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Doug Vazquez 01-06-2001 08:25 PM

This post has no diesel engine content. I hope no one minds. I have the passenger side door panel off today, to see what is making the noise I hear when I raise the window.

Their are two gears approximately 3 inches in diameter that must mesh. The gear that is closer to the motor is not flush with the gear that is attached to the window arm. It stands proud, toward the inboard side of the door. As the window rises, the pressure seems to build up, causing the out of flush condition to get worse. Then, the gears start to skip teeth.

Is there any way to bend the cast bracket back into shape or add washers to realign the two gears? I imagine the regulator is toast, but I wanted to see if there was anything I could do short of buying a new regulator. The three other windows have problems also, however this one is the only one that was making the tooth skipping noise.

The motor seems to be fine, however, when the window is about half way up it would start to slow down. I suppose this could be a binding pressure slowing down the motor or it is just getting weak. I had the motor unbolted from the regulator and operated it. It sounded OK. Can one buy the regulator without the motor?

To remove the regulator, does the window need to be up or down to start with? Any replacement procedure advice would be appreciated.


patsy 01-06-2001 10:23 PM

I have a '79 300SD. When I first got it, my drivers side regulator snapped in half. Then, two days later the rear window broke too. Two regulators, in a week. over 300.00 dollars. You can bet that I took the other two door panels off and greased all of the sliding surfaces really well.

You can replace just the regulator, the motor is quite separate from that.

As far as bending the toothed jaws back into alignment, I don't think you will have much success. The reason being, that the regulators are pot metal, and are very unforgiving. They bend over 20 years and don't bend back. Eventually they get out of alignment like yours and snap from the stress.

Sorry for the bad news. Take care of the other three.

Replacing it is straight forward. I think if you have the window down to the point where you can see the bolts for the regulator through the openings in the door you will be fine. You can always hold the door panel up to the door and hook the wiring up to adjust the window level.

Grease Everything!!

mbdoc 01-07-2001 08:53 AM

You need a new regulator. Bending will break "pot" metal. One of the keys to replacement is to remove motor from regulator FIRST. There are 3 holes in door to remove these bolts. IF the new regulator does fit the WARPED door frame then use washers to allow proper fit.

Doug Vazquez 01-07-2001 11:33 AM


What did you mean by-"You can always hold the door panel up to the door and hook the wiring up to adjust the window level."?

The passenger side rear window seems to be in pretty good shape, maybe just lube required there. The drivers window is really slow. I don't know if only lube will help or not. The drivers side rear does not move at all, however I think I have heard some sound coming from there.

Thanks for the posts, all. The reason I tried this forum first is because there seems to be a higher concentration of older cars that are similar to old 300 SD. I sure do like this car. I would like to try to restore her sometime in the not too distant future.


MikeTangas 01-07-2001 12:10 PM


Patys means that you have to hold the door panel (inside skin) up to the door to hook up the window switch. Once that is done, you will be able to raise/lower the window after replacement of the regulator, to adjust the window level. You HAVE to hook up the door switch because the console switch will not operate if the line is open, ie: both switches have to be installed before the window will work.

Doug Vazquez 01-07-2001 02:40 PM


I guess I have not figured that the inside skin of the door comes off. I have the door panel off, and can see inside the door with a mirror. If I get on my knees and turn my head sideways, I can put my head in side the door, but it is hard to see much.

Are you saying that their is another skin under the interior panel that is removed before you remove the window regulator? If so, then removing the regulator has just gotten a lot easier to do.

Hope to hear from you soon. I will go look at the door again in a different light.


MikeTangas 01-07-2001 03:23 PM

The inside skin I referred to is the actual interior piece of door panel, with the window switch in it. Once that is removed there should be a weather panel, opaque plastic sheeting, which should be peeled off carefully. If you are careful you may be able to reuse it. Once that protective barrier is out of the way, you have access to the door innerds.

When testing the window, you will need to put the door panel up close and reattach the switch. Hope I clarified.

rickjordan 01-07-2001 04:00 PM

Doug, I too own a '80 300SD. I don't think you mentioned which passenger door, front or rear? Either way to lessen the confusion about the number of panels/skins I think I can help. Our door panels are actually 2 panels sandwiched together. First you have the part that makes up the door pocket and goes all the way to the top where you can rest your arm while driving. The other part is the panel has the waffle pattern to it. With the entire panel removed you can see how the 2 are held together by little metal clips. The other panel/weather barrier is like Mike said is just a plastic barrier. Your car may or may not still have these in place, mine are missing. The part that the door panel hooks on to is the door frame/shell. Then of course the outside would be the "skin" of the door. Now I don't know why you would have to hold up the door panel to the door to test the window. If it's the front door you are talking about then obviously the switch is on the console. If it's the rear door, the actual switch itself just pops out of the door panel. It's pressure held in place by 2 spring clips that are attached to the switch itself. With the switch removed from the panel, then all you have to do is plug it back into the connector in the door frame. Hope this helps.

Doug Vazquez 01-07-2001 10:39 PM

I was in the passenger seat today while my son was getting some wheel time ( he will be 16 in two weeks ), looking at the door ( the interior panel is still off ) and it did not look like there was another panel to remove to make accessing the regulator any easier. Oh well, I guess a guy can wish that a job will be easier than first thought.

I will plug in the service CD and wander through it for the procedure to remove the regulator.

Thanks again for the replies.


patsy 01-08-2001 12:03 AM

If you see the plastic sheeting covering the door, you are ready to go. If the plastic is gone, and you can see the regulator you are ready to go. Take a razor blade, and cut the plastic just past the glue that holds it on. Then when you are done, you can tape it closed to avoid drafts.

You will see everything if you look in all the openings with a flashlight. The motor, like M.B.Doc said, has three bolts in a triangular arrangement, I think. Undo those bolts to release the motor. Have the regulator up or down so that the bolts that hold the regulator on to the straight up and down sliding surface, are where you can undo them. As you will see, you only have a few portals to go through.

I hope you can find the directions on the CD, but I think you will be surprised by how easy it is once you are done.

Like Mike said, all I meant by holding the door panel up if you have to, is to roll the window to the proper level to access the bolts. Just to be able to briefly hook the wiring back up.

Doug Vazquez 01-11-2001 10:18 PM

Thanks for all the replies.

Rick, is that a photo of your SD? It sure looks in fine condition. If you don't mind me asking, what have you done with your seats? It looks as if you used sheepskin covers meant for high back seats. How do you like this arrangement? The drivers seat is in need of attention and I would like to come up with a reasonably inexpensive stopgap solution for the seat. The seat cushion is in need of rebuilding, also.

I think I see a passenger side mirror on your car and I have seen other SD's with them also. Our's doesn't have one. Is it very difficult to locate one of these mirrors? It does not look like it would be very difficult install.

Patsy, I have not had time to work on the car windows since last weekend. I was wondering what the part number is for these regulators so I can do some price research. Thank you for all the help.

patsy 01-12-2001 03:17 PM

I don't have the passenger rear view mirror either. I agree that the installation looks really easy. The price is pretty steep for a new one. Part no. 116-810-04-16(right side) will run from $250-360.00 roughly. A used one will cost around $150.00-175.00 unless you can find one from a junkyard or someone who is parting out a car. It would be well worth it to check all your local junkyards for one. Even if the glass is broken ,I would by one if the price was right. The glass can be bought for $40.00. It is part no. 116-810-14-21 (right side).

The right front passenger door lift is part no.
116-720-12-46. The price is around $120.00. The rears are around 90.00.

Doug Vazquez 01-12-2001 11:01 PM

Thanks Patsy,

I will put in for a budget request and start saving my pennys.


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