Hi All,

This one's got me going. In my '87 260E, the driver's door power window slows down to a crawl at about 1/3 of the way down from the top. It also slows down in the same place on the way up. The passenger side is similar, but not as bad. I've searched the forums with words like "tight" or "stick*" along with power window and no one else seems to have discussed a similar problem.

I've got a couple of manuals & followed their procedures for adjusting the window. The nylon sliders "regulator guide jaws" they're called officially, seem to be in decent shape and I've cleaned & lubricated all the slide tracks, pivot points and the teeth on the big gear segment of the regulator.

The adjustment procedure seems to be pretty straightforward, and I've played with the adjustments in many combinations. The window zips right along for the bottom half of its travel and closes tight when it finally gets to the top. It just slows to a crawl about 1/3 from the top, occasionally tripping the circuit breaker from current draw.

The motors seem to work fine and the system voltage is 14.4 Volts when the engine's running so I don't think that's a problem.

Sitting back and looking at the mechanism, it seems like the back edge of the window is tight against the door seal. Moving the vertical slide forward about a mm might do it, but MB welded that part into the door. Probably with good reason so I'm not about to mess with it.

Any similar experience? Any solutions?

Tight,

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Norm in NJ
Next oil change at 230,000miles

Try spraying some silicone into the guides. Use one of those tubes attached to the spray nozzle.

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Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe

Norm

Funny you should post this email as I have a similar problem.

Mine is on the LH window on my CE. This is the passenger side on my car. The door on the coupe is frameless. I don't know if this is the same on the 4 door?

The drivers RH side works fine. Easy up and down.

The LH side is very tight through part of the movement as you describe and is accompanied by a squeaking sound.

I have done the following:

1. Removed door panel and fully inspected the working parts. All seem fine and I lubricated all parts and checked for interference. No obvious problem seems to exist.

2. By removing the lower external door trim the slider adjusters are exposed. I adjusted these to try and relieve pressure off the seals i.e by moving the bottom of the frame inwards the top of the glass is forced outwards.

Whilst I might of improved it marginally the problem still remains. I do believe it is intereference with the seals when the window comes in contact. On the coupe this is in the top half of the movement. There is quite a bit of 'shape' in both the glass and outer frame.

There is particularly a large contact point with the seal that is part of the rear glass.

I wonder if as the seals age there is additional rubber exposed causing excessive friction. The seals appear to have an almost felt like quality that would no doubt assist the sliding motion.

Perhaps the adjustment of the door is a large factor?

89 300CE
146k kms

Well, I tried spraying with a "dry teflon" lube in the seal channel. It maybe helped a little. This kind of confirms my suspiscion that theglass sits a bit too far to the rear. Unfortunately, that seems to be the one dimension that's welded in place. I think I'm going to accept this as "close enough".

BigBlue, On the 4 door sedan, there is a door frame that the glass slides in. I can play with the motor either door open or door closed & get the same results. All my disassembly in on the inside of the door, outside is solid. I know what you mean about the "felt like". It's kind of a fuzzy coated rubber.

Sounds like no one has cured these ills before.

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Norm in NJ
Next oil change at 230,000miles

I have the same problem in the front passenger door window in my 87 300e. Dissambled door, cleaned & lubed but no improvement. However, the glass seems to slide up with less restriction when the weather is colder, suggesting contraction of rubber seals is helpful. Hope someone comes up with something.

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87 300e (white/black; amg body kit)
88 300ce (red/cream; amg body kit)
93 300ce cabrio (white/blue/blue top)
93 300ce cabrio (black/grey/black top)
98 ml 320 (totaled @ 137,000 miles)
99 clk320 (black/grey/black top)

After a bit more investigation on the window I am of the believe that the external horizontal seal is the major culprit.

On the coupe the window can be operated with the door open and as it has no window frame this friction can be discounted.

I have noticed that the external seal is quite deep. It also has the longest and most consistent contact point to the surface of the glass. The coupe door is longer than the sedan door as well.

In trying to clean my seal I noticed that it is very dirty and heavily impregnated with filth and grime. I was able to remove a lot of this with a rag over a plastic knife carefully running along the seal.

I would suggest that replacement of these would make a major difference.

Does anyone know how it is done? Does the anodised trim piece have to come off?

89 300CE
146k kms

Last night I cleaned the tracks that the window slides on and sprayed silicone on them , this seemed to improve the window action. The tracks were lubed with white lithium grease before without any problems.Does anyone know the name of the nylon pieces that are attached to the window and slide on the tracks? Are they adjustable at all? After cycling the window up and down a few hundred times ( OK I'm exaggerating a bit)the only parts that seem to be slowing the window down are the slides on the tracks ? Of course the manual doesn't have a section on that so I'm in the dark , anyone else replaced those parts before?TIA

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Democracy dies in darkness, you have to kick at the darkness till it bleeds daylight

bump....

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Democracy dies in darkness, you have to kick at the darkness till it bleeds daylight

Pretty late on this thread. I believe your problem would be in the rubber seals. The felt like covering is wearing off. I have found that 3M makes a silicone paste that fixxes this problem for about a year.

I think I found the source of the "tightness" The guide-rails don't seem to be parallel where the glass mounted brackets slide.As the window went up past halfway the brackets were bottoming out on the rails and dragging. I pulled the brackets off one at a time and cleaned the sludge that was white grease off.I found remnants of a silicone grease inside the brackets so that's what I used when I put it back together (Sil-glyde).I adjusted the brackets in a hair and the problem seems solved

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Democracy dies in darkness, you have to kick at the darkness till it bleeds daylight