Back windows work, front don't. I raised center console and put back windows on front switches and they still work. So I know the toggles for the front work. I didn't check power to the front wires that feed the toggles. I'll do this next. Fuses intact. Door skin off inside.

How do I get the motors out if it comes to that? I don't see how the wire feed comes off or how the motor comes out of its casing.

check wiring and the motor

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1986 300SDL, 211K,Dealership serviced its whole life
1991 190E 2.6(120k)
1983 300D(300k)
1977 300D(211k)

That doesn't answer my question.

Before you remove the motor try running a jumper from the battery to one of the terminals at the lower left in the picture and another jumper from ground to the other terminal then switch the jumpers to the opposit terminals. If the motor works then the wires at the door hinges are probably bad. If the motor still does not work the remove the three brass colored nuts that you can see in the picture and the window motor and frame will drop down. If you remove the motor hold up the assembly or it will just drop.
I just noticed that you can't see the third nut in the picture but it is above the V shapped piece.
Also look at this posting, I put in a picture of a window motor that I had disassembled.
http://www.peachparts.com/shopforum/showthread.php?t=246456

Attached Thumbnails

 

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1983 300SD
200000miles

I'm experiencing pretty much the same thing, except only one of my back windows works. That window is actually really slow to go up and down so I think I'll probably re-do that one too.
I do have a couple questions though: how quick are the windows on these things? (my working one is very slow, probably need to re-lube everything). Are there any replacement motors that are quick-moving/powerful and would fit? Is the wiring mentioned above a common problem, or are the motors usually bad? I'm not sure whether to tackle the CCU/AC or all the windows at this point, but summer is coming and I don't want to bake! Thanks!!!

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TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth

I had to replace one motor on my old 300sd @ $99. The mechanics were lubed at the time. It was the fastest window of the four, but was only steady, not really fast. I don't really know where to lube the workings. I'd go with the cheapest fix if I were you and that is probably windows, not AC.

If you look at the pictures in the link I posted that show the motor disassembled you can see the bushings that are at each end of the motor, those dry out and slow the motor down. Lube those bushings and clean up the brushes and you should be good.

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1983 300SD
200000miles

What do you lube them with?

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84 300D, 82 Volvo 244Gl Diesel

I used white lithium grease and it has worked for a few years now. When I started to take the motor apart I found the lower bushing was stuck on the armature shaft and was turning in the motor housing. It was hard to get the armature out because of the bushing being stuck like that but I eventually got it.
Thats what I love about these cars, you can fix things instead of replacing everything the way you have to do with newer cars.

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1983 300SD
200000miles

When I bought my 84SD neither of the two rear windows worked. I took out the switches and cleaned the internals and both have worked flawlessly for three years. A year ago my front passenger window stopped working. I cleaned the switch. Still nothing. So then checked for voltage at the motor next. It was getting voltage so it had to be the motor. Before I bought a new one I figured I would tear it apart. I did and relubed everything and put it back together and bench tested it. It worked. So I reinstalled it and it has worked ever since.

Next thing you need to do is check for voltage at the window motor while depressing the switch both directions.

IMO, most of the time it is not the actual motor itself dying. It is the switch, wiring, or stuck gears.

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2009 ML320 Bluetec
1985 300CD
1981 300TD

Past Mercedes
1979 300TD
1982 300TD
2000 E320 4Matic Wagon
1998 E430
1984 300SD
1980 300SD

The thing I have found is that the wires eventually give out where they bend back and forth at the door hinge. I have had to splice in new wires for a lot of functions. The wire they used must have been really good stuff it it could take that kind of abuse for 25 + years before it gave out.

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1983 300SD
200000miles

Okay, I unhooked the motor wires at the door and put the jumper cables to the motor. Sparks in both directions, but no motion. I put an ohmeter to the terminals and got .3 ohms. That seems about right. That leaves the window mechanism or the motor. Phil, I tried the three nuts you suggested, but that V mechanism barely moved when I tried to push the nuts out of the holes. If I force it will the window fall and do damage? Is there any way to get the motor out without dropping that V-piece down? I can't seem to get to the screws holding the motor into the gear box....no room to work.

I checked the switches by pulling off the front window wiring and putting on the back window wiring on the front switch. The back windows worked with the front switch, so the switches are okay.

Someone please correct me if I am wrong but I seem to remember that the motor and the window are attached to each other by the sliding jaw. You cannot just remove the bolts from the motor. If the motor is not working would not you need to move both the window and the sliding jaw so that the jaw slides out of the window rail - thus allowing you to remove the motor? (The only way I have removed the motor is when the sliding jaw has already broken.)

I am guessing that the weight of the window on the bolts is keeping the bolts from coming out and that the window will crash if he does get each of the bolts out??

So seems that the answer is to reach in and hold up the window, remove the bolts, then move the regulator and window up and down until the sliding jaw will slip out of the rail.

That seems about right. Have you read all posts on this thread? Any other suggestions as to where the problem might be? It feels like I have narrowed it down to the motor or regulator, but I'm not really confident of this.