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1995+ Roadster Soft Top (RST) rear locks in opposite position

17K views 19 replies 9 participants last post by  herb  
#1 ·
I had an issue this weekend when doing a flush of fluid in the RST system. I removed my hardtop and when attempting to raise the soft top, the switch light blinked and nothing happened. The roll bar would go up and down just fine. I did a search here and found some pictures (I believe posted by lynns) that showed the proper position of the rear latches. Turns out one was up (driver side - unlocked position, ready to receive the top post to go down to the locked positon) and one was in the locked position (passenger side - down). Both have a switch that "tells" the controller that everything is okay. When all is good, the top will work. When the two are out of sync, the mechanisms will not work. I manually opened the tonneau cover and attempted to move the locked-down lever up with a screwdriver as others had some luck with. No luck here. I unbolted the latch (three nuts) and pulled it forward. I found that at the back side of the latch, there is a silver tab that is spring loaded. Pull and hold the tab and you can then pry up the latch-lever with a screwdriver. This same tab, when let go, will then lock the latch-lever in the correct place. So when both latches-levers are up, the switchs are closed and everything works as it should. I stowed the top and shut the tonneau cover and pushed the switch and my top came up. Now I could not tell if there was oil on the cylinder leaking or if it was from when I sprayed WD-40 onto all parts just before I checked (mental lapse). I'm not quite sure how the hardtop was released with that cylinder being in the locked down positon and I did not put the top down and up a second time to find out if it would work as I wanted the top up, it was getting toward dinner time and I wanted to jam some on my guitar some, so if my problem isn't solved, I'll report it in another post.
 
#2 · (Edited)
'95+ rear locks

560SEC944,

Thanks for sharing. I will respond only briefly, so this thread can concentrate on wonglf's leaks for now. In the near future, I'll post some more in-depth description of rear lock issues on '95+ models in a separate thread.

The problem you have experienced is not unusual, especially for '95+ models, and it mostly happens after folks remove their hard tops. It is possible to accidentally push a rear lock down when the ignition is off, and there the confusion starts. There's a bit of a design flaw in the '95+ system, where the rear locks do not have a limit switch for the open position, only for the closed position. That makes the controller rely more on memory, and an accidentally closed lock on one side can confuse the controller... The '95+ controller will freeze operation a little more readily than the older ones, on account of its different programming. Your controller was reading that the front locks were already open, but one rear lock was still/already closed. That makes the controller stop everything on account of illogical readout.

The levers you have found when pulling out the locks are the emergency release and lock levers. They are still accessible from the trunk (although your manual ignores them), with a 10-mm wrench, once you push the front trunk panel aside (after removing some three or four clips).

More later,

-Klaus

klaus@tophydraulicsinc.com
 
#3 ·
Mitch,

since you've done the drill many times already, and the other locks seem to work manually, this particular one may just have a mechanical problem. You may have to take out the lock and examine it for bent or broken parts, or obstructions inside. Here are the removal instructions:

http://tophydraulicsinc.com/R129 Rear Locking Cylinder Removal.pdf

It may also be that your cylinder has been exposed to additives in the hydraulic fluid, which made the seal around the moving plunger swell up and stick to the cylinder wall. However, in that case, the other cylinders would be fairly hard to move as well.

Hope this helps, and please let us know what you find. Once we have this problem solved, let's move on to getting your roof fully operational!

-Klaus

klaus@tophydraulicsinc.com
Klaus, I found these instructions most helpful this past weekend when I fixed my issue with one latch being in the locked position and I thank you for them. The only thing I could add is that I was able to remove the latch without removing the C-clip on the tonneau top piston. I just closed the tonneau top about 1/2 way and then I was easily able to get a socket on the nut. Once all three nuts were off, the latch was manuvered around the studs and the tonneau top piston. Now will the pictured wrench really work with the newer latches on the emergency tab? The newer ones are vertical, not horizontal. - Don
 
#4 ·
Unlatching '95+ rear locks

Don (560SEC944),

congrats on getting your rear lock released! Your method may have been as fast as removing part of the panel in the trunk, but it works only for those who already have the tonneau cover open, of course. Also, good move on partially closing the tonneau cover to get better access to the nuts that are holding the rear locks - I left that trick out of the instructions to keep them simple, since most folks remove tonneau cover lift cylinders and rear locks at the same time. Their seals generally fail at about the same time... (Well, I could also start raving now that it's usually time to do all seals at once, once the rear cylinders fail, but that's totally off topic. Statistically speaking, on average there are less than three decent seals left in a set of 11 or 12 cylinders, once people notice leaks in the rear and send us the whole set for upgrades.)

I have posted instructions on releasing and latching the rear locks on '95+ models a few times before, but they get lost easily in all these posts on BenzWorld. Thus, I'm attaching a couple of pictures again below, that show how to access the locks through the trunk.

You are asking whether the soft top tool can be used to do the job. Well, I've done it with that tool, but it was a bit frustrating on the right side, with all the lines from the fuel tank. A regular, angled 10-mm open wrench is easier to use. The second picture below actually shows the soft top tool being used. Moving the lever up unlocks the rear lock. There is not much leverage to manually latch the rear locks with this method, but it can be done (pushing the lever down when the lock is already pretty far engaged from pushing the top down into it).

-Klaus

klaus@tophydraulicsinc.com
 

Attachments

#15 ·
Thanks from a noob 129 owner

Don (560SEC944),

congrats on getting your rear lock released! Your method may have been as fast as removing part of the panel in the trunk, but it works only for those who already have the tonneau cover open, of course. Also, good move on partially closing the tonneau cover to get better access to the nuts that are holding the rear locks - I left that trick out of the instructions to keep them simple, since most folks remove tonneau cover lift cylinders and rear locks at the same time. Their seals generally fail at about the same time... (Well, I could also start raving now that it's usually time to do all seals at once, once the rear cylinders fail, but that's totally off topic. Statistically speaking, on average there are less than three decent seals left in a set of 11 or 12 cylinders, once people notice leaks in the rear and send us the whole set for upgrades.)

I have posted instructions on releasing and latching the rear locks on '95+ models a few times before, but they get lost easily in all these posts on BenzWorld. Thus, I'm attaching a couple of pictures again below, that show how to access the locks through the trunk.

You are asking whether the soft top tool can be used to do the job. Well, I've done it with that tool, but it was a bit frustrating on the right side, with all the lines from the fuel tank. A regular, angled 10-mm open wrench is easier to use. The second picture below actually shows the soft top tool being used. Moving the lever up unlocks the rear lock. There is not much leverage to manually latch the rear locks with this method, but it can be done (pushing the lever down when the lock is already pretty far engaged from pushing the top down into it).

-Klaus

klaus@tophydraulicsinc.com
This is one of the few times I did a search on a problem, and was able to get a solution that works. Sometimes it's even hard to find anything remotely to to point.

Anyway, this thread and your pictures using the tool were key to resolving the same problem. When removing my Pano yesterday everything went well untill I tried the top mechanism. Upon close inspection, I spotted the two rear locks in different positions, and with that clue went searching for this thread.

Was realy simple once the concept was understood and the picture with the tool in the up position did the trick.

After that right rear lock mechanism opened per your instructions, the top works fine now.

I did find some small pieces of cardboard in that lock, cleaned it out, and gave all the locks I could see a light spray of lubricant.

So thanks for the tutorial Klaus ... when the time comes for seals, you'll get my business.. Regards...O
 
#5 · (Edited)
I removed my hardtop and when attempting to raise the soft top, the switch light blinked and nothing happened. Turns out one was up (driver side - unlocked position, ready to receive the top post to go down to the locked positon) and one was in the locked position (passenger side - down). Both have a switch that "tells" the controller that everything is okay. When all is good, the top will work. When the two are out of sync, the mechanisms will not work.
This is not an uncommon problem and has happened to me a couple of times after removing the hard top (HT). I'm not sure that there is any simple answer as to why this happens on occassion but it's like losing a sock during the wash/dry cycle.

But what I have found is that it's very important when removing the HT to follow through with the cycle and make sure you don't take your finger off of the Red button until you know that the top has been released. Then manually take the HT off of the car and look into both of the rear hydraulic cylinder holes and make sure that both latches look like they are in the open position. Because if they are not you will experience what '560sec944' had happen.

It's my guess that everything is back in working order based on what I read above. So if I were you I would try your soft top several times just to make sure.

BTW, in the future let's try not to combine seperate problems into one Thread as though all RST problems are linked. FWIW, the RST is somewhat complex in it's design because we have an electronic controller, limit switches, lock latches, hydraulic pump, and hydraulic cylinder seal issues that may or maynot be related when they exhibit themselves (especially during what I call Spring fever). Most of which have been discussed and answered many times over and if you would like to become more familiar with this system feel free to read the last two Threads in the 4th Blue Sticky at the top of the forum and may I also suggest that you pay close attention to our former RST Guru 'bobterry99'. He was a major contributor to this forum until he bought an R230 and got busy with the other issues of life.
 
#6 ·
Why it happens...

Lynn,

thanks for separating this section from the original thread. You are right about needing to complete the release cycle for the hard top. The following is the reason for the locks ending up in opposite positions and freezing the RST operation.

All rear locks have a positive lock for the open position. That's where the locks end up after you completed the hard top release cycle (and the soft top release cycle for that matter). By positive lock, I mean that the hydraulic cylinders will not be able to pull the lock into the closed position, unless the prongs from the top have entered the locks already and are pushing on the locking mechanism. This is supposed to insure that the locks are always open when they are supposed to receive either the hard top or the soft top via its prongs. The '95+ controllers rely on this positive lock and do not have a readout for the fully open position, as opposed to the '90-'94 controllers. This works well for the front locks and for the tonneau cover locks, but it can fail on the rear locks with the flexible prongs from the top and the wiggle room available.

If you don't complete the release cycle, as has happened to you and to 560sec944, the hard top (or soft top) can end up resting on one latch already locked in the open position, whereas the other one had already released from the locked down position, but not yet reached the positive open lock position. At that point, it is possible to pull the top out of the lock without it clicking into the positive open latch position. This usually happens only with the hard top, because people wiggle it around some, while they are balancing the weight of the hard top and worrying about scratching things up. The soft top moves symmetrically in its linkage, so it's not common that the rear prong can slip out of the rear lock without pulling it into the positive open latch position, even during manual operation.

Now that the prong has slipped through the not fully opened lock, you can accidentally push the partially open rear lock into the locked position by fully resting the rear corner of the hard top (or soft top) on it when the ignition is off. Again, that's where the system freezes because it is illogical in the system's cycle that a rear lock is in the latched down position while the front locks are still open.

Hope this makes sense,

-Klaus

klaus@tophydraulicsinc.com
 
#7 · (Edited)
Lynns, sorry to pollute the post and thanks for the correction.
Klaus, as for your picture, I saw that before, but this is not what the back of my latch looked like (albeit that I did not look at it from the trunk prospective when bolted to the tonneau/softtop compartment). Here is a link to one on ebay that is for sale and that looks like the one I have.

New GENUINE Mercedes Convertible Top Latch BRAND NEW | eBay

In the fifth picture, you can see the "silver tang" between the two black "rails" on the far left. This is what I pulled up and was then able to move the lever. This the the locking release mechanism as shown in you picture that you have the wrench on. I do not think the wrench will go on this as it it vertical, not horizontal as the one shown in your picture. Am I wrong?
 
#8 ·
same lock

Klaus, as for your picture, I saw that before, but this is not what the back of my latch looked like (albeit that I did not look at it from the trunk prospective when bolted to the tonneau/softtop compartment). Here is a link to one on ebay that is for sale and that looks like the one I have.

New GENUINE Mercedes Convertible Top Latch BRAND NEW | eBay

In the fifth picture, you can see the "silver tang" between the two black "rails" on the far left. This is what I pulled up and was then able to move the lever. This the the locking release mechanism as shown in you picture that you have the wrench on. I do not think the wrench will go on this as it it vertical, not horizontal as the one shown in your picture. Am I wrong?
560sec944,

it's the same lock, but my picture shows the release lever already in the "up" position. I should have clarified that. To get the release lever into that position with the huge, straight soft top tool, there are some serious, evasive maneuvers needed around the tank filler pipe. Keep in mind that MB wants this to be a shop-only procedure, yet it's easy to do once you know how... They are not providing the access holes in the trunk, as they have in '90-'94 models, so the biggest hurdle is in removing at least two of the upholstery clips/rivets in order to pull back the corner of the front trunk panel.

Again, it's much easier to do with a smaller, angled wrench. In your case, where there was no tension on the lock via a top pulling on it, it would have been possible to pull the lever up with a finger. :)

-Klaus

klaus@tophydraulicsinc.com
 
#10 ·
not this time...

Don,

leaking cylinders are the cause for many problems, but not likely for this particular one.

It is always the retracting movement of the cylinder that is compromised first by leaking seals, unless your pump is already completely out of fluid. I'm sure the latter is not the case for you. Completing the unlocking cycle takes so little pressure in the rear, that it was not a leaking seal (leading to lack of fluid in the pump) causing the problem, but it was the chain of events I described in the previous post.

-Klaus

klaus@tophydraulicsinc.com
 
#11 ·
Thanks Klaus - I feel better - and I will do as lynns suggest - acuate the top up and down several times - I still need to finish out the flushing process that I originally started to do. I think my wife was happy to stop the process before it got started, as it has been approaching 100 degrees here in the Dallas area, so she prefers the inside of the cool house to holding a soft top button while sitting in the car outside ;-).
I will say this, I was worried before I did any of this that working/sort out problems on the soft top would be a nightmare. After doing it, actually studing the mechanisms and reading yours and lynns posts, I can go to sleep and have pleasant dreams! I truely appreciate this forum and the intellegent, experienced advise shared by good members/moderators like Klaus and lynns.

Now I have'nt mentioned that I recently bought a Cadillac SRX, but that will be covered in a different post...
 
#12 ·
REPLACING SEAL KITS FOR SOFT TOP CYLINDERS

GENTLEMEN: I HAVE READ MANY OF YOUR THREADS CONCERNING THIS TOPIC. ALL OF WHICH WERE VERY INFORMATIVE. SINCE I HAD DECIDED TO DO ALL OFTHE CYLINDERS AND THE MAIN LIFT CYLINDERS BEING A REAL TASK GETTING THE THREADED BOLT OUT THROUGH THE OPENING IN THE PILLAR POST AND THE PROCESS OF REMOVING THE LOCK CYLINDER ON THE RH SIDE WITHOUT CAUSING DAMAGE TO IT IN THE PROCESS I FOUND IT WAS MUCH SIMPLER TRO REMOVE THE COMPLETE TOP ASSY. WHICH TOOK ONLY 45 MINUTES, I HAVN'T INSTALLED IT YET SINCE I AM WAITING FOR THE SEAL KITS. I SHOULD ALSO MENTION THAT I DID BUY THE SEALS FOR THE FRONT LOCK CYLS FROM A SEAL SUPPLY SHOP IN BANGKOK FOR A ONLY FEW DOLLARS.($8 FOR BOTH CYLS) I DON'T HAVE THE TIME TO GO AND SEARCH FOR THE OTHER SEALS SINCE IAM 700 KMS FROM BKK, HOWEVER WHEN I DO REPLACE ALL OF THEM I WILL GET AROUND TO LOOKING FOR THEM. HAVING THE OLD SEALS MAKES IT EASIER TO FIND ESPECIALLY SINCE MOST JOBBER PARTS SHOPS OVER HERE DON'T USED PART NUMBERS WHEN SUPPLYING PARTS. YOU SHOW A SAMPLE AND THEY WILL FIND THE PART. YOU MAY TRY NOK SEAL WEB SIGHT AND DOWNLOAD THEIR CATELOGS FOR SEALS. THERE IS A ENORMOUS AMOUNT OF INFO REGARDING ALL TYPES OF CYLINDER PISTON, ROD AND SEALING RINGS FOR HYD SYSTEMS.
 
#13 ·
seals are off topic here

LCAN,

We appreciate your good intention. I understand that you are in the automotive repair business. Two requests: would you please NOT SCREAM in your posts, and next time post seal related issues in a previous thread that actually covers seals?

FYI, we supply the seals, and in longer lasting quality than anything off the shelf, but I don't want to hijack the subject here by elaborating on it any more. See http://www.benzworld.org/forums/r129-sl-class/1592184-soft-top-closing-problem.html for a good reason why we don't like to sell the seals...

You mentioned removing the top to get to the "right lock cylinder" more easily without damaging it. I assume that you are referring to the left bow extension cylinder. I personally don't find that removing the top will save you any time, but others may disagree. I recall a much too long debate about that between our esteemed members chriswufgator and bobterry...

klaus@tophydraulicsinc.com
 
#14 ·
Well, once again Klaus was right - I bought a 2 X 4 sheet of plywood this weekend and found that it would not realistically fit in the passenger side nor the trunk. I opened the top and found that no way would it fit behind the seats. Closed top - everything worked like a charm. Took plywood back into store. Came back with SRX, loaded and took home.
 
#17 · (Edited)
Slightly different problem with locking down...

Although there has been much explained about the misbehaving lock/latch.. Mine seem to be a bit different.. Let me explain.

I know the hydraulic seals are on their way out, as although the soft top works fine up/down.. The soft top now comes down on the front window latches pretty fast. Ie once gravity takes over.. The cylinders are not holding the top and bringing it down slowly. Nor can the top be stopped in the vertical position, as it sinks down into the trunk.

This leads me to my current problem.. When I removed the top this summer it was to my recollection seated properly.

Now when putting it on it seem to lock down ok and you cannot move or lift it manually.

There is however a 1/4 inch gap at the rear between the bottom leading edge of the hard top and the body oft the car.

If the hard top switch is held the top is pulled down hard against the body with only a few millimeters gap. This is how I think it is supposed to be.

The minute you let go of the switch it pops up to a quarter inch gap. The top is still weather sealed at the rear but I'm not sure if it actually pulled down with sufficient force to seal it properly.

As I have had an issue with a few drops of water coming in through the far left passenger side near the top of the front window pillar.

I suspect the hard top although "locked in" .. It does not pull it down hard enough to make a perfect seal due to hydraulics leaking past internally in the cylinders, so they cannot maintain the pressure holding the entire top down hard enough to make the weather seals work the way they should.

Unfortunately it seems as my only option is to reseal the hydraulics.. Not sure if you accept work from New Zealand Klaus :)
 
#18 ·
top coming down fast, gap in the rear, rebuild work for New Zealand

ROAMERNZ,

thanks for your detailed description. I will paste in some brief responses below...

The soft top now comes down on the front window latches pretty fast. Ie once gravity takes over.. The cylinders are not holding the top and bringing it down slowly. Nor can the top be stopped in the vertical position, as it sinks down into the trunk.
The most straightforward assumption would be that you have a bunch of air in your hydraulic fluid. The air gets compressed as the pump lifts up the top, and then makes it spring forward when there is less load.

The reason for air in your fluid would be a low fluid level, and the reason for that would be a hydraulic leak. Thus, you are likely right in saying that your seals are on their way out...

This leads me to my current problem.. When I removed the top this summer it was to my recollection seated properly.

Now when putting it on it seem to lock down ok and you cannot move or lift it manually.

There is however a 1/4 inch gap at the rear between the bottom leading edge of the hard top and the body oft the car.

If the hard top switch is held the top is pulled down hard against the body with only a few millimeters gap. This is how I think it is supposed to be.

The minute you let go of the switch it pops up to a quarter inch gap. The top is still weather sealed at the rear but I'm not sure if it actually pulled down with sufficient force to seal it properly.
There is some play in the rear locks, meaning the hydraulic system will indeed pull them down a bit past their resting position; this probably explains your finding. As the weatherstripping in the rear ages and gets softer, the additional pulling you described will be more noticeable. If you find the rear not to be water tight any more, you can adjust the rear locks: loosen the three hex nuts that hold them in place, and slide down the locks a few millimeters. To pull down the front tighter, you loosen the prongs on the top with a star wrench and slide them back a little. Mark the initial position, so that you can always go back without much trouble.[/QUOTE]

Unfortunately it seems as my only option is to reseal the hydraulics.. Not sure if you accept work from New Zealand Klaus :)
We work with folks "down under" all the time - would be delighted to be of assistance. Shipping a full set of cylinders with all latches attached costs only $80 via Express Mail, which is a one-week service. You have the option of sending in your cylinders first for us to rebuild, or take the "luxurious" option of having us ship a set from stock... ;)

Klaus

klaus@tophydraulicsinc.com
Top Hydraulics | Rebuilt Convertible Top Hydraulic Cylinders - Top Hydraulics, Inc
 
#19 ·
I too had a problem with my rear lock being out of synch after removing the hardtop and the softtop still stowed (and yes, it's possible I released the red button a fraction too soon). In my case the left (driver side) rear lock was unlocked and ready to receive, while the right side was locked and blocking any possible prong from being inserted. The red button just flashed when I tried to use it to clear the problem. Windows and roll bar worked perfectly.

Following the instructions and pictures above from Klaus totally fixed the problem. The truck panel was easy to move out of the way and I was able to identify the release lever. Mine was horizontal, seemed like a neutral position. I was able to use a normal 10mm wrench to rotate it up slightly (very little resisting pressure), and while holding it up, moved the lock up toward the full unlock position (I had manually opened the rear cover for the soft top iaw intructions in the Owner's Manual so I could see and get at the lock from the other side). Finally, I used the wrench to rotate the locking lever downward while I pushed the lock higher and everything clicked into place. I then released the locking lever and it returned to its horizontal neutral position. This happened so quickly and easily that I hope I"m recalling the sequence correctly.

Anyway, everything worked perfectly after that. I've opened and closed the soft top a couple of times since and no problems. Thank you, Klaus, for your help...you saved the day!
 
#20 ·
As usual, Klaus' advice is right on.
Once again, I let go of the control button too soon locking up the controller, so the only solution I know is to put the hard top back on, then remove it. A pain.
Prevention is far more efficient and only takes a moment when we age-impaired remember.

Just to clarify, when you look in the latch hole and see a front to back black bar, the latch is open, when the hole looks empty, it's closed.
Doesn't seem right to me, but I do know that Klaus provides accurate info, and that is what he told me. Thank you, Klaus, Vielen dank!