sushistrip

Recently purchased a 2003 S55 with about 80k miles. I had a pre-purchase inspection done and thoroughly test drove the car and it was perfect. The previous owner also replaced all 4 accumulators/dampers and the ABC pump within the last thousand miles.

While driving the car home there was a point at which the steering went very stiff as well as the suspension. I was driving from Utah to Kansas, so had to go through the mountains, and it was about the point where I hit higher altitude and colder temps that I noticed these issues. The road conditions were quite bad and it was extremely difficult to keep the car pointed straight because it took quite a lot of steering input to get the wheels to turn. It was like the deadzone on the steering increased by about 20 degrees. During the remainder of the drive home I had no lights come on, except for a brief moment when the tires broke loose on the snow the ESP light flashed, however I understand this is normal when traction control catches a tire slip? On the trip home the car also picked up a vibration at basically any speed, in Park or Drive, and it also has this weird pulsing vibration on cold start that goes away after a minute or two.
Ever since I got it home the steering is quite a lot stiffer than it was initially, and the suspension has that "go kart" quality to it now. It's not unbearable, but not what I remember from the test drive. I had a shop do me a favor and scan it with an Autel, and it had two codes for ESP and ABC Control Module. I do not remember which codes they were but he cleared them and they have not come back, however it has not remedied the issue. When first starting the car and taking off, the steering is quite soft, but after about a minute it becomes stiff again, as well as the suspension. It is most noticeable on the highway, where the rebound of the suspension is harsh rather than floaty as I would expect.

There are currently no codes, no dash lights, no noises when turning the steering wheel or raising the suspension, no sagging, no leaks, no smells.

I recently bought an Autel MaxiPro MP808, which seems to be able to do everything that people claim Star to do (it's also returnable and usable on other cars). I've read all the suspension/steering related sensors available and they all seem normal; wheel rpm, accel, level, height, steering angle, etc. I see there are a few control adaption functions for the ESP and ABC modules, however it says you only run these after replacing components. I have not tried a rodeo yet, as nothing seems to point to a mechanical failure. Would unplugging the battery or disconnecting the ABC/ESP control modules be worth a try? I would think any kind of electrical problem would throw a code.

For the vibration, I think it is likely that the engine/trans mounts gave out on the trip home (it was a sudden 900 miles that was put on the car in the span of two days), and I will have a shop look at them next week.

I've done a few 30 minute drives to try and see if the control module codes would come back, but I'm thinking they were just related to when the wheels slipped on the snow.

It also has a valve cover gasket seep, which I plan to fix. Also, it would seem the intercooler pump went bad as after doing a pull I have no power, and there was a code for it. These items are pretty straight forward though.


I will update after I have a shop take a proper look at it but this steering/suspension issue really has me stumped.

maw1124

How is the ABC fluid level, and do your records show that was changed along with the accumulators? Also were ALL of the accumulators (including the return and the pulsation damper)?

maw

sushistrip

With the car cold/off the fluid level looks fine, I will check again while running. The guy only gave me receipts for the part numbers so I don't know what all procedures were done after they were changed. All four gas accumulators were changed, I can see the part numbers for each one. Now, I haven't been under the car yet to verify that...I would think it's pretty apparent visually if they are new or not, I will do this when I have a shop look at it for the vibration issue.

After doing the steering reset it is very light/normal for about the first 100 feet, then stiffens up again.

The system IS working, because there is no dive and no squat when braking and taking off from a stop, it's just stiff! =(

maw1124

Yeah...

It "acts" like there's not fluid in parts of the system (including the steering rack) at times, it seems to me. That leads me to think: (1) not enough fluid; (2) old, coagulated fluid moving around inefficiently so that the struts and dampers are full but the steering rack isn't, at any point in time; (3) a failing tandem (ABC & Power Steering) pump; or (4) a failing power steering rack (never seen one of those, actually).

You can see why I focus on (1) and (2) before (3) and (4).

If the receipts are from a dealership, I'd be willing to assume the proper procedures were followed (it's well documented and high stakes), including new fluid, filter, etc. at the time the dampers were changed.

Make sense?

maw

sushistrip

I'm gonna take a wild guess and say the fluid is pretty disgusting based on that pic...

I can find something to suck some out of the reservoir to get a better look but that's pretty telling. I would think relatively fresh fluid would be bright green.

Is it possible they topped it off so it was fine for a bit but once it mixed with the dirty fluid these symptoms started?

maw1124

Not only possible, but probable and suspected. The bright green fluid wouldn't stay that way for long. But you can tell that I give people zero credit for accurate maintenance of these cars unless the record keeping is flawless. Slap on some new accumulators and top off the fluid (leaving tons of old fluid and two sh*tty filters there) is something I would put past no one. Have your trusted service facility replace the fluid and both filters (most people only know of one -- apparently there's a second one down near the pump), run rodeo, the full procedure, and see where you get.

maw

PS... don't drive the car long like that, lest you get blown ABC lines, a failed pump, blown struts, etc.

sushistrip

Any reason I can't do that myself? The procedure looks easy enough. Tbh I don't trust any shop around here to do it correctly, they just don't see enough of these cars.

Are you speaking of the filter inside the power steering reservoir? Afaik that's a separate system that would need flushed separately?

maw1124

Well, you CAN do it, but the system is notoriously picky and contamination is a problem, so for those reasons I've mostly left it to dealerships (or people who are better than dealerships) and paid whatever that meant.

There's one filter in the reservoir, and I recently learned (on like my 3rd fluid and filter change) that there's a second filter down near the pump. And then I thought about it, of course it makes sense for there to be filters at BOTH the reservoir AND the pump. It's a Mercedes -- we should be happy there aren't filters at each corner going into and out of the struts. I'm only half joking.

No, these are not separate systems, hence the "tandem pump". The same system that's flowing Pentosin through the ABC system is also feeding the power steering system with the same fluid, which is why it makes sense that there's a second filter.

The rodeo requires a computer, not just "raising and lowering" the car with the button that people seem to have confused for that.

Since I'm no mechanic and have only observed others doing this work, my knowledge of it isn't exactly encyclopedic and should therefore not be regarded as such.

GL

maw

sushistrip

I should clarify when I say "separate" systems. They don't share fluid, and the pump may be one unit but there are different components pumping the suspension fluid than the steering fluid. The tandem pump is one unit that lets the power steering pump and suspension pump share a drive pulley/shaft, but that's it. The pump for the suspension is a piston pump on the front (closest to the pulley), while the pump for the steering on the back is a vane pump.

Source: https://www.abcspecialist.nl/uploads..._watermark.pdf

maw1124

I'll take your word for it. But it's also why I've always let mechanics do it. This car is not a DIY project for me, ESPECIALLY not the ABC or steering system.

GL

maw

GrepAwk

@maw: Where is the”second filter down near the pump?”

I usually change the 2-micron filter on the end of the return hose under the cap for the ABC Reservoir. Let’s call that filter number 1.

Where is filter number 2?

maw1124

@GrepAwk I'm going from memory here, as he said it was "down by the return."

I just looked at this invoice and it's shown as a "steering filter". Sorry, no P/N but it was around a $10 part whereas the "Suspension Filter" was a $45 part. Hopefully that helps.

I guess it sort of helps that this guy is very well known and respected in MB circles globally, and his dad had one of these cars years ago. So he knows the platform well.

maw

EDIT… I’m assuming it’s this one (pic attached).



Located here maybe… https://www.carid.com/mercedes-benz-...ml?view=599768

See post #2 here… https://mbworld.org/forums/s-class-w...ng-filter.html

wfooshee

Yucky O-rings in the valve bodies will contaminate even newly flushed fluid pretty quickly. Before my S55 was killed by the flooding from Hurricane Sally, my plan was to do a valve body rebuild, then have the fluid-flush / rodeo process done. I had already replaced the accumulators, and that fixed the car sagging after driving for 10 or 15 minutes, but ABC didn't actually work; it just took a level at startup and stayed there. That was better than the drooping tail end, but not much.

sushistrip

Unlikely that the valve blocks are bad, car has been sitting for a few days now in freezing weather and hasn't dropped a bit.
My shop found quite a few small issues, none related to the ABC system, and none really surprising for a car this old.

Engine mounts are leaking a bit, so those are likely the cause of the vibration. He said the front wheel bearings are slightly bad, there's just the slightest amount of play on the wheel, so that could be contributing to my steering issues, but it's so subtle. I had a thought to check the torque on the lug nuts, so I'll do that this weekend.

This weekend I'll be doing valve cover gaskets, sparkplugs, IC pump, and abc flush. I'll update after that.

maw1124

If you're that handy, tackle the PS filter above. All of these fluids have cleaning agents in them so changing them multiple times only costs you time and money.

Also, fuel filter "just because" -- I've been through a couple of those. Since you're doing plugs, you might as well get that old filter out of there and see what "twin spark" and good fuel do to this beast.

Finally, you're probably due for transmission fluid (on time not mileage). I treat this as a 5/50 item like spark plugs, which is what's reminding me to mention it. 20yrs is coming up on 4x5yrs. Keep in mind that was a "no service interval" fluid from the factory so it probably has never been touched. Touch it now before it gets out of hand, then 5/50 thereafter.

maw

sushistrip

Just did an ABC fluid flush. Sucked out what was in the reservoir first, which was disgusting, and refilled. Replaced filter and ran the rodeo on my Autel to warm up the fluid. Pressure would fluctuate between 180-190bar, which I believe is normal? Ran a line from the return line to a bucket and poured about 12L of fluid while the rodeo ran, happens very quick btw.

It's so hard to tell, but I think the suspension feel is better? Steering is still stupid stiff. Some turns I have to use two hands. Nothing like if the power steering wasn't working at all, but definitely not correct. What's weird is the steering effort is stiffer that faster I'm going when trying to turn. For instance, backing out of a parking space isn't that bad, but turning through a light at speed is very stiff.

All I've done on the power steering side is check the dipstick, which looked clean. However, I've a sneaking suspicion that the fluid in the power steering side is maybe just not the right fluid. So I might suck out what's in there and put pentosin in, start the car, lock to lock a few times, suck out fluid, refill, repeat.

The shop also said there's some play in the front wheel bearings, as well as control arms, which could be contributing to my steering problems.

57staff

This looks suspiciously like a problem I have occasionally on my W221 S65. My power steering would become very stiff and I would get an ABC and ESP warning light. It would go away after a couple of days and return to normal. For my car it appears to be an issue with the speed sensors at the wheels. Probably tied to some SAM going bad.

maw1124

Good stuff. The hardware has nothing to do with it. Please continue with fluid and filter on the PS side and report back. If that doesn't work, then I would suspect some steering assist functionality awry, but obviously since that's more complicated let's leave that for last. This other stuff needs to be done anyway on a new to you car. If it's full of the wrong fluid, let's hope you can get it out. With any luck, it all comes out fine and just jammed up the filter.

Cheers,

maw

s55nyberg

Did u ever figure the stiff steering issue? I have same issue on my 04 s55. My abc pump is new with new fluid and filter

S_Holford

I hate to say it but I've lost confidence in just about everyone claiming they're mechanics because it seems like I've had one bad experience after the next when I've let people work on my cars. Is it just me or is it a rare to find someone that takes pride in doing a good job anymore? My background is prior aviation maintenance, now instrumentation and controls. I've also got about 30 years of mechanical experience under my belt. Also on that note, sometimes I just don't enjoy turning wrenches anymore.

I was tempted to let an indie perform my ABC flush, but (1.) they were asking $599, and (2.) I feel like attention to detail is lacking when it comes to my expectations (that's the jarhead in me talking).

Sorry for the rant...maybe I'm just getting old and tired of paying for mediocre service. The last time I let a shop "look at my car" it was there for 2 weeks, they left it unlocked in an unsecured lot, didn't fix a damn thing and gladly took my money to leave me right where I started.

maw1124

I think it's just you. Or maybe it's just me. Admittedly I've been blessed with pros who aren't guessing working on my cars. I'm back there with them, under the car, talking to them about what they're doing and why, sourcing my own parts half the time, and I've known them for decades. So there's that.

But yes, I'm close enough to the business to know that's not normal. There are tons of shoemakers out there. Hell it's tough to find a MB dealership who knows these cars anymore, let alone the 30year old 500E. So I understand where you're coming from. And if that wasn't enough, two of my guys have retired, but I have others and the folks they sold their businesses to know me and how I roll, so far it's been seamless. My family are all jarheads and I'm as picky as they come, having grown up wrenching on cars. But so are my guys.

Depending upon where you are located, people here can probably recommend pros. That's a real benefit to these kinds of boards.

$599 is about right for an ABC flush. The fluid is expensive and there's a lot of it. Plus it takes time and the computer to do the rodeo. As long as they use the right amount of fluid (I'd be worried about them removing half or some silly sh*t like that) I wouldn't flinch at that. Hope that helps.

maw

S_Holford

To touch on what you said without jacking the OP's thread too much....I've dealt with a lot of business that aren't fond of you sourcing your own parts, nor letting people into areas with work being performed. To be fair that's not even a huge concern for me, I'm more concerned with a certain level of competence.

In regards to the ABC flush price I suppose it's fair if you don't have the resources available. I do have a C4 multiplexer and dedicated laptop with Xentry installed. It just boils down to whether I want to do it or not to just save a couple hundred dollars. 12 liters of fluid is roughly $250-ish and then of course you have to deal with disposal afterwards.

sushistrip

Update:

Replaced engine mounts and trans mount myself, they were all basically shot. On first startup after replacing them I could immediately tell it was much smoother. I still have a pulsing/throbbing vibration around the 1200-1400 rpm range, and again up around 3000 rpm, however it has become less noticeable after replacing the mounts so it's definitely coming from the engine. This is in park, neutral, or in gear. I think the idle is a bit high, around 800rpm, but I need to drive it let it warm up and I'll report back.

maw1124

The low rpm vibrations are likely pulsation dampers (a particular type of accumulator). At this age they likely all need replacing if they haven't been already. Glad you got some of the vibrations out with mounts.

maw

sushistrip

According to previous owner almost all ABC components were replaced, save for valve blocks which were most likely rebuilt. Could be horse **** though. Since the pulsation dampener is cheap and easy to replace I will probably just do it to rule it out.