Mercedes R230 front roof-lock cylinder seal repair
White Spyder traced a roof hydraulic leak to the front locking cylinder, replaced its sealing ring and reported three leak-free roof cycles. Later owners describe seal durability, rebuilt cylinders and a reassembly alignment problem.
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Preparing the roof and removing the headliner
White Spyder documented replacing the front roof-lock cylinder’s sealing ring. The account begins with padded wooden supports, partial roof opening and headliner removal. Several headliner mounts had detached, and the author reattached them while the liner was out.
Accessing the cylinder and its lines
With the headliner removed, White Spyder documented the cylinder bracket, hydraulic-line routing and retaining clips. One released clip flew far enough to be difficult to find. The author also highlighted a small green disc at a pin, then freed the lines as far as the B-pillar to bring the cylinder to a work surface beside the driver’s door.
The author’s cylinder opening and seal replacement
The kit’s instructions called for an access hole to reach the cylinder’s retaining ring. White Spyder photographed drilling the hole, removing the ring and withdrawing the piston, taking care around the nylon cup. The final close-up identifies a crack in the ring the author replaced. After reassembly, the author reported three roof cycles without a cylinder leak. That short check is not a service-life measurement; later replies disagree about O-rings versus purpose-designed seals.
A different owner’s rebuild experience
Leej, who identified a 2008 SL550, chose an outside cylinder rebuild with line couplers. The follow-up reports successful roof cycling but also says the added coupling length made the lines feel cramped. slkfla separately reported completing a similar rebuild on an SL550.
Reassembly: a later report of lock misalignment
Tomcat SL reported that one roof lock released while the other did not, with unequal gaps and inconsistent microswitch operation after reassembly. He said a small adjustment of the centre bracket brought the gaps and switch operation back into agreement. elMacko reported encountering the same centring issue.
Replies disagree about the seal choice
bobterry99 questioned the O-ring approach and its fit; elMacko argued for a purpose-designed cup seal. FxFormat nevertheless reported no leak after about 18 months, and cjhazard described three to four years of use after an O-ring repair. These are different contributors’ claims and follow-ups. They do not establish that the seal options are equivalent or predict a service life.
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