Um, ok... So the motor started working again. For some reason, it was stuck with window up. However, it's making the sounds I don't really like, and it sounds a bit irregular. Or maybe it's the drive system on the regulator structure that's sounding like that.

When the window is moved down and then up, it looks like the motor housing is torqued a little sideways during the direction change. I can't tell which gear is making the loud rattling sort of sound, but it's different sound for raising and lowering. I believe it's raising the window smoothly but sounds real loud when lowering the window.

What are some possibilities?

If you want to remove just the motor there are two torx screws holding it to the gear assembly. Remove the two screws and then you have to move the motor around by hand, sometimes even unscrewing the motor by turning the whole unit. I did this and found the bottom bearing frozen. Do not try to test the motor when its not attached to the gearbox as there is no upper bearing to hold the armature in place.

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1983 300SD
200000miles

It's likely the window regulator is deformed (twisted) such that the motor gear is not engaging the regulator gear correctly. That's probably why it was jammed. If you remove the entire regulator assembly and take a look, you will probably see the problem. I was able to straighten one, but some folks report that they will sometimes break if you put much force on them. If you take it out and mess with it, be prepared to replace it.

the regulator assembly is around $250 if i need to replace it, right?

There seems to be a few different versions for your car:

http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1CQ0J3JZ41TD138HQY&year=1984&make=MB&model=300-SD-002&category=All&part=Window+Regulator&appChassis=_any

A new one will be in the $200 range, but it might be worth checking the salvage yards for a used one. You shouldn't need the motor, just the regulator.

From looking at the assembly, it looks like the regulator is mounted to the door panel by 3 screws, and the guide rail is mounted by 2 screws. Also, the regulator is fixed to the bottom of the Aluminum window bracket by one screw... Am I missing any more points of attachment? Does the window need to be in the fully UP position to remove the regulator, or I guess that would be after I uncouple the regulator from the window by undoing that one screw....

That sounds right, assuming it is similar to my W123. You need to disconnect the regulator from both the window and the door frame, and disconnect the wires. I don't remember the exact sequence, but I think I had to lower the window partially to reach the connection between the regulator and the window. As I recall, it's fairly obvious once you get into it. Does anyone else have specific directions?

Deniss,

Having just done this on my 87 300SDL, here's the sequence I took. By the way, you really should consider buying the Service CD. Worth its weight in gold.

1) Run window down. For me, there was a bolt attaching the regulator to the window rail ( toward the front as you're looking at it). I adjusted height so that it was near the bottom but that bolt visible to put a socket on it.
2) Disconnect wires.
3) Remove bolts attaching the regulator to the door frame ( I believe there were 3 - one at the bottom of the door and 2 above the opening. The top ones were nuts attached to bolts in the regulator ).
4) Prop up the window with a block or make absolutely certain you have ahold of it, then remove the bolt holding the regulator to the window rail.
5) Slide the regulator forward, disengaging the slider from the window rail.
6) Remove regulator from door.

I found it MUCH easier to put the new regulator in the door, then bolt the motor on in place. The manual said to put the motor on, then install the regulator. It makes it so much easier to line up the bolts by leaving the motor off. Once I did it that way, it took about 10 minutes to install the regulator & motor. It will vary depending on which regulator you have, however.

- Ted

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1987 300SDL 265,000 mi.
1982 300SD 325,000 mi. (and holding)
1956 Packard Clipper 150,000 mi.

If I remember correctly on my old 126: I took the window out, took the regulator out, put the new regulator in, put the old window in, voila, pretty straightforward, however I did scratch the tints on my window somehow, oh well.

A santa barbara mb dealer was roughly 140 for that regulator.

Those instructions make sense. I have the Service Manual on CD, but I didn't have the access to the computer on which I have it installed. When I was looking in the cavity today, I figured the window had to be partially lowered so that the bolt attaching the regulator to window rail could be visible and accessible.

There also looks to be a guide rail for the regulator itself, mounted on the door panel towards the rear part of the door... It's mounted by 2 bolts. I assume I remove those too? They look pretty easy to remove.

On my 87, you do NOT remove that. There's a vertical plastic guide that needs to line up in that rail. My memory is failing me on the 82 - it was different, but that is a vertical guide and there is a plastic slider that fits in there to keep the window aligned as it goes up and down. I don't think you're supposed to remove that in the earlier cars either.

There is a plastic piece that fits into the window rail and needs to be lined up in that rail to make sure the window doesn't move around as it goes up and down.

__________________
1987 300SDL 265,000 mi.
1982 300SD 325,000 mi. (and holding)
1956 Packard Clipper 150,000 mi.

Lots of good info here. Once you have the motor/regulator ironed out, consider GENEROUS lube of the felt tracks with silicone spray. I get the $1.74 can at wally world. Old car windows fly up fast and it seems to last 1+ years.

__________________
1983 300SD 307k miles
1993 Ford Escort Wagon 215k miles
1995 Isuzu P'up 214k miles

There's an OE window regulator going for 225, and there's an aftermarket window regulator going for 120. Big price difference. Anyone think it might be a bad idea going with an aftermarket part on this?

The Aftermarket unit is made by PRIMAX... anyone heard of them?

Here's an update on my window problem. I pulled the motor/regulator assembly, and it looks like the teeth on one of the regulator gears are bad. They got rounded and sharpened over time and probably don't mesh too well with the motor gear teeth. The motor looks like it's been opened before because it's covered with sealant at the seams of the metal backing plate and sort of tied together with a few wire ties.

I ordered a regulator assembly from German Auto Parts (http://www.germanparts.com/), and they had a regulator for my car for about $120. It's an aftermarket unit, made my PIMAX Automotive Products, which is an Italian company. The products is stamped Made in Italy. It's made very sturdy, and the gear set-up is a bit more simple. The best part is - for $120, it came assembled WITH MOTOR! So I'll be returning the motor I got elsewhere - not bad for regulator AND motor for $120.

The fit is pretty good. Of course, there's always a little bit of difference from OE, but not much. All the assembly holes aligned, and I only needed to trim the part that attaches to window rail with a file a little, so that it's perfectly flush in the rail when the rail screw is tightened. Otherwise, window movement is similar to OE - smooth and quiet.

Hopefully it will last for a while!