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MB World
My wife was moving while she tried to open the convertible hard top on her, new to her, 2005 SL 500. The top stopped almost completely open but wouldn't go the last little bit and the warning showed that it wasn't locked. After a lot of head scratching I figured out the the driver side was locked but the passenger side wasn't. I inserted a Torx bit into the passenger side lock and rotated counter clockwise and locked the trunk lid down and extinguished the light. The button that controls the screen that goes up and down doesn't do anything anymore and she is afraid of trying to close the top in case it stops halfway. I suspect this has been answered elsewhere but I have not found an answer searching the forums but I suspect it is because I don't know what all the parts are actually called. Any help would be appreciated. I have completed most of the maintenance - oil, filters, brakes, tires, batteries, etc. - still have to service the transmission and the coolant. There is a lot to learn for a guy who grew up on American trucks. Thx
2013 Porsche 911 Carrera 4S, 2004 SL55, 2012 Lexus IS250, 2021 Toyota Highlander
Couple of things to check. Check for codes to see if anything shows up. I'm wondering if there's a switch problem not telling the module to go to the next step. Second thing would be the hydraulic fluid. What does the level look like?
Usually that indicates lack of pressure in the final step. You might be low on fluid and you might have an leaking cylinder. First suspect would be the passenger frame lock cylinder since it was the one that didn't work. However, both frame locks, the trunk lift, and the front latch are all on the same hydraulic circuit and any bad seals can be the issue.
As far as the roll bar (with wind screen), it will not operate if the roof is in mid cycle. Even though you latched it, it hasn't completed the cycle. Continue holding the open switch until you see the hardtop open message on the dash.
Yes to all. The fluid was low and by quite a bit. So, I filled it up and finish the open cycle and the roll bar worked. Now for the bad news. Tried to put the top up and there was a tremendous leak pouring hydraulic fluid from the front edge of the hard top. I suspect that most of what I put in came out. I stopped trying close the top and am wondering how do I get to the passenger side cylinder with the top halfway open? I am assuming it is either the cylinder or the line leading to it. The videos I have seen show replacing the cylinder with the top in the closed position. Given the size of the leak I would assume something bad happened when my wife tried to cycle it the last time.
Thx
2013 Porsche 911 Carrera 4S, 2004 SL55, 2012 Lexus IS250, 2021 Toyota Highlander
I've been in that situation before. You've got a 20 year old car with 20 year old hydraulics. It's not uncommon for these to leak or simply give out. There are a couple of companies that can repair the hydraulics on these cars. Cabrioworld and TopHydraulics are two that come to mind. I would suggest, in the meantime, to either put the top up or down manually (there are a few youtube videos that can show you how to do this). I wouldn't recommend to fill the pump up and use the hydraulics. Whatever you chose, you'll need to put the flap in our out and you'll need a diag tool to do so. It's not too bad, but it bit me the first time I encountered this.
Thanks for the quick response. I looked at Top Hydraulics and if you send them all of your cylinders (8 total) they can rebuild them and have them back in a couple of weeks for ~$1150. That doesn't sound that bad actually. They can send you rebuilt one next day for $1500 plus an $800 core charge which you get back when you return your cores. I am not in that big a hurry. I am thinking that as long as I have to do all that work I should just replace them all. Thoughts? I will check out the other place as well.
Thx again.
2013 Porsche 911 Carrera 4S, 2004 SL55, 2012 Lexus IS250, 2021 Toyota Highlander
I sent in my trunk cylinder last year and the process was pretty easy and straightforward. Probably took a bit over a week from purchase to receiving it back.
Yes to all. The fluid was low and by quite a bit. So, I filled it up and finish the open cycle and the roll bar worked. Now for the bad news. Tried to put the top up and there was a tremendous leak pouring hydraulic fluid from the front edge of the hard top. I suspect that most of what I put in came out. I stopped trying close the top and am wondering how do I get to the passenger side cylinder with the top halfway open? I am assuming it is either the cylinder or the line leading to it. The videos I have seen show replacing the cylinder with the top in the closed position. Given the size of the leak I would assume something bad happened when my wife tried to cycle it the last time.
Thx
That fluid probably came from the front roof latch cylinder. It is probably too late. But remove the headliner and stop the leak before hydraulic fluid turns the passenger side upper window weatherstrip wavy.
I took the trunk apart this morning and the only signs of fluid were on the passenger side near the back of the trunk and on the trunk lid. I included pictures. I don't see a cylinder on the trunk lid.
You were right. Saw a slight drip from the manual unlock button cover at the front of the headliner and as I removed the headliner the rest of the missing fluid showed up. Fortunately my wife was ready with the towels and we had put plastic over the seats and doors. The weather stripping on the passenger side window is ruined as you expected. I also have to chase down some of the fasteners at the back of the headliner as the mounting plates broke instead of the lock button coming out. This $10K beauty is rapidly turning into a $15K PITA.
get a rebuilt roof latch cylinder or send in yours first to Convertible Top Cylinder Rebuild Service - (cabriolet hydraulics) with the couplers for the hoses. FILL UP THE FLUID AND YOU SHOULD BE GOOD FOR A WHILE.
That was work. Originally tried to follow the hoses all the way back to the pump but couldn't find where it went through the rear window mechanism so contacted reference above and they pointed to a well-documented guide for "cutting" the hoses and splicing in the rebuilt cylinder. It's on its way to a rebuild. Pray it goes back together easier than it came apart. Have ordered a bunch of plastic fasteners to replace those that fell apart on removal. Am I a heathen if I substitute modern, easily removable fasteners (metal) in lieu of the 3-part plastic ones.
Thx again everyone for the help!
EWB
You were right. Saw a slight drip from the manual unlock button cover at the front of the headliner and as I removed the headliner the rest of the missing fluid showed up. Fortunately my wife was ready with the towels and we had put plastic over the seats and doors. The weather stripping on the passenger side window is ruined as you expected. I also have to chase down some of the fasteners at the back of the headliner as the mounting plates broke instead of the lock button coming out. This $10K beauty is rapidly turning into a $15K PITA.
if you’re not at peace with it becoming at $25k PITA, dump it now lol
Finally, was able to put everything back together and get ready to test only to find that my new (4-month-old) battery was no good. After a few days of proving it to the manufacturer they sent me a new one which I got installed over the weekend. Only two things left to do. The trunk lid flaps aren't retracted and from what I see online there is supposed to be a screen on my Foxwell scanner to retract them, but I can't find it. Second, the passenger side windows molding is all curly from the hydraulic fluid. Is it as simple as drilling out the rivets and replacing with a new molding? Is there a good source for the molding? As always, Thx!
2005 R 230 SL350 (M112 3.7). Sold the 1966 W113 230SL recently
Originally Posted by EWB_TUS
Second, the passenger side windows molding is all curly from the hydraulic fluid. Is it as simple as drilling out the rivets and replacing with a new molding?
God, no. No drilling. The seal is pressed into a metal profile plus there's a butyl sealant. You have to pull things apart, including front and rear rubber end pieces. Mounting the new seal is a pig, so pay attention as you remove the old one and take your time. (Instead of butyl I used a black salt water resistant shipbuilding sealant).
Last edited by Frederick NL; Apr 13, 2026 at 01:25 PM.
USE STAR DIAGNOSTICS TO RETRACT FLAPS. See about 3.5 minutes into video: how to manually close roof: (20) 2004 sl 500 top stuck | Page 2 | Mercedes-Benz Forum shows DAS control units close flaps. Menu screen shots are in German. They say Star Diagnostics instead of DAS or XENTRY which are within Star Diagnostics. Summary: In DAS go to Control Units, Body, Rollbar, Activations, Emergency Operation Activations, Retract Extend Side Covers, Press f3. Or retract flaps using the emergency override described in WIS document.
Above shows all manual roof operation without electrical. Toward the beginning it shows that he removed the toothed gear to manually move flaps. You open the trunk and remove five bolts to remove the gar on a flap.
So, I have discovered that unfortunately, the Foxwell NT-710 scanner does not support the OEM option to retract the trunk flaps. Everything else is in the correct position so at this point I will start it up and push the lever secure the hardtop in the closed state and hope the trunk flaps close. If not, I will disengage the motor and my wife's car becomes a sedan.
I took the trunk lid cover off to expose the motor and mechanism hoping there would be a way to reverse the flaps, but I don't see. Is there a way to do it with the motor? I am assuming the motor is 12 volt DC and that powering it correctly would retract the flaps.
2005 R 230 SL350 (M112 3.7). Sold the 1966 W113 230SL recently
Yes the motor is 12 volt and polarity decides the flap direction. Careful, you'll probably have no automatic stop. An easier access to the motor is the coupling to the rear of the hydraulic pump. In either case, my advice is to disconnect both batteries before you try this, reason being you don't want to the roof controller tot intervene or get upset.
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Convertible hard top stuck in un-locked position
