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Just purchased 2003 SL500. Only 2 previous owners, 27k miles. In checking before purchasing, I knew there was never ending issues with top failure. However, the owner has just replaced the hydraulic motor 2 years ago, so I thought maybe I was safe. Went to retract the top today for the 2nd time. Trunk went up about 2/3 rds. Tried lowering, and it came down within an 1" of fully closed. Researched dozens of You Tube videos, but not able to resolve issue. I'm a Corvette owner and that forum has so much knowledge, it's saved me many times. I trust the MB forum is the same. My nearest dealer is about 1 hr. away, so would certainly love the get the trunk lowered and locked down. If, I'm able to do that, would love to be able to do some basic troubleshooting in the hopes its fairly simple. I've worked on my own cars since a teenager, but this is the first foreign car I've owned, so unfamiliar with German technology. Thanks in advance for any help.
Stalling at that point is usually low pressure. Most common cause is low fluid, which also means that you have a leaking cylinder. The pump probably accounts for 5% of issues, so plan on several cylinder replacements in your future.
Also, you can latch the frame locks manually. There is a plastic plug on each side of the trunk that you remove and rotate the latch with the Allen key in the toolkit. That will pull the trunk lid down so it is safe to drive.
Thanks for the responses. Admittedly not knowing the system, my initial guess was a hydraulic issue since I can hear the pump motor running trying to raise/lower the top. My issue now is how to get the trunk fully lowered to inspect the pump. Thanks MikeJ65 for your suggestion, but with the trunk in its current position(see pic attached)I have no access to rotate the latch. Also, took kit is in the trunk. This is where I'm stuck-cannot access the trunk. If I could access the trunk, one other thought occurred to me. I would check the bleed screw on the pump to ensure I had not somehow gotten loose. Realizing the chances of that being the culprit is slim/none
2013 Porsche 911 Carrera 4S, 2004 SL55, 2012 Lexus IS250, 2021 Toyota Highlander
My guess is low pressure as well. Get familiar with putting the trunk in service mode. You can still use the key to open the trunk. Check out the video below.
Learning a little as I go. Didn't realize I needed to turn the manual key counter clockwise to enter service mode! Once open found the hydraulic reservoir empty. No sign of leakage in the trunk area. Just prior to my purchasing the car last month, previous owner had the car serviced. Looking at the work order, they added fluid, bled the system and checked for leaks. Obviously there is a major leak. Two questions I have: 1. Does the hydraulic system service other components, ie, ABC or other systems? 2. No obvious evidence of leaking fluid in the interior. I don't want to randomly start removing interior panels, so can someone suggest areas I could check for leaks, such as hydraulic fittings, cylinders, etc If just a loose fitting somewhere and I could tighten it up, would be great. If not, will try to make an appointment with MB dealer about an hour away.
Now that I have the trunk in service mode, have seen several videos explaining how to manually close so it can at least be driven.
Thanks for any suggestions.
Learning a little as I go. Didn't realize I needed to turn the manual key counter clockwise to enter service mode! Once open found the hydraulic reservoir empty. No sign of leakage in the trunk area. Just prior to my purchasing the car last month, previous owner had the car serviced. Looking at the work order, they added fluid, bled the system and checked for leaks. Obviously there is a major leak. Two questions I have: 1. Does the hydraulic system service other components, ie, ABC or other systems? 2. No obvious evidence of leaking fluid in the interior. I don't want to randomly start removing interior panels, so can someone suggest areas I could check for leaks, such as hydraulic fittings, cylinders, etc If just a loose fitting somewhere and I could tighten it up, would be great. If not, will try to make an appointment with MB dealer about an hour away.
Now that I have the trunk in service mode, have seen several videos explaining how to manually close so it can at least be driven.
Thanks for any suggestions.
The front roof latch is usually the first to leak. You can remove the headliner. It may be full of fluid. You can touch any cylinder with your bare finger, if it is wet, cylinder leaks.
The roof hydraulic pump only feeds the 11 I think roof and rollbar cylinders. The ABC/suspension is fed by a tandem pump under the hood... tandem because it feeds power steering too.
I have a leak in the cylinder which activates the wind screen/rollbar. Haven't fixed it yet because its a pain to get to and not that important to me.
As mentioned, many members here found that the front roof latch was leaking. In a recent post, a member reported something like a pint of fluid up there which almost made a big mess when he dropped the headliner; fortunately he was ready for it.
I have verified the 5 cylinders I can access via the trunk are not leaking. I am waiting on MB hydraulic oil so I can lower the top and check the 4 cylinders behind the cockpit plus the cylinders for the roll bar. I have sneaky suspicion the culprit is a roll bar cylinder. Learning more everyday about the finicky SL500. First foreign car I’ve ever owned and first used car since early 70’s. I own a Corvette HTC, so wondering what possessed me to buy another 2 seater HTC. Almost forgot-WIFE always wanted a MB! Tiring of her Lincoln Suv
If you don't see any obvious leaks, then I'm confident that adding fluid will let you lower and raise the top at least a few times.
Adding fluid is a pain as it can only be added very slowly. I use a plastic syringe after pouring fluid into e.g. a clean jam jar. (I actually keep everything in the trunk in case I ever have to refill on the road.)
You will lose patience before its full, so only fill half way. Then mark or picture the level and experiment to see if the level goes down when you run the top down and back up. I notice loss when I run the rollbar up and down; hence I know that is leaking.
There is a lot of help available on this forum for these cars. Obviously some of us really like them. Just ask.
Your SL sure is a different car from your C8 Corvette and makes a completely different "statement".
Keep us posted on your progress or lack of it.
If you don't see any obvious leaks, then I'm confident that adding fluid will let you lower and raise the top at least a few times.
Adding fluid is a pain as it can only be added very slowly. I use a plastic syringe after pouring fluid into e.g. a clean jam jar. (I actually keep everything in the trunk in case I ever have to refill on the road.)
You will lose patience before its full, so only fill half way. Then mark or picture the level and experiment to see if the level goes down when you run the top down and back up. I notice loss when I run the rollbar up and down; hence I know that is leaking.
There is a lot of help available on this forum for these cars. Obviously some of us really like them. Just ask.
Your SL sure is a different car from your C8 Corvette and makes a completely different "statement".
Keep us posted on your progress or lack of it.
Thanks for your response. My plan is just as you suggested. My hydraulic fluid should be here today. As there. Is no MB dealer close by, I ordered from Amazon. Does the system need to be “bled” after adding fluid? My pump/motor is a replacement motor with only 1 screw. I know OEM pump has 2 screws-one for bleeding pressure and one for filling.
I experienced a similar issue that you describe, the boot deck lid failing to completely close. My issue was an internal leak within the right tubular frame lock cylinder. Hydraulic pressure was leaking internally past the seal on the piston. An easy way to diagnose it is to touch it after you try to operate it. It will get warm if it has an internal leak.
Thanks for your response. My plan is just as you suggested. My hydraulic fluid should be here today. As there. Is no MB dealer close by, I ordered from Amazon. Does the system need to be “bled” after adding fluid? My pump/motor is a replacement motor with only 1 screw. I know OEM pump has 2 screws-one for bleeding pressure and one for filling.
I have not found the system to need bleeding after adding fluid.
My pump unit has 2 screws and I have marked the one to remove for filling. Didn't know the other was a bleed screw; always good to learn something new.
Hi I am new to the forum and have exactly the same issue as described here happen to me yesterday. Meaning I am in the situation the trunk is stuck 2”. Yesterday I wanted to open the roof and only the trunk went to its vertical opening state but the roof did not move. I then tried to close the trunk and it went down to 2” state and then everything stopped working. There is no more sound when I try to open the the trunk via the roof switch. Note that the safety bar button on the switch also did not work. I checked a few fuses behind the passenger side nothing bad. I am not mechanic but reasonably handy so willing to go down to do things. The trunk release worked so I have it now up and have access to the trunk.
Where do I check the fluid, sorry for my ignorance, and where do I buy it. Also I read here how to put it back in its state the trunk the 2” issue, please guide me on how to do that.
Appreciate your response as its time for me to get my hands in my baby that I want to keep forever.
UPDATE - using the Allen key I got the trunk back in position, and after starting I heard the trunk lock in place. Unfortunately I keep seeing the message that the roof is in operation going down and the roof switch and the rear trunk via my regular key continue not to work.
Here is a picture of the unit, does the fluid sit in the white portion, that looks really empty?
If so please guide me what I need to purchase and where to inject, I read @mrvedit to use a syringe.
UPDATE - using the Allen key I got the trunk back in position, and after starting I heard the trunk lock in place. Unfortunately I keep seeing the message that the roof is in operation going down and the roof switch and the rear trunk via my regular key continue not to work.
Here is a picture of the unit, does the fluid sit in the white portion, that looks really empty?
If so please guide me what I need to purchase and where to inject, I read @mrvedit to use a syringe.
Your pump is different than on my 2003. On mine you remove the screw with the female allen key hole on top of the pump to fill fluid. There are indicators with triangles pointing up and down around lines on the end of the white plastic reservoir cylinder to indicate fill level. Ebay has some hydraulic fluid injector needles and probably tubes/hoses for Mercedes convertible top.
On Amazon search for "Plastic Syringe". I've been using a 10mL syringe, but 20mL might work faster.
My 2004 pump is also different, but likely the brass colored screw covers the fill port.
Thank you, read some more forum treads on this seems my pump has an opening on the top of the white part, going to buy the fluid and then this weekend on it. Will let you all know. So happy to have found this forum.
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