Kimberley

Just got hammered at the dealership on replacing rear hydraulic cylinders...then hammered again when they replaced the hydraulic fluid and the front cylinder began leaking. The front one leaked all over me and the interior of the driver's door AFTER I left the dealership! Needless to say, but it is back there again to now have the front cylinder replaced. Was supposed to take mountain drive tomorrow and now will have to cruise in a loaner C300 with a sunroof. Sucks. What else in this blasted hydraulic system will fail?

RussWhite

The passenger side hydraulic cylinder used to raise the top actually fractured near the bottom and ended up in two pieces. All the fluid pumped onto the floor and then to the ground. Estimates for repair from the dealer took my breath away. I spent a lot of time with the shop manual - especially figuring how to open and close the top manually. I then ordered the cylinder form a dealer and replaced it myself. Top works great now. On my CLK 350 there are a total of seven cylinders and numerous limit switches. I found a broken limit switch that may have contributed to keeping the hydraulic pressure being on longer than necessary, but I still don't think the pressure should ever reach a level sufficient to fracture a cylinder. Hope you get things resolved soon.
Russ

Top Hydraulics

Kimberley,

Unfortunately, leaking cylinders on W209 CLKs are becoming quite common now. We upgrade lots of these for shops and dealers, and there is a growing contingent of DIYers sending us their cylinders to be rebuilt.

This is good for our business, but it's really very disappointing how MB has used seals in the W209 cylinders that disintegrate even faster than those in older convertibles. The cylinders are crimped together, which makes it impossible for DIYers to replace the seals, even if the seals were available. I'm attaching below a photo of the seven cylinders in your car's top, and a schematic with the rough location. The same schematic is available on our website, as well: http://www.tophydraulicsinc.com/diag...209diagram.jpg

The decay of the seal material is a chemical reaction that gets accelerated by heat. Most people see the front locking cylinder fail first, because it can get exposed to more heat in the car's top. However, once you see any of the other cylinders failing, it is almost guaranteed that all cylinders are in bad shape. The reason is, the six cylinders in the rear are exposed to about the same temperature, so the decay rate of all cylinders in the rear is roughly the same. All cylinders use the same kind of flimsy seals, which will make them fail more or less at the same time.

Regard it as the cost of owning a fancy convertible - almost all modern convertibles will have cylinder seal failure at some point, unless they get wrecked prematurely. We are proud that we have a solution to fix the problem, and at a much lower cost than buying new, inferior replacements.

Attached below are a picture of all seven cylinders in your cabriolet top, and a schematic with their locations.

Hope this helps others in the future.

mnje350

This is why I bought an extended warranty.