Power Window Problem- 1986 300e

[banana_man88]

Hello!

I've searched through previous posts on this board but am still a little confused as to what part(s) I may need to solve my problem. I have a 1986 300e and the driver side window comes down quite slowly and goes up even slower (often I aid the window up by pressing my palm against it and sort of helping it go up). I suppose this means that the switch is working and I believe the other windows work. Does this mean that I need to replace the power window motor (part O3050-70350 on Fastlane) ? I am not sure what the window regulator that I see numerous discussions about does... Sorry if this is a complete noob question but any help would be greatly appreciated!

Thanks,

Allister

Originally Posted by banana_man88

Hello!

I've searched through previous posts on this board but am still a little confused as to what part(s) I may need to solve my problem. I have a 1986 300e and the driver side window comes down quite slowly and goes up even slower (often I aid the window up by pressing my palm against it and sort of helping it go up). I suppose this means that the switch is working and I believe the other windows work. Does this mean that I need to replace the power window motor (part O3050-70350 on Fastlane) ? I am not sure what the window regulator that I see numerous discussions about does... Sorry if this is a complete noob question but any help would be greatly appreciated!

Thanks,

Allister

The window regulator is the mechanism that pushes the window up and down:

http://catalog.eautopartscatalog.com/mercedesshop/sophio/quote.jsp?clientid=catalog.mercedesshop&cookieid=1CQ0J3JZ41M21CBH2Z&baseurl=http://catalog.peachparts.com/&partner=mercedesshop&year=1986&product=O3040-16404&application=000286562

The motor bolts to the regulator and drives it. The small gear on the motor meshes with the big gear you can see in the photo. You need to remover the regulator and motor as a unit, then you can remove the motor from the regulator.

[banana_man88]

Thanks for the quick response!

So does this mean that I will need both the motor and the regulator to fix my problem? Or is a very slow moving window indicative of motor failure (do these motors get weaker and weaker or just die?)? Or is there something wrong with my regulator?

Thanks again!

Originally Posted by banana_man88

So does this mean that I will need both the motor and the regulator to fix my problem? Or is a very slow moving window indicative of motor failure (do these motors get weaker and weaker or just die?)? Or is there something wrong with my regulator?

I doubt you need both, but the only way to find out is to take it apart and look. If you can watch it operate you may be able to see if the regulator is binding and slowing the window. I think it will be obvious if there is something wrong with the regulator. My best guess would be the motor, but there are probably others here who have more experience troubleshooting these things.

[simmo300e]

you may get some relief by applying grease to the runners and guides in the regulator mechanism but my experience suggests your motor is failing, particularly if you are hearing any noise during operation.

for the front windows, you can change the motor only but the on two back windows the motor and regulator are integral, which makes the mechanism a bit more expensive.

i have had to change all four motors in the last 18 months on my 87 car, which gives you some idea of the life span of these components.

they fail in a number of ways, most often totally, but the back mechanisms sometimes jam halfway down. Increased noise during operation is an indication that the motor is failing internally, at least in my case.

if you plan on doing the job yourself, you'll need to do a search on removing the door panels. i posted a sheet from the WIS on how to do this some time ago. changing the motor is a bit of a pain the first time but you'll get the hang of it. helps to have an extra pair of hands to keep the window glass up and out of the way while you're trying to remove the motor and regulator mechanism.

good luck

[banana_man88]

Thanks a lot for the help Craig and simmo300e. I will open up the doors and take a look and post my findings/solution after it's all done!

[hanno]

A bit of silicone spray in the fuzzy glass guides will defer the time and cost of replacement for a while (at least it has in my statistical sample of one) :-)

[dlssmith]

Don't forget to order the new nylon slide when you replace the regulator. It's pretty easy to change, the slide and the regulator, especially if the window is still operating. The regulator is really the weak link, though. The motors are quite strong, and I doubt they wear out all that often.