Rear of soft top latches and releases or does not go down all the way



Steve,

welcome to the forum! Thanks for your detailed description of the problem. Most shops would not know what to do with this case. A large number of shops would tell you to get a new soft top controller. Those shops with Star Diagnosis would eventually point at the front locks. Almost any shop would tell you to replace the front locks, because they don't know about the ultimately simple adjustment procedure below.

The key to the description is, combined with the new canvas, that the soft top will not close all the way - it reverses its closing cycle right after or shortly before the rear locks are fully latched. One of the locks does not give the controller the signal that it is fully locked, and that is what makes the chime go off. If a front lock signals that it is not locked while the canvas is going down in the rear, then the controller will reverse the closing of the rear bow until the front lock gives the proper signal.

Almost certainly, the problem lies in the micro switch(es) on one or both front lock cylinders needing adjustment. The new canvas is tighter than the old one, and it pulls the roof up a bit more in the locked front latches. The same thing would happen if folks replaced their front lock cylinders 1298001672 and accidentally bumped the lever on the front lock that triggers the micro switch.

Here is how to check whether it is one of those micro switches needing adjustment, and which one:

After the top has locked in the front, 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. Holding the wrench in the far locking position, push the soft top button forward and check whether the top now fully closes in the rear with the windows going up afterwards.

Try the same on the other side.

If you find that holding the wrench on one side does the trick, then that switch needs adjustment. I will explain the procedure below and include some pics that should illustrate what I'm talking about. Once you know how to do it, it's quite simple!

(You might get away with only adjusting the prongs on your soft top, following the instructions in http://www.benzworld.org/forums/r129-sl-class/1602807-soft-top-front-lock-adjustment.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.)

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 Front Locking Cylinder Removal.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".

Hope this helps, and please let us know what you find,

Klaus

Top Hydraulics | Rebuilt and Upgraded Convertible Top Cylinders, Pumps, Hydraulic Lines - Top Hydraulics, Inc

 

Steve,

welcome to the forum! Thanks for your detailed description of the problem. Most shops would not know what to do with this case. A large number of shops would tell you to get a new soft top controller. Those shops with Star Diagnosis would eventually point at the front locks. Almost any shop would tell you to replace the front locks, because they don't know about the ultimately simple adjustment procedure below.

The key to the description is, combined with the new canvas, that the soft top will not close all the way - it reverses its closing cycle right after or shortly before the rear locks are fully latched. One of the locks does not give the controller the signal that it is fully locked, and that is what makes the chime go off. If a front lock signals that it is not locked while the canvas is going down in the rear, then the controller will reverse the closing of the rear bow until the front lock gives the proper signal.

Almost certainly, the problem lies in the micro switch(es) on one or both front lock cylinders needing adjustment. The new canvas is tighter than the old one, and it pulls the roof up a bit more in the locked front latches. The same thing would happen if folks replaced their front lock cylinders 1298001672 and accidentally bumped the lever on the front lock that triggers the micro switch.

Here is how to check whether it is one of those micro switches needing adjustment, and which one:

After the top has locked in the front, 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. Holding the wrench in the far locking position, push the soft top button forward and check whether the top now fully closes in the rear with the windows going up afterwards.

Try the same on the other side.

If you find that holding the wrench on one side does the trick, then that switch needs adjustment. I will explain the procedure below and include some pics that should illustrate what I'm talking about. Once you know how to do it, it's quite simple!

(You might get away with only adjusting the prongs on your soft top, following the instructions in http://www.benzworld.org/forums/r129-sl-class/1602807-soft-top-front-lock-adjustment.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.)

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 Front Locking Cylinder Removal.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".

Hope this helps, and please let us know what you find,

Klaus

Top Hydraulics | Rebuilt and Upgraded Convertible Top Cylinders, Pumps, Hydraulic Lines - Top Hydraulics, Inc

Why would you not just loosen the screw and move the switch?

 

Thanks

Klaus
Thanks for a really detailed response.
Will go and investigate your recomendation.
Will let you know the outcome
Regards
Steve:thumbsup:

 

roof problem

Klaus
Many thanks for your fantastic reply and very detailed info on how to check and fix the fault.
It was the front passenger side top bow micro switch as per your email.
I moved the roof position and alltered the top prong on that side.
The fault seems to have gone away , the windows now funtion correctly as well.If it comes back I will remove top section as detailed and bend lever.
Yes its the new roof that is very tight.
Fantastic:thumbsup::thumbsup:
Regards
Steve

 

temporary fix vs permanent

transcup,

I'm glad this worked for you. To summarize, the new, tight canvas and possibly new gaskets aka weatherstripping in the front have exposed the need to adjust the micro switch on one of the front locks eventually. The top wouldn't malfunction if the micro switch position was still within its allowed tolerance. You were able to temporarily fix the problem by making the new soft top not sit as tightly on the windshield header. That was achieved by moving one of the soft top prongs forward as per pic below. Moving the prong forward a little loosens the top above the windshield, and moving back tightens it up.

At some point, you may find that the chime goes off when you drive on bumpy roads. You can then do another temporary fix by moving the offending prong backwards a little to increase tension on the front again, but eventually you will have to bump the lever on the front lock micro switch as described before.

Klaus

Top Hydraulics | Rebuilt and Upgraded Convertible Top Cylinders, Pumps, Hydraulic Lines - Top Hydraulics, Inc

 

Hi can anyone please help _ have a R129 1992 model with a bow closing problem - on the closing sequence at the point where the soft top storage compartment closes the bow makes a very slight attempt as if to close but does not close. Once ever so often it might close or if one pulls the bow down to the closing position it will lock in place. I have tried bleeding the solenoid cylinder, and ensure the micro switch on the Left Bow extension cylinder is not bent but it still does not close. Also note the bow opens with out any problem but it is the closing action that does not work. Also about 2 year ago I had sent the Roof Controller to BBA reman to repair. This problem began occurring about 6 months ago. Can anyone please help. Much appreciated, Regards, Roger

 

Roger,

have you tried the following, described in post # 2 below?

After the top has locked in the front, 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. Holding the wrench in the far locking position, push the soft top button forward and check whether the top now fully closes in the rear with the windows going up afterwards.

Try the same on the other side.

Klaus

Top Hydraulics | Rebuilt and Upgraded Convertible Top Cylinders, Pumps, Hydraulic Lines - Top Hydraulics, Inc

 

Klaus the problem I have is the bow is not closing - or are you saying I am to adjust micro switch A25S2 to enable the bow to close. At the point in the sequence where the bow is to close and the softop compartment is already closed you see the cover make a pulled down action although it is already closed and the bow does not close ?? help please !!

 

Just a quick thank you to Klaus for this highly informative post, following his instructions I have just corrected the same flashing red soft top light issue on my vehicle. The adjustments required are very small as Klaus said. 20 minutes work to save a fortune, thank you so much.

 

Congrats on saving lots of money



Williamjohnhunt,

thanks for the feedback. Your response helps the search engines, and it gives others confidence to try this simple adjustment. As you said, the adjustment needed is usually tiny - on the order of a millimeter (1/32"), and it usually requires bending up the metal lever by about that little. If you bend it too far, then the switch will never register the open position. Thus, read first and try to understand how the mechanism works with its reverse logic.

Easy does it, in tiny steps, so that you can undo any errors you may have made.

This adjustment takes care of most cases where the chime goes off when you are driving, or when it beeps after you go over a bump, or when the rear bow (soft top section with the rear window) will not go down all the way. Holding the front locks closed with the soft top tool or the Allen wrench as described in post 2 below is key to figuring out whether a front lock micro switch lever adjustment will make any difference.

Klaus

Top Hydraulics | Rebuilt and Upgraded Convertible Top Cylinders, Pumps, Hydraulic Lines - Top Hydraulics, Inc

 

1992 500SL. Just paid to have front soft top hydraulics (?) replaced in prep for new soft top. Upon completion, indy reported soft top ceased opening (and closing) at point in process just prior to top going into rear compartment and compartment cover still open. Of course...
this never occurred prior to the repair. I have tried to associate the repairs listed here with my problem. I'm not able to.

 

lweljwel, your problem appears different from the original subject of this thread.

Please clarify which hydraulic parts have been replaced - you should know since you paid for it.

Also, please clarify whether the top is stopping at exactly the position shown in your photo only on the way up, or whether that is the exact stopping point when opening, as well. The latter would be unusual, and the first case is usually traced to a compromised micro switch on the left bow extension cylinder.

Lastly, has the top been replaced already?

It will be difficult to help you without an answer to these questions - please don't spare us any details.

Klaus

www.tophydraulicsinc.com

 

I have photos but don't seem able to attach from smart phone.

 

I've attached the photo of the "Stop point". Thanks in advance!

 

#1. The driver side and passenger side front hydraulic units top of windshield, replaced yesterday. By this morning, the small unit between those two atop the windshield had "sprung a leak" dripping through interior lights at top/windshield onto seats and console. I am relating facts at this point.

#2. It was shown to me that top from open position (inside trunk compartment) will begin to "close" but halt at the position show in the photo. I was told the same spot stops in the "opening" maneuver, but I didn't witness it. I am confident the top opened and closed fine prior to this repair, despite the leaking driver side hydraulic.

#3. The top was replaced over ten years ago at dealer in Pleasanton, Ca. No problems ever.

Thank you for your quick response. Is there any other info I can provide?
I have been instructed to return to the Indy tomorrow for the replacement of the 3rd hydraulic unit and "diagnostics" of electronics relating to the operation of the top. I have owned the car since new; 143900 miles; runs GREAT.
LWELJWEL@AOL.COM

 

I have been instructed to return to the Indy tomorrow for the replacement of the 3rd hydraulic unit and "diagnostics" of electronics relating to the operation of the top.

Which 3rd hydraulic unit? Did they tell you where it is located? Probably the distributor A 129 800 00 22 between the two front locks. Is the shop making you buy new parts?

If you are told that any of the ten cylinders in the rear needs to be replaced, please stop right there and have all cylinders rebuilt and upgraded at the same time. Do NOT buy new parts. Get rebuilt cylinders from our stock - they last much longer than brand new ones.

Klaus

Top Hydraulics | Rebuilt and Upgraded Convertible Top Cylinders, Pumps, Hydraulic Lines - Top Hydraulics, Inc

 

Klaus ..not sparing any details. ...I could go into garage right now..top is closed. ..
and attempt to "open" it and see what happens, ie, does it stop at the same spot in the opening cycle.

 

Thanks for your previous reply with a lot of detail, and I'm looking forward to learning where the top stops in the opening cycle.

Will try to respond in more detail tomorrow - it's been a long day.

Klaus

 

Great question...look

 

Klaus. Have a good evening..what's left of it. Looking forward to your response. I'll hold off on the Indy till then.
Thanks, Lynn

 

PS: If I wasn't clear, last photos are as far as it got in the opening process.

 

Good Morning, Amazing mentor Klaus!
I'm on pins and needles in apprehension!!
Despite my no - male status, I LOVE my car, am quite technical and detail oriented am quite technical and very detail oriented--and logical...could very likely do repairs. Maybe THE NEW TOP also IF YOU can SUGGEST GREAT MFGR, GOOD PRICE, QUALITY goods.:

 

Hello Lynn,

sorry about the late reply. Both positions have one thing in common, and that is the infamous micro switch on the left bow extension cylinder getting triggered. The cause could lie elsewhere, but this is what I would check out first.

When the top is opening, you are showing the tonneau cover open and the rear bow (rear window section) up. In that position, turn off the ignition and move the rear bow back and forth along the highest point. You should hear the micro switch clicking on the left bow extension cylinder around the 85-degree position. No click, and you have found the culprit. The left bow extension cylinder is a bit tricky to recognize. It is located a few inches above the top of the main lift cylinder, inside the moving soft top frame. See location diagram below.

Klaus

www.tophydraulicsinc.com

 

One more thought for something easy to check out: the "top down" switch next to the left tonneau cover lock. You can see its white plastic in your photo below.

This switch indicates whether the top is inside the storage compartment. Depending on the firmware in your soft top controller, this switch could be causing the trouble if it actually is giving the erroneous signal that the top is stored. Listen for the micro switch clicking inside the assembly as you push down the spring loaded part. Move the switch up and down a number of times, in case there is some dirt in it...

Klaus

www.tophydrulicsinc.com

 

Again, thanks. Regarding the "3rd" unit.
It sits under the windshield "cover", in the center. Silver, approx inch or so square.
Lays flat in center between driver and passenger. Reportedly leaking from small spot on drivers side of "unit". Was told replacement would be new. Looks pretty simple to me (they showed it to me).
I will check out the processes you suggested. Any more hydraulics WILL come from you!
You're great!
Lynn

 

Again, thanks. Regarding the "3rd" unit.
It sits under the windshield "cover", in the center. Silver, approx inch or so square.
Lays flat in center between driver and passenger. Reportedly leaking from small spot on drivers side of "unit". Was told replacement would be new. Looks pretty simple to me (they showed it to me).

Klaus:
P/N 129 800 00. Do you think that is the part that is now drenching me in fluid? It is mounted on top of the windshield, not on the bottom of the windshield cover.
Is that something I can buy from you and install myself?

That is the distributor p/n A 129 800 00 22. We currently advise to have that one upgraded at the same time as the front lock cylinders A 129 800 16 72 if you are in a hot climate and/or you have a model year up to mid-90s OR you don't want to ever have to worry about it again. See http://www.tophydraulicsinc.com/en/...2-rebuild-upgrade-service-for-front-hydraulic-distributor-above-windshield.html. You can order one from us in core exchange by selecting YES for "optional up-front shipping. There is a $100 core deposit, which gets refunded once we get the old part from you. The seals on our upgrades/rebuilds will outlast your car.

To remove the distributor, you will need to remove the dome light assembly. First remove the rear view mirror. The mirror is held in place only by a strong spring - pull down hard on the mirror, and it will pop out of the dome light assembly. To remove the dome light assembly, you must find the Phillips screws behind the map lights. The map lights swivel out: push on one side.

About the rest of your hydraulics: Once you see ANY leaks in the rear, please trust me and have all ten rear cylinders removed and shipped to us for rebuild.

Klaus

www.tophydraulicsinc.com

 

Klaus: Fuse? Just kidding I think. With ignition on and off repeatedly activated the "top down" indicator. No noise at all.
Then, I started from the beginning and checked the bow a t 85°. No clicking or noises either.
??????
I can't imagine that I have done these both wrong.
I will wait to hear from you.
Lynn

 

With ignition on and off repeatedly activated the "top down" indicator. No noise at all.
Then, I started from the beginning and checked the bow a t 85°. No clicking or noises either.

The symptoms on your top match the switch malfunctioning, and the switch not clicking would confirm that. Now you're down to confirming that the switch is really not clicking, finding out why, and fixing it. It is unusual that the micro switch on the left bow extension cylinder malfunctions if nobody has messed with it before, i.e., removed and replaced the left bow extension cylinder A 129 800 17 72.

Confirming: make sure to listen to a faint clicking noise a few inches above the top of the left main lift cylinder A 129 800 02 72. Again, that's when the soft top is up above the windshield, you have opened the tonneau cover, and the rear bow is up. Move the rear bow back and forth several inches from the highest position and listen for that click. No click: read through http://www.benzworld.org/forums/r12...rums/r129-sl-class/1547193-1996-bow-extension-micro-switch-fix.html#post4363007

Klaus

www.tophydraulicsinc.com

 

I did check the fuses I was aware of, to no avail. In trunk #3. Looked fine but did replace it.
#7..I guess it looks fine, wouldn't mess with that one.

 

Klaus:
P/N 129 800 00. Do you think that is the part that is now drenching me in fluid? It is mounted on top of the windshield, not on the bottom of the windshield cover.
Is that something I can buy from you and install myself? With whatever else I need that you sell. This is taking on a life of its own!

Lynn

 

Klaus, I have a rough time adding images.
I've run across a Y-shape tubing, 1/2 inch or so on right and left side. Appear to belong inside the blue plastic gromits (?) .
Both Y- s go into nothing. Could be exhaust??, but possibly should be connected to the small hole below both - right and left side. There is s lot of debris, pencils, etc, in those tight areas. I'm cleaning them while trouble shooting the bow device.

 

Klaus...now I am lost completely. I can find nothing wrong with the white switch. Can hear NO clicking while BOW is in top 85 ` position, HOWEVER....When sitting in car and activating the top opening cycle, the parts got to the same places, BUT, rather than abruptly stop as before, I heard a strange sound which continued..from the rear deck area..maybe pump, maybe very odd electrical? ??? AND...there is now a clicking noise on the white top down switch after aggressive cleaning, (WHEN i activate it BUT I think it's just mechanical noise of movement, not electrical.)
I am lost, I think.
Lynn
702-985-2295
Continued until I let go of red switch?????