1996 SL500 Convertible.

As mentioned in my intro thread, this is a nice car given to me by my in-laws. The only significant problem was the hydraulic system for the retractable roof. There is a serious leak in or near one of the cylinders.

Nevertheless, I enjoy using the car with the top down, and I live in an area (Atlanta) that is prone to rain whenever the region is in the mood to rain. It's never wise to leave the top down outside for long periods of time here unless you are very confident in the forecaster's prediction. Therefore, the retractable system needs to work. I use it two or three times a day.

I took apart some of the interior trunk paneling and removed the spare tire in order to examine the source of the leak, and I was able to isolate the source to one specific cylinder. I still don't know if it's the cylinder itself or a line leading in. I was working into the darkness yesterday and didn't have a lot of time.

Coincidentally, I went to the MB dealership a couple towns away and bought a liter of hydraulic fluid for the roof system. As soon as I got home the roof failed to lift and close. I took out the spare tire and the resevoir was nearly empty. I poured in most of the liter. The roof then began to work again (and of course, the cylinder leaked again).

I used the roof two more times and it continued to leak, of course.


Anyway, back to the solution: I found the cylinder where the leak was located, cleaned up everything (including the wiring and other parts saturated in oil, and then had to figure out a temporary solution that would still let me use the retractable roof.

I found, of all things, a device used to hold a small Coleman propane heater that fit perfectly into a thick, screw-top container that holds (wouldn't you know it) about a liter.

I tested the roof out today, and sure enough the leak is significant. I lost about two ounces of fluid by lowering the roof once (as I left home) and raising it once (when I got to work). In general, it's losing about one ounce per activation.

The good news is that I finally have the leak contained, which will make it easier to continue cleaning the trunk area and protect the cables and wiring that were saturated.

I have photos that show my contraption. The layer of black duct tape isn't really needed where the funnel and the container join (it's a pretty tight fit), but it's there for safe measure. The funnel tapers and is fitted inside the screw-on lid of the clear container.

Now, all I have to do is unscrew the bottom container every couple days and put the fluid back into the resevoir. Yes, it's a hokey setup, but I prefer it to the dark spots on my driveway, and I'm not ready to put on the hard top yet (hey, it's only the second day of fall and I just got the car two weeks ago).

Within a few weeks I'm sure I'll be quite tired of checking the resevoir every week (or every two days), and will want to get this taken care of properly.

My question is: Is this temporary solution a bad idea? Is there something I should know that I currently don't know? Will the cylinder eventually blow completely and make things worse? Or could this potentially work and go on forever?

Oh, and sorry about the mess in the photos. I have some rags, cleaning solution, and a few other things wrapped up in that grocery bag, and I haven't put the interior panels back into place yet.

I appreciate any advice on this matter. I'm mechanically inclined (I love to fix things and have worked on cars my whole life, but never rebuilt an engine or tranny. I have, however, replaced exhaust sytems, drive shafts, brakes, alternators, compressors, and other minor things like that).

Thank you.

Mike (Atlanta)








Leaky cylinder





Funnel contraption surrounding the leaky cylinder

 

Mike,
These cylinders are not hard to repair, and there are several threads here on how to do it. If you repair just the one, you will soon have another start leaking. (been there and done that) It is best to go ahead and take all 12 out and get them rebuilt.

 

You will also want to replace the seals in the distributor on the windshield as it will leak as well. I spent over 20 hour removing & reinstalling all 12 cylinders only to have the distributor leak as soon as I cycled the top!

 

Klaus from TopHydraulics has rebuilt many units. Replace or rebuild all of them. The seals from Benz last about 10-15 years in my part of the world.
It has been a positive experience to see how you got around the MB auto "oiler" system! My leather interior was never softer after the front cylinders applied the fluid to my seats and linen pants! what a pleasure

 

I have a much better containment system in place now. I'll rebuild the cylinders in the spring.