Power windows slow down, seem "tight" in the middle. - PeachParts Mercedes-Benz Forum

nglitz · #1 10-10-2004, 11:45 AM

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,

ctaylor738 · #2 10-10-2004, 07:14 PM

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

bigblue1 · #3 10-10-2004, 09:42 PM

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

nglitz · #4 10-10-2004, 10:06 PM

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.

richard28 · #5 10-11-2004, 11:37 AM

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.

bigblue1 · #6 10-20-2004, 08:55 PM

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

JamesStein · #7 10-21-2004, 10:58 PM

My '84 300CD has a similar problem. Aside from the fact that there are actually gaps in the seals.

I've had no luck at all finding a source for a replacement.

lino · #8 10-22-2004, 02:31 PM

Anyone have an update or good news for the rest of us with this problem?

sublettd · #9 10-22-2004, 07:09 PM

I've seen this topic discussed in other threads and the consensus seemed to be that the problem was not so much with the window as it is with the switch itself. People have opined that the switch is dirty and cleaning it will solve the problem. I know my rear windows are not raised and lowered as much as the front, and they move much slower than the front.

I just toss this theory into the discussion.

Regards,

rdanz · #10 10-22-2004, 07:28 PM

With the window in the down position spray the tracts with Silicone Spray .
Be generous it should clear up your problem.

lino · #11 10-22-2004, 09:54 PM

Will someone please suggest a quality brand of Silicone Spray the used as well as an electrical cleaner for the window switches.

Thank You

Kyle Blackmore · #12 11-20-2004, 05:52 PM

I'm experiencing the same problem with the driver's side front window on my 300CE . I've replaced the regulator (over 2 years ago) and at that time the window was working great. I sprayed white lithium grease on the slides a few monthes ago and all was good till a couple of weeks ago.I've removed the door panel again and everything seems OK , it just slows about halfway up and then seems to bind (on what I can't tell)and won't close completely. Fore /aft adjustment seems great , lateral adjustment seems to be correct , the manual says to loosen everything and start from there , I'm not sure if I want to do that as I remember what a finicky procedure it was. Any suggestions ? TIA

dmorrison · #13 11-20-2004, 06:11 PM

Quote:

Originally Posted by lino

Will someone please suggest a quality brand of Silicone Spray the used as well as an electrical cleaner for the window switches.

Thank You

Any silicone spray will work, I have Gunk silicone spray. WD40 was originally desiged to displace water on electrical circuits. Water Displacement #40. The 40th formula they tried. So use WD40.

Make sure you window regulators are not damaged. I had to replace both rear regulators in my daughters car. They were both warped and binding. Have never seen the regulator bend. Must have been caused by continuous use of the motor while the window was fully up or down. As I said I have never seen this in all the Mercedes I have owned

Dave

pmckechnie · #14 11-20-2004, 06:30 PM

I don't work on very many MB's, but I do work on a lot of Domestic and Asian power windows. The diagnostic procedure is to lub the tracts with silicon spray and the regulator slids and channels with something like white grease. If the problem is fixed, all is OK. If not the next thing is check the voltage going to the motor. Hook one meter lead to one of the wires at the motor plug in the door and the other lead to the other wire. Check the voltage going to the motor while raising or lowering. If you get a negitive voltage swap the leads. If you see at least 10V and it still runs slow then replace the motor. If voltage is low, check switches,etc.
I see a lot of motors that just get weak but switches either work or they don't.

Kyle Blackmore · #15 11-21-2004, 11:51 AM

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