W126 Sunroof binding on one corner? - PeachParts Mercedes-Benz Forum

Caseyjones955 · #1 11-03-2009, 09:26 PM

I searched but saw nothing quite like this. 87 300SDL

It has been working fine until today, I tried to open it but it would not go, so I tilted the rear up and that function worked ok, I tried closing it again hoping it would slide back so after tilting and closing a few times to try to get it to slide back it ceased to work at all. When it worked it was a little sluggish but did ok, I dont believe it to be gummed up as I just libricated it a couple weeks ago.

Thankfuly its in a closed position. I can hear the motor working and I can see the back of the sunroof rising and falling ever so slightly as I attempt to operate it. Looking on the outside of the car it would appear that the drivers side rear corner of of the sunroof panel is jammed slightly downward somehow. Any thoughts on how to correct this?

Thanks in advance.

Tony

Caseyjones955 · #2 11-05-2009, 12:20 AM

I got to messing with it some more today, The rear of the sunroof is jammed somewhere. One of the rear corners is higher than the other. I pushed and pulled on it a bit to try and free it to no avail. I can hear the drive system working, its not slipping, I can see it trying to open the sunroof but something is wrong, could it have come off the track?

Please.... anyone?

compress ignite · #3 11-05-2009, 02:59 AM

If so I may have BAD news... A broken "Angular Lift Arm" on that side.

W124 and W126 (with the rear Lift) are similar.

All Pictures and tutorials credit GSXR:

http://www.w124performance.com/images/W124_sunroof/

Caseyjones955 · #4 11-06-2009, 02:59 AM

Those look like expensive, difficult to replace hard-to-find peices. Maybe Im just exhausted but I cant find the tutorial, Im ready to go ahead and dig into this mess. If anyone could link a good resource, my search failed to find much for this and nothing on "angular arm".

It does have the pop up rear feature.

The other morning that pop up part worked a couple times, I worked it to try and free it up to go backwards (worked once before) but then it all stopped working. Now it just fights what appears to be a jam related to the rear of the sunroof panel. Usually searches answer my stupid questions before I have to ask them, this one seems to elude my search prowess.

Tony

Cal Learner · #5 11-06-2009, 09:58 AM

Quote:

Originally Posted by Caseyjones955

Those look like expensive, difficult to replace hard-to-find peices. Maybe Im just exhausted but I cant find the tutorial, Im ready to go ahead and dig into this mess. If anyone could link a good resource, my search failed to find much for this and nothing on "angular arm".

It does have the pop up rear feature.

The other morning that pop up part worked a couple times, I worked it to try and free it up to go backwards (worked once before) but then it all stopped working. Now it just fights what appears to be a jam related to the rear of the sunroof panel. Usually searches answer my stupid questions before I have to ask them, this one seems to elude my search prowess.

The tutorial is in another forum, not in the same place as the photos. Here's a re-print of the DIY write-up by DSXR (Dave M.):

How-to tips on W124 sunroof repair
Hi all,

In fall 2005, my sunroof made a sickening noise when I went to pop it open one day. I managed to get it closed, and left it alone until I had time to work on it, which was last week. One of the angular lifting arms, which are the fancy mechanical pieces that allow the sunroof to both slide open AND pop upward, had broken. And when I took things apart, the other one broke during disassembly! I had heard all the stories about how this is not a DIY job, and is best left to the dealer for $1000+ in parts & labor. But, being the tightwad that I am, I figured I'd try it myself first... and if I screwed it up, I'd have to let the dealer fix it.

The worst part is getting the sunroof disassembled with it broken. Normally, the first step in disassembly is to open the roof fully, then remove the liner and front rails. Well, that is not possible when the mechanism has broken. (See below for tips on how I did it in my case.) After getting the trim panel out of the way, I could see the nuts that were to be removed. I scribed marks around these so I could re-assemble in the same position later. With the metal roof removed, the hard part is over, then it's just a matter of carefully following the factory service manual procedure - which, I must say, is a little vague in some areas. I also marked exactly where the lift arms attach to the "transport bridge", the wide metal bar that the sunroof cable attaches to.

Once the lift arms, drip rail, and bridge are removed, you need to clean everything up and then re-assemble. The procedure said to lube moving parts of the lift arms with Gleitpaste (special sunroof lube), which I did. It also said to lube the rails, and the felt pads on the lift arms, which seemed weird but I did it anyway. (It looked to me like the felt pads would be fine with no lube, but oh well.) Installation was relatively straightforward. I had the pliers to pull the metal roof forward, but I really don't think they're necessary. The small plastic gauges are needed, and come in handy, but it took some head-scratching to figure out where they attach. I forgot to take a photo of them in place - wooops. When putting things back together, I used the marks I had made when taking things apart, and it turned out quite well - I didn't feel the need to do further alignment, it looks fine. And it works perfectly! I was a pretty happy camper by this point.

[IMG]http://***************/forum/images/smilies/smile.gif[/IMG]

If you are just taking the roof apart to clean it, the only nuts that need to be removed are the 2 on each side with the wide washers that attach the metal roof to the bracket on the lift arms. There's no adjustment here, no need to mark them, AFAICT. It's the two small screws on the side that attach the bracket to the lift arms that allow vertical adjustment for the rear of the roof - leave those alone unless you're replacing broken arms. The other important ones are the 6 screws that attach the arms to the transport bridge. Mark the position of the arms on the bridge - I just scribed a line along the edge. This is less critical, IMO. Don't mess with the nuts on the front of the metal roof panel.

The EPC indicates that the old lift arms have been superceded by new improved lift arms for early VIN numbers only - the break is the mid-1987 model year, and of course I had the early style. In my case, I needed both sides (at $100+ each), plus a new drip rail, new metal guide rails, and - allegedly - a new cable. However, you don't mess with the cable at all. The cable design was also changed, and the EPC says the old part "must no longer be installed". I'm guessing that MB figures if you're doing major sunroof work, this would be a good time to upgrade the cable too. However, it's not *required*. I already had the new cable, and figured I might as well go for it. It takes quite a bit of force to remove once it's run out of the motor, and kind of "jerks" out in sections - it seems to hang up periodically. Installing the new cable was awful - I almost thought I was not going to get it back in. With a friend helping to twist the cable, and me pushing, we finally got it back to the motor and it pulled the rest of the way in normally once it hit the motor drive gear.

Disassembly tips:
==============
This worked on my car, but I can't say it will always work - I don't know what the usual failure mode is:

1) You have to get the liner/trim panel off the sunroof. There are 4 plastic press-in clips near the front that must be popped downward. I was able to partially raise my sunroof, and pried it up by hand as best I could, propping it in position with whatever won't scratch the paint. Then, through the maybe 2-inch opening, I could shine a flashlight in to see above the liner panel. I used a long (24-30 inch), flat (3/4" wide by 1/16" thick) metal bar to wedge in between the metal roof, and the metal frame of the liner panel. This is VERY HARD to do unless you can look at another 124 with a good sunroof, and pop the liner down (with the sunroof opened) to see how the clips attach! Otherwise you can end up prying between the wrong pieces, like I did, almost damaging the very expensive trim panel. Once I figured out where to pry, I got the panel popped free, and could then slide it backwards and see the bolts on the underside.

2) With the liner out of the way, you can remove the two nuts with attached, wide washers. This allows the rear of the roof panel to pop pretty far upward. However, the front is still hooked under the rails. Remember, normal disassembly specifies to open the roof, *unscrew the rails*, then close the roof. With the rails out of the way, the roof simply lifts off with the 4 rear nuts gone. But not in my case. Since the roof is now separated from the lift mechanism, I lifted the rear up and manually pulled the roof back. It only moves a couple inches, but that's all you need to reveal the front guide rail screw. Remove the screw (both sides), push roof back forward. Lift the roof upward and prop it up with something that won't damage the paint. You can see the remaining 4 rail screws on each side. A small, flat, ratcheting screwdriver is what I used to fit in the very limited space to get the screws out. With those removed, the whole metal roof now lifts off the car, and the guide rails are also removed. The rest of the job follows the factory procedure.

Anyway, in summary, it wasn't nearly as bad as I thought it would be. And, I had no major alignment issues afterwards. Between using the plastic guide tools, and marking the bolts, it was quite painless. If your 124 roof is starting to act up, and you plan to keep the car long term, I'd almost consider proactively replacing the lift arms (and other parts) BEFORE they break. It will be a far easier job if you can still open & close the roof - trust me. The cost of parts are, roughly, $100 each for the arms, $70 for the new style drip rail, and $15/pair for the new style rails. The new cable isn't needed, but will be $60 or so if you want to do that too. Prices are based on current wholesale, Dec-2005, and of course are subject to change, etc. If your car is after VIN #A354333 (for sedans), you probably don't need all those parts, just the lift arms, which appear to be the fragile/stressed item.

I'd almost say it's not that bad of a job to fully disassemble a working sunroof, for a proper cleaning (note all the greasy crud on the old arms in my photos), lube, and re-assemble. Just don't force anything - it should all come apart without major effort (except the sunroof cable replacement, which I would avoid if possible.)

Photos are here:
http://www.w124performance.com/images/W124_sunroof/

If I ever do this again, there are a couple things I'd like to add photos of, like what the plastic install guides look like when inserted, etc.

=)

Best regards,
__________________
Dave M.
Boise, ID
1995 E420 - 161kmi (W.I.P.)
1994 E500 - 104kmi (Q-ship)
1993 300D - 185kmi (For Sale)
1987 300D - 303kmi (Sportline Stage 2)
1987 300D - 247kmi (R.I.P)
Click here for my website photos, documents, and movies.

compu_85 · #6 11-06-2009, 10:25 AM

The parts are still available at the dealer, and cost about $50 per side.

EDIT: that is for the later style that does the pop up and slide back. FWIW mine failed because the seal wasn't fully seated, putting extra force on the mechanism as it tried to push its way through.

-J

Caseyjones955 · #7 11-06-2009, 11:09 PM

Great, thank you. That writeup should be enough to get me in there so I can visualize what ever it is thats broken.

Thanks for the article and pics. I love this forum.

Caseyjones955 · #8 11-07-2009, 05:13 PM

It was a lift arm, getting the thing apart was a chore becuase it would not open until I pulled the sunroof liner down and removed the nuts that hold the panel on. The pass side lift arm assembly came out in peices.

Is there ANY alternative fix? Even if I were anywhere near the correct parts I would have some difficulty paying for them until the end of next month. I need to use the car Monday, the weather is likely to turn ugly before tomorow night and I cant see any way to get it back together.

Any suggestions? Has anyone ever found a way to do this manually? Im getting really sick of dumping money I dont have into this effen car. I can't even find the parts on Ebay. This car is so far from the trouble free reliable operation of my former 300D

Thanks.

Cal Learner · #9 11-08-2009, 10:17 AM

Casey, I've never done that job before, so I'm not speaking from experience, but I'd be surprised if there was a work-around, inasmuch as the lifting arm not only performs that function, but is part of holding the sunroof assembly in the proper geometry so that it closes and seals at all. The right side lifting arm is available on the Internet for about $95. If you add the little felt bits and such, you can probably get by for under $150, if you do the work yourself.

Caseyjones955 · #10 11-08-2009, 11:57 AM

I cant see any simple workaround either, simpler to just replace whats broken (and will break soon enough) its aligned fairly well so I think it will get me through until I get a first paycheck (finally got the job I've been pining for). I hope its weather tight in it's temp position.

Im really frustrated with this car, it's been a money hole since I brought it home. I havnt had to do this much to make/keep a car roadworthy since I kissed GM goodbye. Im burried badly in this one, I'll do the sunroof correctly as I have to keep this car to get my moneys worth from it in use. I have 2 kids coming up to driving age. darn. -/ rant mode off

Any links or source to the most cost effective lift arm assemblies are certianly welcome. I plan to source the other felt pads and seals from Phil if he has them. I would really love to get out of this for < $300 if possible.

Thanks.

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