TomZVB

Need some guidance if anyone has experience with the following…

While out Saturday, I was in stop and go traffic on a very bumpy city street and had a situation where there was a brief puff of smoke from under the car. It had a chemical smell and quickly dissipated. It was very hot and initially I thought it could have been trans fluid since it came from just behind the passenger seat, right side. The car was acting fine - no issues. I got to my destination and parked. Saw nothing. No leaks or anything. Four hours later, I came out and again nothing. I drove home and put the car away for the night. I thought that maybe I had run over a plastic bag?

Next day… no issues. I backed the car out of the garage. No oil on the ground. Nice and clean. We went out for a drive and had lunch for my bday. Then got caught in downpours. Came home, dried of the car and ourselves. All good.

This morning I came out to the garage and noticed the car was wet under the front left. My garage takes time to dry so at first I thought it was water. I backed and went back in to check the ground (always do). This time it was clear oil. Also, the car made a strange sound when I started it (like the ABC pump was low at first). I went back to the car and saw that it was dripping fluid off the frame right behind the left front tire.

What did I break?

I’ve heard a couple of times a slight chirping sound when the car falls off the step of the garage transition. I’m thinking maybe the accumulator went bad and that the reservoir overflowed at shutdown due to air displacement (read that this could happen on the R230).

I’ve already replaced the pulsation damper up top at the pump. She now has 96k miles on it so I’d expect these to start going.

Anyone experience similar?

TomZVB

Quick update….

Just got home and popped the hood and lo and behold we have ABC fluid all on top of the reservoir housing and pretty much all down the inside of the engine room. That’s going to be fun to clean up.

So not a hose but it sure pumped out a lot of fluid it seems.

Will need to investigate further but I’m thinking one of the accumulators gave up the ghost and now there’s a bunch of air in the system pushing out the fluid.

TomZVB

I looked through WIS and it looks like this isn't exactly an easy job to do considering the hoses and valve block have to come out. I guess there's a special wrench needed to to fit in the tight space as well. Unless any has any pointers that I'm unaware of I think I'm going to have my local shop take care of everything. Looks like the job only calls for 1.4 hours (though I might be reading that wrong).

Anyone messed with this job yet? Seems that there isn't much out there on the R231 and ABC.

crconsulting

What is the part that has failed? accumulator, hose or something else?

TomZVB

More than likely the forward pressure reservoir (accumulator). They’re a wear part so I was going to have both replaced.

The telltale sign is having fluid dump out of the reservoir.

I looked at last night for a brief moment… fluid all over the top of the reservoir and inside the filter cap. Looks like the air from whichever one gave up the ghost forced the fluid out. Haven’t tried refilling yet. The car is holding height and there were no warnings about a problem with the ABC.

crconsulting

Definitely a bit of work, and messy…
I remember you recently did the pulsation damper too. How many miles on the car?

No errors in XENTY?
This one here. https://mbworld.org/forums/sl-class-...c-dampers.html
Those are a pain to get to but doable. But better be sure that’s the faulty part. 👍


Good Luck!

TomZVB

I’ll fire up Xentry in the morning to see if there’s anything in there.

96k miles on the clock, and yes, I replaced the pulsation damper back in December.

Reading through posted literature for ABC diagnosis and repair, accumulators are pretty much the deal when this happens. No warnings. No issues. The car was raising and lowering as it should. Given the immediacy of the puking, I’m going to replace both.

I made a call today to the local independent to get on the schedule. I figure anything I can hand over from Xentry will help. And maybe get the parts in hand before dropping it off. I really don’t feel like messing with it.

crconsulting

I think around 96k is about right for this iteration of ABC. That’s a pretty good run compared to the typical R230. Accumulators are consumable items just as a strut would probably be replaced at that mileage and also a consumable. I would have them look at the hoses too…. That’s a nice car. Since you’re there, and if you plan on driving the car another 96k, consider future availability of parts too while you’re there. Seems like many R231 parts are already discontinued.


Good Luck!

TomZVB

I’ve noticed that parts are becoming NLA from MB. The aftermarket is picking up some but not a lot. I plan to keep the car for a long time - my favorite to date and I’ve had many.

Some updates…

I cleaned up everything. Lost about 8-12 ounces of fluid. I sprayed down what I could get to with a mild degreaser/detergent and hosed off after verifying that it would no longer puke.

I started the car and ran suspension up and down a few times before filling. There were no pump
noises but, but it did make noise lowering from the raised position - a squeaking/groaning sound. After three cycles it was quiet.

Then I hooked up Xentry. No errors and all tests/pressures were right in line with specifications. I performed a rodeo - no issues.

From there I drove the car a little after filling with fluid and no more puking. I know the problem isn’t solved but at least I can get it to the shop to have the accumulators replaced (the indy shop I’m using is about three miles from me). I need to get a B1 completed so I figured I’d have him do it all at once with my parts that I’ll get from FCP Euro. With my work schedule, I don’t think I’ll have the resources and time available to do myself.