Hey Guys

So the front hydraulic cylinder on my 2009 SL550's convertible top just blew out. I've been searching for videos showing the whole replacement process, from start to finish, but haven't had much luck finding anything comprehensive. If you have any links you can share, please post. Also, any idea how big of a pain this job actually is?Also, any thoughts on preference for Top Hydraulics or Cabriolet Hydraulics? Cabriolet's about a 3-hour drive and I'm trying to figure out if DYI is even worth it. Cheers!

 

I just Googled "mercedes r230 front cylinder replacement" and lots of stuff comes up. This one looks pretty thorough -

.........although he uses an O-ring style repair kit. The O-ring kits are easier to install but they don't last very long because it's just not the right type of seal for this application. The only reason an O-ring is used is because an O-ring can be stretched/rolled over the clevis for easy installation, where a proper U-seal requires the clevis to be removed from the shaft for installation; there is no way to stretch a U-seal over the clevis, the seal will tear. So the U-seal repair is more difficult but will last at least as long as the original seal (probably longer, since seal materials have improved over the last ~20 years).

Cabriolet Hydraulics offers a cylinder rebuild service that includes splice connectors for the hydraulic lines. This allows you to cut the hydraulic lines to remove the cylinder for rebuilding, making the job MUCH easier. Without those splice connectors you have to remove and reinstall the cylinder with the attached hydraulic lines which run all the way back to the pump in the trunk, which is a major pain in the a$$.

There are DIY rebuild kits available that have the U-seal with additional hardware and instructions that allow you to remove/reinstall the clevis from the shaft for seal installation. I chose to spend the extra $$ to have a pro do the rebuild, sent my cylinder to Cabriolet Hydraulics. I think it was about $150 total.

Note - be careful to protect your interior with some sort of drop cloth when removing your headliner - the headliner may be holding puddle of hydraulic fluid which will spill as you remove it. Also, there's about a 99% probability that you'll need to re-glue the clips along the rear edge of the headliner. It seems the original glue doesn't usually hold very well. No big deal, just clean off as much of the original glue as possible and re-glue with epoxy.

 

The front latch and 2 roll bar lock pawls don't have the clevis. You can install new u seals yourself on those.

If you use a rebuild service, Cabriolet is better using their couplings because you don't have to remove hydraulic lines all the way back to the pump.