sunroof won't open - PeachParts Mercedes-Benz Forum

rgnprof · #1 03-25-2006, 03:00 PM

I can't get my sunroof open (1978 300D) - motor runs in both directions but just grinds when I try to open it. I tried using the sunroof tool in the trunk but while trying to turn it open manually, it was very hard to turn and this tool broke off. Any ideas?

Ryan

Austin85 · #2 03-25-2006, 09:21 PM

BEFORE you do anything to the cable;
Good chance your problem is a worn out gear.
Don't mess with the cable or remove the headliner yet.
YOu need to inspect the big orange fiber gear inside the motor.
If it's worn you can get a new one on line or find one at a U Pull It if lucky...

Remove the motor by loosening the 2 mounting bolts;
OPen the motor up by taking out the 3 bolts on the inside of the motor.
unscrew the nut under the plastic cap, and remove it;
You should be able to slide the gear out of the motor and slip the orange fiber gear off the spindle.
If it's worn on the inside of the gear you need a new one; if it's worn on the outside of the gear you need a new one.
You are better off checking the gear (it's been wearing out for 28 yrs.) before you start to mess with the cable.

If your gear is good. And you need any other help let me know....

rgnprof · #3 03-25-2006, 10:18 PM

Thanks for the replies - How do I get to the motor? From inside the trunk? Any trick here?

Ryan

Austin85 · #4 03-25-2006, 10:47 PM

Quote:

Originally Posted by rgnprof

Thanks for the replies - How do I get to the motor? From inside the trunk? Any trick here?

Ryan

IN trunk ;
Didn't you already manually turn the motor????
On left side remove the plastic wheel well liner
upper l side is the motor behind some metal hinges...
get a wratchet socket set to fit bolts
2 bolts hold the motor to the frame
unplug the motor clip...
unclip the back metal guide tube
unclip the frony guide tube
don't lose the little black clips!
you should be able to slide the motor off the cable
IF NOT have someone push the SR button to open / or close? while you have the motor in hand , and slide it off the cable

Now you can open the motor by removing the 3 smaller bolts on the housing to access the gear.

rgnprof · #5 03-26-2006, 01:07 AM

I tried - w/o much luck and I did not have to remove anything to get access, using the sunroof opening bolt. I thought that I had read in an earlier post that I needed to get the roof open manually before I could get access to the motor - must have misead. I really haven't tried much yet - didn't want to get it stuck open.

I am going to try and follow your suggestions tomorrow.

Thanks, ryan

bgkast · #6 03-26-2006, 01:43 AM

My sunroof in my 240D has a similar problem. It will open, but not close fully. It makes a clicking sound like a gear slipping when it gets stuck. Using the manual tools causes the same noise. I removed the motor from the gear box and removed the plate that covers the gear box, but all of the metal gears in the gearbox look fine. Is there a plastic gear elsewhere in the system? How do you remove the gear box from the cable? Can the teeth on the cable strip out easily? Thank you.

Austin85 · #7 03-26-2006, 12:09 PM

Quote:

Originally Posted by bgkast

My sunroof in my 240D has a similar problem. It will open, but not close fully. It makes a clicking sound like a gear slipping when it gets stuck. Using the manual tools causes the same noise. I removed the motor from the gear box and removed the plate that covers the gear box, but all of the metal gears in the gearbox look fine. Is there a plastic gear elsewhere in the system? How do you remove the gear box from the cable? Can the teeth on the cable strip out easily? Thank you.

Metalgears won't wear out. There is a big orange 1 7/8" fiber gear held on by the adjustment bolt in the center ...

http://www.autoluxmbz.com/index.html

to remove gear box you can flip it over while still in trunk and unscrew plate; then the adjusting bolt then slip out the fiber gear...(Don't drop parts in trunk...)
The cable can wear out , but not likely. You can visually inspect it .

#8 03-26-2006, 01:00 PM

Try adjusting the clutch on the motor, it's the little nut on the motor. Just tighten it a little at a time, and then test to see how well it works. When it opens and closes at a good speed, then call it good, you don't want to over tighten it.

deerefanatic · #9 03-27-2006, 03:55 PM

NOT a good idea.

Over tightening that clutch can damage your motor or gear train. First, he needs to get that motor off and make sure no damage is present. If so, fix that first. then he needs to reinstall and check clutch torque in the following way:

Install motor and put a torque wrench with proper socket on the plastic drive nut. If it is a dial torque wrench, great. If it's a "clicker" torque wrench set to between 7-10 Newton-Meters. Then, install on the drive nut like you're going to "turn" it. Have a helper operate the sunroof switch and read torque on wrench or listen for click. dial wrenches work better for this. Torque should be between 7-10 Nm. If it is, then don't tighten any more. This is plenty to move a well greased roof with no other probs. If roof still doesn't move smoothly (like mine didn't) then you need to get some sunroof grease and get in there and clean and grease the sunroof slide system.

If you do this and you don't have worn jaws or bent rails, your roof WILL work as good as new.

rgnprof · #10 03-27-2006, 05:53 PM

OK, I've got the motor and the gears out - I had to take the 4 bolts off the gearbox and remove the counternut and the gears themselves to get it off because the cable will NOT budge. The gears, including the plastic/fiber one, look fine to me but I am now stuck! I still can not get the roof open and it seems that before I can do anything else - remove teleflex cable, grease it, etc. I have to have the roof open! I have about 2-3 inches of cable exposed out the tube in the trunk but I could not get the cable to budge! I guess the roof could just be stuck but I am at loss as to what to do next.

Ryan

bgkast · #11 03-27-2006, 06:11 PM

I still can't get my gearbox off the cable.

I have removed the 4 bolts and back plate, but can't seem to get the gears off of the cable. Austin was right the gears are not metal, but my gears are not orange. The teeth that are visible look fine, but I cannot see the teeth that contact the cable. What sort of sound (if any) does the clutch make when slipping?

rgnprof · #12 03-27-2006, 08:49 PM

I got the gear box off the cable by loosening the large counternut - it's a 15 mm nut with a hole in it (the manual sunroof tool actually goes inside this hole into a slot inside). I read deerefanatic's post and I don't know where the "plastic drive nut" is that you use your torque wrench on??? I don't see any plastic nuts...

I don't know what the clutch sounds like either??

I did try to reconnect the cable to gear box (transmission, I guess) and when I hooked the motor and had my wife hit the sunroof switch, the motor just spun, didn't engage the gears at all, so I'm still confused.

I lack basisc motor understanding, but I'm learning...

Ryan

BTW, all of my gears are metal except one (and it's a white plastic/nylon gear. All look fine.

rgnprof · #13 03-29-2006, 08:56 AM

Can anyone help here? I tired to tighten the clutch and the motor is not engaging the cable at all now - it just spins and I hear no grinding noise. Again, the gears did not look stripped and from what I could see the cable looked fine as well.

Ryan

Jimmy Joe · #14 06-01-2008, 11:08 PM

old thread; good info.

I am wondering if anyone has a pic or a part number of that gear that can wear out in the motor, so I have a starting point to go on. Thanks.

dave_zook@hyper · #15 12-15-2008, 09:39 AM

I have a sunroof problem also but I don't think it is the motor. The motor worked well in my 85 300sd until one day it didn't. When I hit the switch on the dash, nothing happens. My instinct says that it is the switch itself. Am I right?

If so, are there any tricks to replacing it?

Thanks.