SL-Class (R129) 1990-2002: SL 280, SL 300, SL 320, SL 500, SL 600, SL 60 AMG

SL/R129: Rear part of the convertible top will not competely close

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Old Mar 2, 2014 | 08:49 PM
  #1  
Evan Z's Avatar
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1996 SL500
Rear part of the convertible top will not competely close

Hey again... I have checked the forum, but can't find a similar question, so here goes...

My convertible top works fine, with the exception of the rear, which has slowly developed an issue over the last year. When raising the soft-top, the rear will not quite lock into place and stay flush with the body (this is the part of the top that runs along the body near the trunk area).

Watching the soft-top in operation, it appears as if the convertible mechanism is pulling the rear section into place as is normal, but after the cycle has completed the trailing edge lifts up a slight amount (about a millimeter or so). This has the effect of triggering the top-warning system once the car is driven and hits a bump, and when I examine the top, it is clear that the rear-most is definitely not flush with the body as it should be... This problem started gradually, and does not seem to be related to temperature, frequency of use, or any other variable.

When securing the aluminum hard-top, the issue repeats itself. It seems as if the hydraulic cylinders which are used to secure the rear area are simply not providing the movement they should be, and yet there is no apparent leakage, odd noises, etc.

I am considering pulling out these rear cylinders and having them rebuilt (I'm supposing that there is one for each side), but would like to gather some opinions first. Any suggestions or comments from the convertible-top gurus? Whatever help is available would be greatly appreciated. Thanks!
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Old Mar 2, 2014 | 09:51 PM
  #2  
cliffyk's Avatar
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From: Saint Augustine, FL
1998 SL500
The first thing to do is check the fluid level in the hydraulic pump's reservoir...
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Old Mar 2, 2014 | 11:34 PM
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Evan Z's Avatar
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1996 SL500
Thanks... yup, I've checked the reservoir, fuses, and all of the usual suspects. No issues on that front.
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Old Mar 3, 2014 | 12:32 PM
  #4  
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From: On the beautiful Oregon Coast
03 SL Kleemann, 97 SL320 pano top, 95 Lorinser E320 Cabrio, Ferrari 360, Tesla X
Evan Z,

where are you located?

It is normal for the rear of the top to go up about a millimeter after the rear locking cylinders 1298002172 got the rear locks 1298001174 and 1298001774 in your car past the dead spot. The real issue here seems to be that the chime goes off after you drive over a bump, right?

Originally Posted by Evan Z
Watching the soft-top in operation, it appears as if the convertible mechanism is pulling the rear section into place as is normal, but after the cycle has completed the trailing edge lifts up a slight amount (about a millimeter or so). This has the effect of triggering the top-warning system once the car is driven and hits a bump, and when I examine the top, it is clear that the rear-most is definitely not flush with the body as it should be... This problem started gradually, and does not seem to be related to temperature, frequency of use, or any other variable.
If you want the rear of the top to be more flush with the body, then you can move the rear locks down a little. This is not an adjustment one normally has to make.

The cause for your top warning system (the chime) going off after you went over a bump, is very likely in the micro switches on one of the front locks 1298000774 and 1298000874. This can happen after the weatherstripping in the front ages, and the front locks develop some play in them. It also happens frequently after people replace their front lock cylinders 1298001672 and accidentally bump the metal lever that pushes onto the lock's micro switch.

Here is how to check which one of the front lock micro switches needs adjustment in your case, where the red light stays on after the top has closed all the way:

Put the soft top tool (6-mm Allen wrench) into the front lock on one side, through the hole in front of the visor. Turn the wrench such that it locks even farther, taking the play out of the lock. That direction is different on the opposite sides, by the way. It is counter-clockwise on the left side and clockwise on the right side. If the red light goes out, then you have found the lock that needs adjustment.

Try the same on the other side if necessary.

(You might get away with only adjusting the prongs on your soft top, following the instructions in http://www.benzworld.org/forums/r129...djustment.html, but that would likely be only a temporary fix and eventually result in the chime going off every time you drive over a bump.)

Adjustment procedure:

Note that you need to re-install the windshield header panel before the top will operate on model years '95+. Also, be careful not to pull on the wires of the magnetic sensor that is mounted in the windshield header panel on model years '95+. See page 3 of http://www.tophydraulicsinc.com/R129...%20Removal.pdf.

The micro switch on the front lock(s) gets pushed DOWN by a lever when the lock is OPEN. There is some reverse logic involved here, so take it slow and read very carefully.

As the lock receives the soft top in it and locks, the small lever that is pushing on the switch releases just enough for the switch to click open once the lock itself is in closed position. If the lever has been bumped or bent when the front locks were installed, or if the locks have developed play over the years, then oftentimes the lever is not pushing down far enough by the time the lock is in the final (resting) locked position. This resting position can be different from the locked position without the top being latched down by the lock.

In your case, you probably have to bend that lever up just a tiny bit (1 mm or 1/32 inch). This adjustment can be made without removing the lock. Remove the windshield header panel and adjust the lever above the micro switch until it barely touches the switch when the lock is closed. Note the play in the lock - you need to recreate the position the lock would be in if the soft top was closed and pulling up on the lock. This is shown in the third photo with the caption "Front lock in real life with the top pulling". Ideally, the boot of the switch will just start bulging when the lock is in the "real life closed position".







I hope this helps. Please let us know what you find, and please also check if you find ANY hydraulic fluid around or under the front lock cylinders.

Klaus

www.tophydraulicsinc.com

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Old Mar 4, 2014 | 01:11 AM
  #5  
Evan Z's Avatar
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1996 SL500
Thanks very much! I'm located in Colorado. I'll investigate and update this thread when I have some news.

Last edited by Evan Z; Mar 4, 2014 at 01:14 AM.
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