• Poor handling and instability, such as excessive body roll during turns or a feeling of looseness.
• The vehicle's nose dipping excessively during hard braking ("nose-dive").
• Uneven or "cupped" tire wear, caused by inconsistent contact with the road.
• Unusual clunking or squeaking noises from the suspension.

Performance tends to degrade gradually over time, so a noticeable difference in ride quality may be hard to spot until the problem becomes significant. It is recommended to have them inspected by a professional technician once the vehicle reaches the 50,000-mile mark.

 

OP my 221 S-65 with ABC had a L/F strut that was always wet; would drip when on the hoist at full droop. ABC is supporting the weight of the car. Dampening of body motions is done by the shock; built into the strut. The struts can leak ABC fluid for years. When body motions get sloppy due to a failing shock it is time.

My 222 S-65 also has a front strut that is wet. 150,000 miles.

Replace all four? Nope! Wipe the oil off every time it is on a hoist.

Change the MBC oil and fluid filter. Easy to do.

 

Speed bumps have take one of my shocks at 68K miles.

 

Thanks for the good info everyone. Until I see hydraulic fluid on the garage floor and the right front dipping down after being left parked I’m not gonna worry about it. Makes sense that being put on a lift when the strut is fully extended might cause a little seepage especially as they get older. The car still ride perfect no strange noises or any other symptoms. Of the car can sit for six months and no struts droop they can’t be too bad. I’ve driven the car over a lot of rough roads in Rhode Island and I use to speed up for speed bumps cause I thought it was cool you couldn’t even feel them at least during daylight hours. I do see that eBay lists some aftermarket mbc struts with a 2 year warranty for my 2018 to 2021 s560 it says. They are only $408 each so that’s less than 1700 in parts and maybe get someone to install them for 500 bucks. I could live with 2200 for the job. 16 grand at the dealer is just plain nuts.

 

Flush the hydraulic system with new oil and 3% omega 917 and it is quite possible to stop playing and change the filter There is a special tool from agatools.com

 

Interesting discussion ... my LF MBC strut has some seepage, but not enough to drip and I'm not seeing the fluid level in the reservoir change, so perhaps no action needed..

My understanding is an MBC strut contains a steel spring with a hydraulically-operated movable top spring perch. You can feel the spring under there by pressing on the plastic cover. I am not sure how damping occurs exactly, one would think the same mechanism that allows the spring perch to move dynamically could also provide damping, but there might be separate dampener in there too. In which case, the separate dampener could wear just like a conventional shock absorber and then require the whole strut to be changed.

Has anyone changed an MBC strut and felt an improvement in ride and control afterwards?

 

I found these on eBay that looks like they should fit says 2018-2021 s560. https://www.ebay.com/itm/14633572722...Bk9SR8KU-K3OZg

Much less money than oem and says two year warranty. Could have an independent shop replace the fronts for now if necessary. I guess though probably a little seepage is fairly normal as these get older especially after the cars been sitting around for the past 6 months and then up and down on the lift a few times. Strange that the dealer who recommended changing out all 4 struts didn’t even think of checking the hydraulic fluid level in the reservoir at least until I mentioned it. That’s kinda a red flag right there.

 

Do yourself a favor and find a good independent MB specialist!

 

That’s what I was going to do is go to an independent shop there’s one in Englewood the next town over. When the leakage gets bad enough I’ll have them replace the struts with the aftermarket ones and flush out the system and refill with new fluid.

 

Did the fluid and filter change today. Took a real long time getting the aftermarket Amazon filter in as it was just slightly too long and I had to file down one plastic end of it some to get the mount to twist and click in while being extra careful not to get any plastic particles inside the filter. And then cleaned everything up really well.

I then removed most of the fluid from the reservoir tank using the electric pump. Then I filled with the same amount (1 liter) with the funnel then put back in the filter assembly and checked the level and took the car out for a work in drive turning up and down the suspension level control and put in curve mode and drove some winding roads. All is good I swear the suspension seems smoother now. In about a month at I’ll pump out the fluid in the reservoir again through the dipstick tube without removing the new filter and refill with another fresh liter.

Not ideal but chances are at over 81k miles an accumulator is gonna go anyhow and gonna get another fluid refill when the fluid leaks out from that. I’d still like to know how to replace the accumulators. I think there is one at each Strut?

If nothing else I could advise the shop wherever I get stranded how to do it and the part number. If they are all the same it might make sense to carry a spare accumulator in the trunk? Trying to stay ahead of things with this higher mileage 2018 S560 Benz.

 

The nitrogen bomb that threads into the pump will fail most often. I’m averaging every 30,000 miles. When it fails it will deliver oil from the reservoir to the left front of the car. Everything under it will be a mess. The other (much larger) nitrogen bombs last a long time. 152,000 so far in my car.

 

Are there any symptoms to a failing accumulator before a visible leak? You mention common failure mode being to 'deliver oil from the reservoir to the left front' ... does that cause any noticeable change in how the left front feels/behaves?

Oh, and Happy Turkey Day!

 

I’ve been lucky my car has been 81500 miles and I’ve never had one of those go yet. The fluid and filter change I just did a couple days ago was the first hopefully it wasn’t counter productive.

 

When the diaphragm fails in an accumulator all the nitrogen (under high pressure) is introduced to the (closed) hydraulic circuit. As the gas finds its way out via the reservoir it pushes all the hydraulic fluid out to make way for the gas to exit. When started you will hear the pump growl; often followed with a MBC warning in the cluster. Turn it off immediately and check fluid level. You may notice a trail of breadcrumbs emanating from the left front corner. A mess.

Happy Thanksgiving to all!

 

If an accumulator fails, in addition to causing the MBC pump to lose its prime, you may also notice the fluid level is too low when the car is shut off. This is because the oil is stuck in the accumulator and isn't being returned to the tank from the gas pressure in the accumulators. On my W220, the ABC pump would not prime after an accumulator failure, and I failed to diagnose the issue properly and replaced the pump. Because of this, I replace the accumulators after 10 years/100K miles (I just replaced the front and rear accumulators on the W222 this week). The low pressure return accumulator will need to be changed eventually, but I don't remember it causing big issues when it let go on the W220 (just occasional pressure warnings while driving over dips in the road). The pulsation damper on my W220 lasted the life of my ownership (up to 23 years, 190K miles).

 

'Pulsation dampener' for your 220 a very different design.

Where is the 'low pressure accumulator' hidden for the 222? Poking around I find the Accumulator on the front valve body, another that pokes into the trunk and the little one on the ABC pump.

I have the pair of them for front and rear (same as 221 S-65) on the shelf and intend to replace when time and interest come together. They look like a treat to do. Didn't think I would need to purchase another wrench in my lifetime but I don't have the one for that front accumulator that looks to be about 27 or 28mm.

 

The low pressure accumulator is in the rear of the car, on the driver's side, near the rear differential. It's mounted high above the axle and exhaust, so it will certainly be an adventure to replace (but I think it will come out without disassembling the whole car).

For the front accumulator, I just needed to remove the underbody panel and the lower horn. Then I used a big rubber strap wrench around the whole accumulator to unthread it from the valve block. I also don't have a 27 mm wrench, but there is basically no access to the hex unless you remove a bunch of hoses.

For the rear accumulator, it's a real treat. First, remove all the trunk paneling to gain access. Then from below, remove a diagonal cross brace, left side exhaust/muffler, and muffler heat shield. Then you'll have access to the 3 bolts and hydraulic connection for the rear accumulator from the underside of the car. I don't believe this really improves access to the low side accumulator, so I don't think there's a big advantage there. The return accumulator is also the most expensive ($366)

 

Thank you! I will put her on the hoist tomorrow and get real about finding that low pressure accumulator. That is the one I don't have. I suspect it may be why I'm able to hear certain noises that fit with oil being released cyclically from what sounds like under passenger side rear seat. When I do this it will be all of them and a rodeo. Should be a hoot.

 

My car was making a funny high pitch sound (like air in the lines) after startup and the first few MBC actuations (vehicle raise, bump, or turn). It hasn't returned since replacing the front and rear accumulators.

 

How many miles and what year/model is your car Turbo? I hope I’m not looking at accumulators for a long while.

 

My current W222 is a 2015 S600. Just rolled over 100K this week. The ABC system started making the air in the lines sound a couple weeks ago.

On my old 2003 W220, both the front and rear accumulators had failed between 95K and 120K miles, and the return side regulator failed by 150K miles. After those replacements, the ride height sensors, 2 lines up front, 2 struts (failed travel sensor and external fluid leak), and a vertical accelerometer, the system was still working at 197k when I sold it. Be proactive, look at the struts for leaks when you change tires, and have Xentry or a similar diag unit to troubleshoot sensor issues. It's really not too bad if you are prepared. I survived the first gen system, so I figure the newer systems should also go the distance.

For reference, I had used Corteco accumulators front and rear, Amazon generic ride height sensors, ebay used OEM accelerometer and struts. The total cost of all of the ABC parts was under $1,000 in 100K miles of ownership.

 

That’s what I’m gonna do when I need struts is get the ones on eBay. 400 each. They are like 4000 each at the dealer for the OEM ones. If the small seepage I have on the right front strut gets worse ill Just do that one for now. The stealership wanted to replace all 4 of them now. Lol. Not gonna happen. Hopefully the fresh fluid and filter I put in will help out.

 

Is the rear accumulator the one you can see in the trunk near the battery? I'd love to see a technical document explaining all the functions and operations of the system if anyone knows of one. The discussion here is very helpful but it would be great to get the complete overview.