W220 sunroof stuck - PeachParts Mercedes-Benz Forum

bhatt · #1 08-29-2011, 02:52 PM

I have a W220 S430 and the sunroof is stuck. Here's the background:

-Worked properly 1 year ago. But last fall it started to get slow
-I lubed it (obviously not properly or enough) and it didn't get better
-By the end of last fall, it was jamming up and needed extra hand pressure to assist the motor in sliding it open or shut
-Now it won't open at all. Motor runs for a second then clicks off (probably because it is sensing that the glass isn't moving)

So now I have a roof that hasn't moved in 1 year but I want to get it unstuck. Can't open it at all to lube it.

a)is there any way to access the rails to spray some lube in there just to get it open once?
b)if not, how do I get to the mechanism easily to try to get some lube in there? I don't want to remove the headliner, but can I get the sunshade out or something? (the sliding panel) That might let me get to the mechanism.

I'm sure if I can spray the heck out of it just once, it will move. Nothing is mechanically or electrically wrong with it, but it's probably clogged up with dried up lube so it won't move any more.

Help!

RichardM98 · #2 08-29-2011, 06:26 PM

Haven't had to take mine apart yet but...

1) There are DIYs on disassembly and lubication. I think there's even a Youtube video.

2) You can use the hand crank to open it. Drive is under the left overhead light lens. Just pop lens and you'll see hole for 5mm hex. Your car should have come with the crank. You are working against the motor's gear train so slow and steady does it.

3) MB makes a special lubricant for their sun roofs. It could be that whatever lubricant you used interacted with the MB stuff and congealed. Just a guess.

Hope that helps some.

bhatt · #3 08-30-2011, 10:08 PM

OK did some more diagnosis and here's what I have found.

When I push to the open, close, or lower positions, the motor goes "click-click". It tries to move (first click) then shuts off immediately (second click). It is obviously protecting the motor because the roof won't move.

When I push to the upper position (raise the back of the roof) it doesn't do a thing. No noise at all.

But here's the weird part. I put a 4mm hex socket into the hole in the motor (under the left light cover) and as hard as I crank it with a huge socket wrench, it won't turn in either direction. Tried to hit the switch and lean hard on the wrench in the same direction, but I can't turn it.

I pulled down the accordian shaped rubber on each side (interior of the car) of the sunroof. Sprayed the mechanism with about a 10 second spray of WD40 on each side. Roof still didn't move.

So now I'm not sure if it is the mechanism, or maybe the motor.. that's my new suspicion now!

Is it possible that maybe the motor was getting slower all along (not a problem with the tracks)? And now it is jammed up/siezed?

The weird thing is last summer when it started to get slow I in fact DID lube the roof but it didn't make a difference. I lubed every sliding chrome rail I could find but it didn't make a difference at all. I used the MB lube that I purchased a few years ago (had some left) so I used the right stuff. Didn't speed up the roof a bit.. it was as if I didn't lube the roof at all!

So I'm starting to think that the best idea is to pull the motor and see if it turns. If it is jammed, I'll replace the motor. If it turns without the sunroof attached, I'll keep looking into the mechanism.

Any further thoughts before I start tearing this apart?

bhatt · #4 08-30-2011, 10:54 PM

Removed motor and it works perfectly. So the mechanism/cable is definitely jammed

I can see a little bit of the cable through the hole where the motor drive fits in. It's got a little bit of rust around it, and so does the frame that the cable goes through.

I think there is rust and crap in the tubes or holes where the cable goes through. There is definitely rust in that area of the car because I had the roof painted and it was all bubbling up at the front edge. That was about a year ago, so I'm sure there is still a bunch of rust on the inside of the roof where the cable sits.

So I think I can pull the cables out, clean them, lube them, and reinstall. That should fix the problem.

But how do I get the cables out? Mercedes WIS says to open the roof (or maybe tilt the roof.. don't remember) and remove the glass panel, then unscrew the ends of the cables.

But my roof is frozen shut so I can't do that. Any ideas?

I tried to operate the roof manually by moving the glass in any direction (once the motor was removed) but can't do it. So cables are definitely siezed up.

How do I get the cables out?

(option 2: I'm gonna get a can of spray white lithium grease and start shooting it anywhere I can see the cable. Hopefully I can get it unstuck just once to be able to open the roof.

HarryM · #5 08-31-2011, 11:03 AM

Response to you #3 post.

When you insert the 4mm crank into the socket, you have to press it in (which releases the gear) before attempting to turn it. Left = Open, Right = Close.

This procedure is in the owner's manual.

bhatt · #6 08-31-2011, 11:23 AM

Aha! I didn't think of actually reading the manual

I have reinstalled the motor and will try tonight to push in and turn the 4mm hex to see if I can get the cables unstuck. I sprayed the hole last night (where you can see the cable) with a bit of WD40 so hopefully 24 hours of soaking in that + turning the motor shaft with a socket will unstick the darn thing.

Thanks!

Ferdman · #7 09-01-2011, 12:05 AM

bhatt, if the WD-40 doesn't loosen things try PB Blaster.

Alialzaher · #8 12-08-2015, 05:41 PM

Good day gentleman,

I have the same problems sunroof just click click can I have any help