[MBZ] DIY W124 sunroof repair

Thu Feb 2 04:58:22 UTC 2006

thats a keeper.

Dave M. wrote:

> Hi all,
> 
> Last fall, 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 section 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. :)
> 
> 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-assembly. Just don't force
> anything - it all comes 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
> 1994 E500 - 95kmi  (Q-ship)
> 1987 300D - 261kmi (Sportline)
> 
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> 
> 

-- 
Kaleb C. Striplin/Claremore, OK
  89 560SEL, 87 300SDL, 85 380SE, 85 300D,
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