Two days ago I was on my way home after dinner, and when I pulled onto the highway, I got the white 'abc - visit worksop' message. I got off at the next exit and opened the hood. I saw a very little bit of oil around the ABC reservoir. I checked the ABC oil level and it was half-way between min and max marks. I figured I probably had a small leak but was going to try to make it home as I was still an hour away.

As soon as I started the car, the white changed to red 'abc - drive carefully'. I shut it off immediately and called the tow truck so as to not cause any further (and much more expensive) damage.

Now, rewind about 3 months ago when I started reading about accumulator failures and now that I had about 80k on the odo, I figured it might be a good idea to replace the accumulators. I attempted to do the 'bounce test' and the front end was fairly stiff, but the back did have a little more give to it. From what I have read, front and rear should be very stiff, but there was no video to show what exactly that meant, and I didn't find anything that stated if the engine should be running or not at the time of the test.

I figured all is probably okay since the car didn't bounce like a caddy over bumps. Well, fast forward to yesterday when I took it to my indy (because I didn't know just how big the job would be and didn't want to mess around and cost myself even more). He took one look at it and said one or more accumulators had failed, causing excessive pressure buildup in the system and shooting the oil out of the reservoir. Obviously if one accumulator is bad at 80k, the others could all be close by and I don't want to repeat this experience, so I am having him replace all of them while in there.

The lesson: I should have just replaced them 3 months ago as inexpensive preventative maintenance given the mileage of the vehicle. Then I could have just done it myself and avoided an expensive tow.

So, if anyone can provide me the proper instructions for the 'bounce test' (with a video to demonstrate how hard to push, and exactly what reaction we should expect, and if the car should be on or off) that would be great. When I get the car back, I will make one myself so others can see how it should react with good accumulators.

and while he is in there I am having him replace the front valve block with the updated version because after 3 days of sitting, the front passenger side drops. I figured if he's in there anyway and already replacing filter, oil, and doing the rodeo, I may as well just do it now so I don't have to spend more in the future.

 

Yeah the ABC's on the SL are no joke, I try to the the problem resolved asap when something seems ready to fail, I think once I extend my warranty one more time, and I'm off it, I'm gonna look into coil overs, If a SL65 Black Series runs on coil overs instead of an ABC system, I'm sure there has to be a way to convert for regular r230 models

 

According to Brian @ Strutmasters the SL500 strut coilover conversion will work on the SL55s BUT ... he says the car would ride a little higher. That should be solvable by lopping off one coil on the spring or using a softer spring rate.
Anyone willing/able to check this out? Could be a huge savings.

 

Got my baby back. Luckily, the bad accumulators did not (at least immediately) destroy anything else and I shut the car off before the pump ran dry. And HOLY C*** this thing rides sooooo much nicer now. I thought it was smooth before. OH MY G*D. HUUUUUGE difference with new accumulators!!!

So, if your car has around 80k on the speedo, I highly recommend replacing your accumulators. They are most-likely shot, causing pressure spikes within the system probably causing damage to hoses and components, not to mention how much nicer the ride is with fresh 'nitrogen *****' as the dealer calls them. Preventative maintenance and a better ride? yes, please.

While they were in there, I had my front valve block replaced with the newer version to fix the drooping when parked for several days, and my rear accumulator cleaned to correct the vehicle very slowly raising the right passenger corner while running and stopped.

 

what was the cost? dealer or "your guy"?
thanks.

 

$1200 for accumulators, $1900 for front valve block, $350 for filter/fluid/rodeo.

Prices included labor. I know there was good markup on all the parts as well, but more than a job I felt comfortable tackling myself, and with the ABC system I wanted the peace of mind having them do the whole job.

I look at it this way...the car has 80k on it, and the parts I replaced should go another 80k. Worst case, I replace struts/pumps/hydraulic lines as needed if they should need 'refreshing'. I love the car, and respect the technology behind it. I just wish the engineers designed the stuff to last 200k instead of 80k

 

The engineers did, but MB mgmt opted for the lowest bidder when it came to parts. If you look at the new parts they are an update over the old.

 

It's also true that parts designed for 180k miles don't all uniformly fail at exactly 180k miles. There is a bell curve to the failure rates, and your experience is but one data point in the statistical soup that makes up MTBF.

I would expect (based solely on wishful thinking and semi informed opinion) that most of the hard to replace stuff is designed (and manufactured) to go 250k + miles at the 1st std deviation point.

For example IF (hypothetically) the MTBF is 320k miles, and the st dev is 75k. THEN the design MTBF would be 325k miles, and 250k miles would be exceeded in 67% in of the instances. IF the above were true, then your 80k mile failure would represent 3 std deviations, which would not happen 99.7% of the time, ie is a 3 in 1000 occurance.

Of course, this all has to be tempered against OTHER considerations... namely weight, performance, cost and fuel economy. And suspension parts, even complicated expensive ones, COULD be deemed consummable and designed for a 100k mile major service.

I would LOVE to be able too the actual design criteria set by the various mfrs... but you can bet that will forever be closely guarded trade secrets.

 

grane, that's one of the reasons I opted to replace the front valve block instead of clean it, for the new design so I hopefully won't ever have to deal with it again. time will tell, I'm sure.