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Finally got around to replacing the "o" ring in the front lock cylinder on the roof thought I would document to process. I bought the repair kit on eBay for $15. It came with instructions for the R129. They were OK and the few photos were in black and white.
Started out by cutting two 16" long 2X2's and notched each end.
Covered each end with some micro fiber cloth for protection.
Raised the roof just enough for the two to prop it open when the system depressurizes. There are 5 torx bolts along the front end of the headliner that need to be removed.
Discovered that the rear tabs of my headliner had come unglued. This made removal of the headliner easy.
You can see where the oil had been pooling.
With the headliner out I re-glued the tabs in place.
There are also 2 more clips on each side of the headliner that were unglued that were repaired.
With the headliner removed you can see the front lock cylinder. There are three torx bolts holding the bracket to the roof that need to be removed.
Take plenty of photos of how the lines are routed as you will be removing them from the roof.
Cearfullyremove the "c" clip from this pin. They will shoot off with surprising speed. this one went about 6 feet and I was lucky to find it!
Be mindful when you remove the pin of this green disk.
Remove this "c" clip and pin and you should be able to wiggle out the cylinder. There are some dimples in the bracket that holds it in place just push firmly. Be mindful of the lines.
Clip the zip ties all the way back to the B pillar to give you enough slack in the lines to put the cylinder on a work table next to the driver's door.
There are several of these clips along the driver side that you need to free the lines from.
Cylinder out and on the table.
The instructions with the kit say to compress the cylinder all the way and drill a 1/8 inch hole 0.1 inch from the top on the opposite side from the hoses to access the retaining ring in the cylinder.
Through this hole, you can push the retaining ring in enough to use a pick to remove it. Took me a while to get it but I was being very careful not to damage the nylon cup on the cylinder shaft.
With the ring out you can remove the piston. The tool is pointing to the culprit. The white piece is the nylon cup.
you can see in this photo the crack in the offending "o" ring. Remove it and slide the new one over the end and reverse the process to re-assemble everything.
I cycled the roof three times with no leaks from the cylinder. When I check the pump in the trunk ( I had filled it with the correct oil earlier) the level of the oil had only moved the with of the indicator arrow. I attributed this to the loss of oil from the cylinder when I removed the piston.
I hope this helps others in tackling this project!
Good job mate, thanks for the well document procedure, we need more threads like this on common problems on R230. The other threads all have broken links, or it's been over a decade old.
Based upon the information in this post and my own experience with o-rings and R129 hydraulics I surmise your repair may leak within a year or so. The problem is a combination of using an o-ring instead of a seal and what I presume is an imprecise fit.
Last edited by bobterry99; 05-14-2018 at 09:58 AM.
The post I linked to earlier gives the seal size as "16mm O.D. x 9mm I.D. x 4.5mm tall". The author (a machinist by trade) could not source a replacement locally but eventually found one by Internet after an exhaustive search. Someone on the thread asked where he made the find but he did not reply...
If this seal on my '03 car were to start leaking, I would try to locate the proper-sized seal, of course, and do the repair myself. If I failed, I might choose to risk the eBay o-ring but would probably use TopHydraulics or Cabriolet Hydraulics.
In the event of a leaking cylinder Mercedes intends that the unit be replaced and not repaired, so there are no spare seals or other parts available.
Originally Posted by FxFormat
What did they use on the original lock cylinder? looks like a regular O-ring to me.
There are seals specifically designed for this application ("rod seal"), and they typically look like the attached photo. The profile is decidedly more complex than a simple o-ring.
Even if this o-ring lasts me a year i'll be happy, basically once a year i spend an hour of my life to repair this and spend $12. Seller actually gave me 2 o rings, so i can use one next year if need be.
Even if this o-ring lasts me a year i'll be happy, basically once a year i spend an hour of my life to repair this and spend $12.
But there is also the added hassle and expense of dealing with broken clips/hardware practically anytime you remove a trim panel on an R230 (the liner for the top, in this case).
Originally Posted by White Spyder
Where is top hydroelectric sourcing the seals they are using when rebuilding?
I doubt any of the rebuilders are willing to guide anyone to the source of their seals.
The seal is available from this U.S. source. Another source appears to be this one in Europe.
Last edited by bobterry99; 05-16-2018 at 01:16 PM.
But there is also the added hassle and expense of dealing with broken clips/hardware practically anytime you remove a trim panel on an R230 (the liner for the top, in this case).
I doubt any of the rebuilders are willing to guide anyone to the source of their seals.
The seal may be available from this U.S. source. The website is a little old, and that suggests to me the seller is no longer doing business. A viable source appears to be this one in Europe.
Too late for that lol, the clips detached from the liner long ago. The glue falling off is pretty common on these vehicles. I can try to reglue.
I've used hot glue to re-attach the clip hardware to various panels, and it seems to work very well.
Someone re-attached plastic parts to my driver door panel with hot glue at some point in the past. They all broke free by the time I had to remove that panel. I used epoxy.
Just did mine today, very helpful instructions by Spyder, cycled the roof a few times and checked the seal, no leaks. I'm going to leave the headliner off for a week and check for leaks before i put it back. In the meantime, gotta find out where the creaks and rattles are coming from. I feel like it's from the plastic tubing hitting the metal roof.
Little tip, i soaked the new o-ring in hydraulic fluid and let it sit in the sun while i remove the unit. It gets nice and soft and rolls over the piston easily, note that it'll feel loose once you stretch it over the piston, but it'll start to shrink and when you shove it back into the cylinder, it'll compress onto the rod and seal it. If this lasts me a year i'll be happy.
Just wanted to followup on a suggested source for seals posted by BobTerry previously. MBSeals does indeed provide an actual seal as opposed to just an O-ring. Konstatin at MBSeals is very responsive to any concerns and ships out your seals within a couple of days. The quality of the seals seem better than the stock MB seals they replaced, and the instruction on his website, along with pictorial step by step directions, makes replacing the front lock seals a breeze.
Thank you so much for the detailed pix & info - now I think I can tackle this. I'm glad to see you didn't have to cut any lines...
I did this on my ’97 SL 230, & this looks a little more difficult, but not as bad as the dealer price (I haven’t even asked) !!!
Especially since the dealer will probably replace the whole cylinder with the same bad O-Ring…
I thought they would have fixed that by now, so I only cycled the top once at the dealer…
Luckily also, the oil is not red anymore, cause it leaked into the car.
Last edited by JupiterJim; 11-30-2019 at 02:21 PM.
Reason: Added text
It's been 1.5 years now since i did my o-ring seal, it hasn't leak yet, and i use my top pretty often too when i drive. If it lasts me 2 years i'll gladly swap it out every 2 years for pennies and an hour of labor.
I assume I have to release the hydraulic pressure - in my car, it's on the left of the "tire", aluminum in black plastic 6mm - turn CCW 2X ??? How much fluid will leak out when I remove the cylinder ???
Last edited by JupiterJim; 12-06-2019 at 12:45 PM.
SO..! i have finished it all, replacing the top lock cylinder with one from cabriolet hydraulics..
went well, the couplings look to be pretty secure in how they close around the tubing..
i padded them so as to avoid and rattling against the metal of the top..
i am now at the point of dealing with the headliner part..
when i removed it it came away too easily..
it looks like this had been off before.. (i'll need to check the mercedes records to see if this job had been done before)
i reglued all the clip things, both the back and side clips.. used JB weld and it seems to have done a very good job..
NOW i can not get the damn thing back.. Headliner with al;l the clips re-glued and in the proper places.. you can see the rear clips are in two parts, one slotted glued to the headliner and the push in part slid into that slot.. finished job with padding which i later replaced with double sided tape (very hardy stuff) and thinner foam padding.. anyone want better pix just ask..
the rear clips refuse to cooperate so i pulled them apart and pushed the clip part into the holes at the back of the top..
BUT i now can NOT position the headliner so as to slide the glued on part of the clip assembly onto the pushed in part of the cilp..
so, please, any tricks on how to get it back in place correctly.. ?
I assume I have to release the hydraulic pressure - in my car, it's on the left of the "tire", aluminum in black plastic 6mm - turn CCW 2X ??? How much fluid will leak out when I remove the cylinder ???
i replied to your PM..
if it is leaking there should not have been much pressure or none at all..
when i did my top lock cylinder i loosened the plug on the top of the aluminum pump housing and a tine bit of oil escaped which i picked up with paper towels..
05-11-2018, 08:43 PM
