Removing Rear Window Motor on 124 - PeachParts Mercedes-Benz Forum

justinperkins · #1 07-22-2007, 02:56 PM

My left rear window motor doesn't work, I'm hoping it's just stuck or needs to be cleaned, so I want to remove it. It's stuck in the up position and of course the FSM says that to remove the motor the window needs to be in the down position.

The cable that lowers the window seems to be under pressure (the one the pulls the window up), so I'm really nervous about unbolting it with all that pressure on the system.

Anybody have any experience removing the motor and have any tips to share?

lietuviai · #2 07-22-2007, 03:03 PM

Try disconnecting the electrical wire and run a jumper wire to see if you can get it work that way. The motor and regulator come out as an assembly so there is no worry about pressure.

justinperkins · #3 07-22-2007, 03:06 PM

Quote:

Originally Posted by lietuviai

Try disconnecting the electrical wire and run a jumper wire to see if you can get it work that way. The motor and regulator come out as an assembly so there is no worry about pressure.

I know the motor is getting power, that's not the issue.

Jeremy5848 · #4 07-22-2007, 03:25 PM

Quote:

Originally Posted by justinperkins

My left rear window motor doesn't work.....

I had the exact same problem in May of this year with the exact same window on the sedan version of the exact same car, so.....

I ended up cutting the cable (a non-reversible option!) with wire cutters in order to lower the window, disconnect the linkage, and remove the regulator and motor. A fairly easy R&R job except for getting all of the clips on the inner door skin back in place -- took both of us.

Never did figure out what was wrong, the motor was good, maybe a jammed or broken gear. I bought a used replacement from somewhere on line....[looking]...aha, an eBay seller, $20 plus shipping. (YMMV.)

If it happened again, I'd probably fix it the same way.

Jeremy

Garrett90250 · #5 07-22-2007, 03:28 PM

I'm a newbie, but I actually just did this 2 days ago on my 87 300SDL. Window was stuck up. I could tell it had power because after removing the door panel, operating the switch would yield a very slight wiggle of the motor.

To get it out:
Reach way up inside of the door panel and unhook the black clip that holds the white slider captive to the metal window rail.

On the accessible side of the door skin, there are 3 10mm nuts that hold the motor portion (in a triangle) then there's a 10mm screw at the top and bottom of the track. Undo all of these and push the whole assembly slightly inward to free the studs on the motor portion. Rotate this assembly toward the door latch and gently lower the window. This may require another set of hands. Slide the white plastic do-hickey free of the window and pull the window back up.

With a little bit of wrestling, the entire motor assembly will come out.

The issue with mine was hard crusty grease. Two screws and the motor pops out. 7 or so screws and the whole assembly will pop apart. Take the whole thing apart, but be very careful, it's easy to crack the housing. Clean out all of the old grease and see if you can't get it working again.

There's a cable spool in there that's a bit of a bear to get back together, just take your time taking it apart and it shouldn't be too much of a problem.

Good LUCK!
-Garrett

justinperkins · #6 07-22-2007, 03:58 PM

Thanks a bunch Jeremy and Garrett, excellent advice and exactly what I was hoping to hear!

I'm in the middle of removing my window tint, decided to tackle that project while I was waiting for responses. Hopefully I'll get to the window motor today, but we'll see how long the window tint removal takes. Just finished the rear window, man that was a bear

Thanks again, I'll update this thread once I figure it all out.

Jeremy5848 · #7 07-22-2007, 04:51 PM

It sounds like Garrett is a step ahead of me, wish I had had his advice when I did my job. "Oh well."

punkinfair · #8 07-24-2007, 09:38 PM

i just did this also. the motor was very dirty inside with crusty rusty grease.

one thing i found out that might be of interest is that the motor itself is identical to ones used on similar vintage vw and audi cars, which also use cable type regulators. all but the outer housing (the part on top of the cable) is identical. it is very simple to take an audi regulator and scavenge the motor. i have a VW parts business and had some new audi units on the shelf. rather than mess with the old unit i wanted to use a new motor. i was able to make a motor swap in about 20 minutes, taking the audi motor out of the regulator. the power wires had to be moved over from the old motor to the new, but aside from that the two motors are indentical brose/bosch units. this would make junkyard picking better also, more vehicles to choose from.

the new motor/regulators for the rear are frightfully expensive and only available as OE parts, glad i saved myself about 400 bucks by going that route.

justinperkins · #9 07-24-2007, 10:09 PM

Quote:

Originally Posted by punkinfair

i just did this also. the motor was very dirty inside with crusty rusty grease.

one thing i found out that might be of interest is that the motor itself is identical to ones used on similar vintage vw and audi cars, which also use cable type regulators. all but the outer housing (the part on top of the cable) is identical. it is very simple to take an audi regulator and scavenge the motor. i have a VW parts business and had some new audi units on the shelf. rather than mess with the old unit i wanted to use a new motor. i was able to make a motor swap in about 20 minutes, taking the audi motor out of the regulator. the power wires had to be moved over from the old motor to the new, but aside from that the two motors are indentical brose/bosch units. this would make junkyard picking better also, more vehicles to choose from.

the new motor/regulators for the rear are frightfully expensive and only available as OE parts, glad i saved myself about 400 bucks by going that route.

excellent tip, I've been worried that my motor was fried and it would cost a lot of money to replace. I guess not!

Jeremy5848 · #10 07-25-2007, 02:30 AM

Quote:

Originally Posted by justinperkins

excellent tip, I've been worried that my motor was fried and it would cost a lot of money to replace. I guess not!

If it turns out you need just a motor, I kept the one from my regulator in which I cut the wire.

justinperkins · #11 08-04-2007, 02:21 PM

Quote:

Originally Posted by Garrett90250

To get it out:
Reach way up inside of the door panel and unhook the black clip that holds the white slider captive to the metal window rail.

...

Can I get some clarification on what clip you're referring to and which direction I'm supposed to be able to "unhook" it? Here's a pic from the bottom:

And here's one from the side (shot from the rear of the door):

I'm just not figuring this out at all

justinperkins · #12 08-04-2007, 02:55 PM

OK, I got it. I wasn't reading your post very clear and in those pics I took I had already removed the black plastic clip. I just had to push the large white plastic piece to the left (toward the back of the car) and it came right out.

In removing the motor though I obviously had to take the cover off the window switch pins so I could pull the two that go to the window motor.

I just wanted to make sure my pins look correct, so took a pic.

I'm just not sure if the pins are supposed to match the diagram on the pin cover if I'm looking at it (as pictured) or if the pins are supposed to match the pins if you envision the pin cover being directly on top of the pins?

I guess I'm thinking too hard about this

justinperkins · #13 08-04-2007, 09:44 PM

Yet another follow-up:

Took the motor and assembly completely apart, cleaned the hell out of it and then put it back together (with lots of white lithium grease along the way).

Everything works excellent now