Sunroof failed - PeachParts Mercedes-Benz Forum

elau · #1 07-01-2002, 12:20 PM

OK, I have researhed the forum and most of the threads discussed the possible cause of the sunroof failure. I am sure my problem is caused by all of the causes mentioned. But how do I get the headliner removed to get to the mechanism? I don't want to fix it so it can be opened and closed. I just want it closed. My sunroof failed yesterday, it open half way and stopped. It will not go back to close position, and I can hear and see the motor runs (in the trunk). I tried to manually close the roof but it won't move an inch. The car is a '87 300E with 300K on the clock. I have other things to fix before I spent $$$ on the roof, so I just want it closed before it rains. Please help.

BTW, I pulled the roof from inside the car and it is now two inches from completely closed. But water will still come in if it rains.

JimSmith · #2 07-01-2002, 01:28 PM

elau,

You have to open the sunroof about half way or more, then unsnap the 4 clips on the forward edge of the sliding roof panel that hold the liner to the panel. Once they are clear, you pull the headliner forward and up out the roof openning.

There is some kind of guide tube sleeve on the inside of the headliner that you have to engage when putting the unit back together. This is new to me, and I am looking at the CD manual instructions. I have personally only worked on the simple sliding roof without the pop-up feature, and it has no such provision.

Once you get in there you should be able to figure out the mechanism and close the roof by hand. You will not be able to get the liner back on under those conditions though as the headliner is wider than the opening in the interior and springing it into place will likely make it deformed for life.

Good luck, Jim

JimSmith · #3 07-01-2002, 01:43 PM

elau,

Since you did not mention you hear grinding noises and the like, I figured your motor is running but the cable is not moving. There is a clutch in the drive system intended to allow the motor to turn after the sunroof panel reaches its end of travel in the open and close direction. If your system is not internally broken, you may just need to adjust the clutch.

I read some additional stuff in the manual and it may help for you to measure the torque output of the clutch/motor system by putting a torque wrench on the emergency manual activation nut in the trunk (plastic 16 mm nut) and have someone else try the motor. You should see a nominal torque value of 6 to 7 Nm, which is not a lot. You can adjust the clutch to transmit greater torque, but the manual cautions you not to over tighten it so it locks up. A good cleaning and lubrication of the mechanism should also help reduce the torque needed to move the roof panel. After years of operation it is feasible the clutch is wearing a little too, so an adjustment and cleaning may be in order.

The procedure for adjusting the clutch is to take the plastic nut off(it apparently pulls off) and use a wrench to turn the nut that is now uncovered (hold the shaft with an open end wrench of 6mm "in the place provided") clockwise to tighten the clutch. Turn it no more than 60 degrees and then check the the torque again, making sure the clutch releases. Adjust it to restore or even add a little torque to the cable drive and see what results.

Good luck, Jim