I removed the drivers door panel to investigate a malfunctioning power window, here is what I found.

The 10mm nut in the middle of the door (about 10" straight up from the motor) had worked it's way through the hole in the metal, the round black plastic "thing" that the bolt is supposed to seat in, was sitting in the bottom of the door. The 10mm nut that secures the motor had almost worked through the metal.

I put some thick, oversize washers on, replaced the plastic "thing" and tightened the nuts. The window now goes up and down but I can feel a slight flexing of the metal in that area when I operate the window.

I know my fix was not a ccrrect one, please guide me in the right direction.

I notice the motor is moving, causing the inner door shell to flex.
When I lower the window, the motor is in it's correct position but as the window is raised, it torques/pivots the motor and flexes the metal. The single bolt that holds the motor is tight.

I've replaced several of the plastic guides in the windows of my 300SD over the years, and each time I R&R the regulators I'm amazed at the amount of inner door flex I see as I test the repair prior to buttoning up the door panel. Some flex seems to be normal (mine's going on 18 yrs.) but I'd check the channel alignment and "stop" to make sure that misalignment isn't over torqueing the mounting bolts. Of course it could have been just loose nut causing it to "rub" through.

__________________
The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)

Where is the window stop and how do I adjust it.

Thank you

It's on the upper rt. arm of the perforated "X" of the scissors of the actuator. An aluminum alloy piece held on to the arm with an anti-rotational bolt. To adjust, loosen bolt, it slides on a diagonal, sort of, and sets a lower "stop", to prevent too much downward movement of window. Check side channels to make sure the veloury stuff isn't too crudded up in the channel itself; perhaps a little white lithium grease on metal sliding/pivot points.

__________________
The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)

My '89 300SE's driver side window operates normally except
for the final closing, at which point it makes a forced clunk sound.
I thought that maybe the "stop" was faulty, but now I read that the stop controls only the final downward motion.
This sound only happens when the window is raised all the way
up to the point where the window can't go anymore. Now I
slowly raise it until it is snug up top and no air noise comes through.
This approach produces no clunk noise.
Sometimes, there is a clunk as the window comes down only if it was raised too far with the associated clunk noise.

Anybody have an idea of the cause or similar experience?

Thanks !!

__________________
1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
********************
1979 240D 140Kmiles (bought for parents) *SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD

I had similar problems on both the driver and passenger side windows. It is probably what the original post states. The mounting nuts of the regulator work their way into the metal leaving the regulator unsecured.
Take a look at it now as the regulator may bend or deform and is $$ then.

__________________
SANDEEEP
89 300SEL
230,000Km

THANKS!!!
Merci!!
Danke !!!

__________________
1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
********************
1979 240D 140Kmiles (bought for parents) *SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD

I had the driver's side regulator
changed. The teeth on the upper end were
gone and there was a crack in the body.
A larger washer was placed with the
bolt that holds it in place at center.

Moral of story: Don't raise your window
to the max. Just top it off enough
so that you have no wind noise.
This will deter flexing of the door's
sheetmetal 'skin'
and prevent regulator damage.

__________________
1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
********************
1979 240D 140Kmiles (bought for parents) *SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD