We have a 2004 MB CLK 320 (W209). Several months ago, roof function failed. We discovered no fluid in hydraulic pump reservoir and replaced fluid. This was successful but after a couple of days roof failed again, and pump reservoir was almost dry. My son observed fluid leakage on ground; his best recollection was that it was behind left rear tire. Earlier today, I began a dialogue with Klaus Witte, who gave me some suggestions and suggested I join forum and post my problem for benefit of all.

Klaus's response was, "if it was dripping behind the rear tire, then the leak could be directly from the pump, a hydraulic line going to the pump, or the left case cover lift cylinder which is right next to the pump. You would not need any shop instructions to examine that area closely. In particular, check out the area around and under the pump, and the bottom of the left case cover cylinder. If you don't find anything there, then we can move on to the main lift cylinder in front of the rear tire, which is a lot of work to get to".

I haven't had a chance yet to follow up.

I'm really impressed by Klaus's professionalism, and knowledge. He's a real asset. I actually look forward to doing business with him.

MH Black

 

It can be a pain to get to some of the lifts, but not all that hard to see them from above. If you have a leak big enough to empty the reservoir in a couple days it should not take too long to find it.

 

Today I got an opportunity to look at area around hydraulic pump. I couldn't see any collections of hydraulic fluid around pump, hydraulic lines, or the adjacent cylinder. We lowered top manually, and didn't find any leaks in the top well or around cylinders that you can see. Should we try refilling reservoir and see if leak recurs after opening and closing a few times?

 

Any leak that big will not be hard to find, but the oil is so thin and clear that it does not surprise me that you cannot see it after several days. If it were me I'd refill it, but I'd also go buy some dark colored paper towels like the blue ones from home depot or even the brown kind from public bathrooms and stuff them under everywhere the leak can be coming from - not to catch the oil, but to see the leak. Then run the top a little at a time with someone watching back there. If you run it a bunch you may just have a wad of soaked towels and learn nothing.

 

I filled reservoir to max line, and was able to operate top. I found fluid running down black metal bracket adjacent to both right and left main lift cylinders. Still nothing around pump so maybe fluid seen on ground behind left rear wheel was a red herring.

 

Sounds like you have two bad cylinders. But I'd still try to isolate further - make sure you don't replace cylinders to find that the lines are bad. Has to be coming from someplace to run down the bracket.

 

I appreciate your advice. This may be beyond my DIY capabilities.

 

The main lift cylinders 2098000772 and 2098000872 are the ones that take the most labor to get to, and those are obviously the ones you see leaking now. The leaks tend to start at the bottom of the cylinders.

If you had a leak from a hydraulic line, then you would see it spraying near a hinge of the convertible top frame.

It sounds like you have a significant leak. Your profile does not show where you are located (yet). I would guess that you are in a fairly warm climate, and I am certain that you will soon have more cylinders failing. The next ones to fail would be either the top lock cylinder 2098001172, or the two tonneau cover cylinders 2098001272. It is not much more work to remove the remaining cylinders, and you get a great package deal from Top Hydraulics if you send in all seven cylinders at the same time. We charge a little more than what one single tonneau cover cylinder would cost you new, and you get back seven cylinders that will last much longer than brand new ones.

Don't feel bad - this would have happened sooner or later. It is part of the cost of ownership for a convertible. The need to upgrade the cabriolet hydraulic cylinders will arise for any modern convertible, unless it gets wrecked prematurely. The next step is removing the cylinders or getting quotes for cylinder removal and replacement labor, and sending your cylinders to Top Hydraulics.

If you are not much of a DIYer, then the important part is finding a shop that can remove and replace the cylinders for you without charging you an arm and a leg. That can be tricky, because many shops haven't done this job yet and will be padding their numbers. Retired MB mechanics would be good for this, as well as some body shops. The majority of the labor is in removing the rear seat and the inside quarter panels (panels next to the side) to gain access to the cylinders.

Klaus

www.tophydraulicsinc.com

 

Klaus has talked me through establishing whether the disappearing fluid is a hydraulic line or a cylinder problem. His guess is that since it happened without warning and I lose the entire pump's storage before I get through the cycle once, it sounds like a line failure.
However, in manually opening and closing the top, I now have an issue with a 'top in operation' warning light in the dash. Of course, when that happens, the trunk latch won't work remotely and the windows don't seal.
Before I dig any deeper into the hydraulic fluid problem, what can I do to get the system back to square one? It's still top-down season here in the South and my wife is getting cranky.

 

gitfidler, welcome to the forum!

The signal from some micro switch must be indicating that not everything is latched and in place on the soft top, if you are getting the "top in operation" message, which will prevent you from rolling up the windows or opening the trunk.

Just to give a little background, there can be problems with the hydraulic lines going from the pump to the cylinders in W209s when they have not been installed perfectly. Sadly, the lines used in the W209 CLKs cannot take much strain in the axial direction, which means they can develop heavy leaks if they get pulled on too hard. This strain usually occurs near the hinges of the soft top, when the hinges are collapsed. Most commonly, we see failures on the lines for the two bow tension cylinders 2098000972 and on the lines for the top lock cylinder 2098001172. Adding insult to injury, Mercedes has been out of stock for replacement lines lately (guess why?). Top Hydraulics manufactures much tougher lines as direct replacements. http://www.tophydraulicsinc.com/en/24-w209-clk

For clarification: hydraulic cylinder failures are much more common than hydraulic line failures. Every hydraulic cylinder will eventually fail, but only poorly installed lines will crack during the expected life span of a CLK. Let's cover more details on the lines once you have ascertained whether it is indeed a line failure or a leaking hydraulic cylinder.

gitfidler, I believe you were moving the top manually to see if you can find the source of your hydraulic leak. Again, the signal from some micro switch must be indicating that not everything is latched and in place on the soft top, if you are getting the "top in operation" message, which will prevent you from rolling up the windows or opening the trunk. If you feel that you have fully closed or opened the top and latched the tonneau cover (also known as case cover or storage compartment cover), then some micro switch must have been dislodged. The prime candidates for that are the ones inside the storage compartment, indicating when the rear window is in position and the tonneau cover is closed. They are located inside the brackets that the tonneau cover lands on when it closes.

Please let us know what you find.

Klaus

www.tophydraulicsinc.com

 

So, here's where we are. After removing everything from the rear inside of the car (that's a lot of stuff!) we got the leaky cylinder out; Klaus check your mail, it will be on it's way. We noticed that there was a piece broken on the switch you described, that's inside the brackets - that's an easy fix. We tried jumping the switch wire but that did not solve the 'top in operation' problem, so we'll see if the new switch fixes it. We're getting pretty good at reupholstering the back of the car., probably do it in my sleep!

 

I am in the tail end of a clk500 top issue. I think that Klaus is the best. I also believe it would be best to send all the cylinders and pump to be refurbished. if one cylinder ahs failed the rest and the pump aren't fay behind and the cost of tearing the car apart for every failure can exceed the cost of a blanket treatment of the problem.

 

Correct, jd, but we'll try one and go with the whole package if we need another. After a couple of times the whole process is getting easier. I still hate mechanic-work.

 

To bring the problem up to date, we just finished installing all 7 cylinders. This is the result of lots of help from Klaus of Tophydraulics. The top will open without problems. On trying to close, the closing of the tonneau cover stalls in the upright position. By intermittently pressing the down button, the cover eventually comes down and locks in place. It seems that it descends on releasing the button The dash continues to show "top in operation". Does anyone have more suggestions?

Mickey and Scott

 

Air in the lines?

 

Congrats on getting the DIY replacement of all seven cylinders done! I checked with the technician who worked on your cylinders, and he confirmed that most cylinders had seals that were close to failing. Thus, you clearly did the right thing by having us upgrade the full set.

If the tonneau cover doesn't even start to move after the top has latched above the windshield during the closing cycle, then I would first check the micro switch near the top lock cylinder A 209 800 11 72, which indicates when the top has latched above the windshield. It may have been bumped while you were working on the top lock cylinder, or been disconnected. If the top controller does not get the signal that the top is latched above the windshield, then it will not move on to the next step, which is lowering the tonneau cover. That would also be consistent with you getting the "top in operation" signal in the instrument cluster even after the tonneau cover is down.

(I don't know how repeated pushing of the button tricked the controller into moving the tonneau cover, unless there is an intermittent problem with the top lock micro switch or its wiring, or unless the tonneau cover manually moved down part way, and then the controller didn't check for the top lock micro switch signal to continue operation.)

FYI, air in the lines is not a problem, as long as there is enough fluid in the pump. The system is self venting.

Klaus
Top Hydraulics, Inc

www.tophydraulicsinc.com

 

Thanks to Yidney and Klaus for your timely responses. We'll check out the microswitch. Also we're getting error message that SRS not functioning. We've checked the electrical connections to rear airbags and they're ok.. Is this possibly just an error in memory that will eventually clear or does it have to be cleared and further investigated. Almost never have passengers in back seat.

 

I am unable to see any electrical connections in the vicinity of lock cylinder or wiring anywhere in the front header. Is there anywhere else to look? Thanks.

 

I must apologize. Most convertibles have their "soft top locked" micro switch in the locking mechanism near the cylinder itself. Looking at WIS now, I see that the switch is in the windshield header. It is still worth checking out.

There is also a little known "soft top open" switch on the left side next to the rear seat, above the rear airbag. Make sure that it is in place and connected.

Klaus

www.tophydraulicsinc.com

 

The limit switch is in place. Connections seem intact. Does anyone out there know a good independent mechanic in Pittsburgh area?

 

There is only one SRS error that will self-clear, which is if the passenger seat weight sensor gets an erroneous reading while driving, as might happen of you tossed a heavy item into the seat while driving. That error goes away upon engine restart. Otherwise, SRS errors need to be properly diagnosed and cleared with a tool such as SDS (Star Diagnosis). Generic OBDII scanners won't rear/reset the SRS system.

If you are going to get a tech to check and reset the SRS codes, then their system should also be capable of reading the soft top control. Check it's errors. It may need to be cleared first (to get rid of the old errors from the bad cylinders) then re-read after operating the top.

Oh, and one final thing - a weak battery can prevent the soft top from opening and closing properly. Try it with the engine running.

 

Thanks Rudeney. I really appreciate your input. The car was driven for awhile without the rear airbags, while waiting for cylinders to be refurbished, which probably explains the SRS error.

 

Klaus,

Do you have a picture that shows the location of the switch in the windshield header. I couldn't locate it.

M

 

This is it:

http://benzbits.com/w209/soft_top/li...20position.pdf

 

Rodney,

Thanks so much. We'll check that out.

M