If you haven't already done so, clean and lube your window regulators NOW to possibly AVOID having to even take them out, and possibly break!

I recently made a post about my driver's side window that was having trouble going up or down, on my 1991 300d W124.

Turns out it was the window regulator. I was VERY lucky that when it got stuck in the "all the way down" position, that I was just coming home from a meeting, and a very bad storm just finished up, plus I was only 1 mile from home. It would have been a real disaster had I been driving TO the meeting with the window down, it started pouring down rain, and wouldn't go up!

Though this is supposed to be a 'simple' repair, fixing this was a nightmare. It would have been easier had there been 2 people, but it was just me fixing this and trying to figure out how this all came out, then how it all went back together, over the course of a week.

You can probably AVOID having to even take yours out, if you simply clean off the old grease, and put on new grease. It will help the plastic glides slide along the rail like they're supposed to, and prevent them from breaking. Cleaning and re-lubing the gear teeth will help them glide easier and help prevent them from breaking, and it makes it easier on your regulator motor.

And I promise you.... doing that, is a LOT EASIER than taking out the entire regulator and figuring out how to put it back in if something breaks!!

What type of grease are you supposed to use?

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'81 300SD

You could use MB grease but it's very expensive. Sil-Glyde was recommended by a bunch of other people a few years ago when I had to do my windshield wiper as a good alternative.

You could also use a good lithium.

Every car I've ever had has done this. Window get stuck in the down position. Frustrating. My sedan is starting to have a problem with the rear driverside window but it just goes "kachugga chugga chugga" when I roll it up or down. Seems like the power is "flickering" on/off really fast. Going to look into that soon. I'll probably regrease everything while I'm in there.

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1985 300d smoke silver/red int. (204k) <--Sadie the 80's Mercedes from Hades!
1985 300TD 587 cabernet red/155 Creme (143k)
2007 Ford Expedition EL (54k)

"Seems to me you bought a hobby... not a car" - My dad.

For some reason MB went super cheap on the regulators... The pot metal is garbage. I didn't do much research and just bought regulators figuring mine were shot when I was heard the klunkchugchugklunk. Turns out the cheap metal the regulators are made out of will bend/warp over time. Once you get the regulator out you can check that it's straight and the teeth are matching up with the motor properly. There is a post on here somewhere with pics for straightening the regulator if that is what is causing the issue. Patience is huge when removing a regulator but after you get the first one out it's like ridin a bike.

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83 300D 144K never letting this one go!

Oh no. If your windows are doing that, don't use them again until you regrease. If they have a problem, you're going to be very, very unhappy having to fix these. Catch it before that happens, and you will save a bunch of time, and money. Simply scrape off old grease, reapply new.

My car is 22 years old with 180k on it. The regulators are fine. It's possible they got out of whack a bit on uninstall/reinstall, but they work fine. My automatic feature is messed up though. I hit the button to go all the way down, but they only go 1/2 way, then I have to hit the button again. Might be able to reset by disconnecting the battery when they're all the way down, and reconnecting; not sure.

My W116 windows make a 'thump thump' as they go up and down. IIRC, there used to be a repair kit for the regulators????

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Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership