Window switches problem - Page 3 - PeachParts Mercedes-Benz Forum

Bimmer-Bob · #31 09-24-2017, 09:34 PM

Quote:

Originally Posted by Diseasel300

How easy is the motor shaft to turn? It should be relatively easy. If it seems stiff or it takes effort to turn it, the bearings may be in need of lubrication.

If you take the motor apart, there is a copper ring with a bunch of segments in it that makes up the commutator. On it ride 2 carbon brushes (chunks of carbon).

Take some Q-tips and soak them in acetone and clean up the surface of the copper commutator and the faces of the carbon brushes where they ride on the commutator. Make sure the brushes can freely move in and out of their holders. If they can't, pull them out and clean them with the Q-tips as well.

Before reassembling, clean out the bronze bearing in the end plate with a Q-tip soaked with acetone. It'll be pretty mucky. Clean off the motor shaft where it passes through the bearing as well. Lubricate it with something like Zoom spout oil or 3-in-1 oil in the blue can (will say for electric motors). Make sure to lubricate the felt wick on the motor-side of the bearing as well.

Reassemble the motor and try it again. If the brushes have good contact with the commutator and you got the lubrication done to the motor, it should run fine. There's just not much to it. What tends to burn them out is when the bearings bind up and seize or the windows jam in their tracks and people continue to try to operate them.

FWIW 3 of the 4 motors in my SDL had the same issue you're facing. The 4th was an aftermarket motor and was completely dead. The 3 motors I repaired are still working fine today and are original to the car.

Using the correct oil for lubrication matters too. Don't even attempt to use grease for the bearings. It'll work now, but it won't for long. If you use engine oil, it will attack the brass in the bearings and cause it to wear very quickly. Using a detergent-free oil such as Zoom Spout Oil or 3-in-1 in the blue can will keep it humming along for another 25+ years.

I guess I'm just not seeing all that stuff that you're talking about. There are two Torx bolts that, once removed, allow the two halves to come apart - one "male" end with the worm gear protruding, and then the other "female" half which accepts the worm gear in order to drive the 10-tooth gear. I imagine the male half can be further disassembled, but I couldn't see a way that didn't involve braking the housing somehow.

Diseasel300 · #32 09-24-2017, 09:43 PM

There are a couple of screws on the motor itself that allow it to come out of the housing. It's been >18 months since I've had mine apart, so I don't remember the specifics. The whole worm gear part will pull out of the motor "can". You'll see the important parts inside.

Bimmer-Bob · #33 09-24-2017, 11:24 PM

Quote:

Originally Posted by Diseasel300

There are a couple of screws on the motor itself that allow it to come out of the housing. It's been >18 months since I've had mine apart, so I don't remember the specifics. The whole worm gear part will pull out of the motor "can". You'll see the important parts inside.

Hmmmm. There are a couple of Torx screws as I mentioned, but the housing itself looks sealed. I don't see any other fasteners anywhere else other than rivets.

I decided just to spring for a new motor, because I want to get this done ASAP and move on to bigger projects. The OE part is anywhere from $300-$400, which is crazy. THE OEM Bosch part was discontinued in 2013 and is NLA. eBay is full of salvaged parts that are cheap, to be sure, but could fail tomorrow for all anyone knows. I finally settled on a reman from AutoZone because it should be delivered to my front door by the end of the week, and it was only about $100 with free shipping, a 10% off coupon, and the core charge refund. Maybe it won't last another 25 years, but I suspect I'll have bigger problems before then anyway, lol.

BONUS ROUND! There are a few things I still don't get. One is this extra slider, item #1 in the picture below. It was just sitting there, in the window rail, not attached to anything. It's shown in the EPC diagram - but again, not attached to anything - which is odd - surely it serves some function? #2 is a body-colored vertical rail. Is that just structural reinforcement, or is there supposed to be a slider in there? FOr example, item #3. Clearly some sort of slider, same plastic as the others and greased up the same as well. I found it loose in the bottom of the door. That can't be good, right? lol

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Alec300SD · #34 09-25-2017, 01:47 AM

http://www.w124-zone.com/downloads/MB%20CD/W124/w124CD2/Program/Chassis/72-185.pdf

There are normally three sliders.

The "extra slider" is the front "slide shoe" that attaches to the front lower regulator arm (Fig. 172-29717 by step 6).
It may have been left behind from a prior repair of the regulator arm, and that's probably why you have an extra.
The metal pin that attaches it to the regulator arm is missing.

The rear slide shoe attaches to the rear lower regulator arm (right side of Fig 172-29710 by step 7).

The front and rear slide shoes are attached to your regulator arms, so you can safely remove and discard the "extra slider".

The "mystery slider" is partly visible in the left side of Fig. 172-29710 by step 7.

It ties the rear vertical guide rail to the horizontal guide rail.
It should be re-installed.

The three sliders are also visible in the photo on Post 5 of this thread:
sticky or DIY for front window regulator replacement? - Mercedes-Benz Forum

Hope this helps.

Diseasel300 · #35 09-25-2017, 09:51 AM

That's kind of disappointing about the motor not coming apart. I suspect Bosch changed the design slightly between 1986 and the mid 90s, so that's kind of a bummer.

That curved sliding piece does go in that body colored channel. When I looked up info for my SDL it gave the part number in the EPC for it, but gave no mention where it was installed. Both of mine were down in the bottom of the door, so it took some trial and error to figure out just where they went. It serves 2 purposes - it helps to guide the window and it helps to keep it from rattling or jumping the track when partway rolled down and the door is slammed.

If you have slides that are missing or broken, the extra strain on the motor could be what's been causing you grief.

Bimmer-Bob · #36 09-25-2017, 09:27 PM

Gosh, I feel so dumb! Parts #1 and #2 in the pic above (AKA extra slider and mystery slider) are in fact THE SAME PART, which serves to connect the regulator to the body-colored rail (#3). It broke in half! Which explains why half of it was still captive in the regulator, and the other half, which rides the rail, fell down to the bottom of the door. And also probably explains the extra stress on (and eventual failure of) the motor, as Diseasal300 mentioned. Well, another part to order. Nice to put that one to bed, lol.

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On another note, any suggestions on what to lube up the new motor and sliders with? I've got a little bit of Gleitpaste, some white lithium grease, some graphite powder...and an O'Reilly's in town.

Diseasel300 · #37 09-25-2017, 09:30 PM

Mystery solved. LOL!

I used silicone sunroof grease to lube the tracks in the SDL. Seems to be what Mr. Bergsma recommends as well. I chose it since it won't harden or react with water, so it won't become "gummy" as it ages.

Bimmer-Bob · #38 09-29-2017, 04:54 PM

Well, everything was going great, until this happened:

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Still not sure what went wrong, exactly. Got everything back together and tried raising and lowering the window. I was getting some resistance and binding, and kept disassembling and reassembling - the main issue was how exactly to fit that "sliding jaw" (the so-called "mystery slider" from a couple posts prior). No matter where I put it, it seemed to interfere. I finally just removed it entirely to check if there were any other points where the window was binding. I started to raise the window, everything looked good, and all of a sudden without any warning at all - BOOM! - the glass shattered into a million pieces.

Now that there's no glass there, the regulator moves up and down without any problems, lol. So I know the regulator is more or less assembled correctly. But I still have two problems:

I still don't know exactly how to install the sliding jaw
Broken glass!

Anyone have any insight into problem #1? For problem #2, I found an OE used window for $39. Pretty good deal, but I'm afraid of repeating the experience if I don't get to the bottom of why the glass broke in the first place...

Now, if you'll excuse me, I've got a huge mess to clean up! lol

Bimmer-Bob · #39 09-29-2017, 08:22 PM

Also, is this where the sliding jaw goes? (Obviously the window rail is not pictured)

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It's the only arrangement I can figure out that makes any sense, except that it's impossibly tight, no matter how much you lube up the slider and track. It's going to burn out the window motor in no time if I run it this way.

Diseasel300 · #40 09-29-2017, 08:28 PM

The sliding jaw you show does appear to be in the right spot, although it appears to be a different design than the original one you show further up the page. Are you sure it's the correct part? It should be a snug fit, but not tight.

Before putting in the new window, it would be a good idea to find out what bound up and broke the one you have. I'd suspect it jumped a track!

When they do break, it's pretty alarming. I had a rock come in through my front passenger window in a construction zone once. I thought I'd been shot! Talk about a loud noise! BOOOOOOM!!!!!!!! Had that car for another 4 years and was still finding little shiny diamonds in places when I traded it in...

Bimmer-Bob · #41 09-29-2017, 08:43 PM

Quote:

Originally Posted by Diseasel300

The sliding jaw you show does appear to be in the right spot, although it appears to be a different design than the original one you show further up the page. Are you sure it's the correct part? It should be a snug fit, but not tight.

Thanks for the input. I'll double-check the part number - maybe I somehow got a sliding jaw for another chassis?

Quote:

Originally Posted by Diseasel300

Before putting in the new window, it would be a good idea to find out what bound up and broke the one you have. I'd suspect it jumped a track!

All the plastic sliders are still in the appropriate tracks. The sliding jaw was not in place, and the window was about 3/4 of the way closed when it broke. I'm thinking it was not aligned correctly because the sliding jaw was removed - either that, or one or more of the regulator arms are bent or something. I haven't removed the regulator yet to get a good look at it.

Quote:

Originally Posted by Diseasel300

When they do break, it's pretty alarming. I had a rock come in through my front passenger window in a construction zone once. I thought I'd been shot! Talk about a loud noise! BOOOOOOM!!!!!!!! Had that car for another 4 years and was still finding little shiny diamonds in places when I traded it in...

Yeah, it was momentary alarm followed by immediate regret, lol. I cleaned up most of everything except all the glass that is within the skin of the door. Gonna have to be real meticulous about that so the damn thing doesn't sound like a maraca every time it slams shut.

My whole day was ruined - was going to put my BMW on jack stands and drain the engine oil and transmission overnight, but now I don't have the garage space to do so (don't want to move the Mercedes outside with a broken window because it's been raining off and on). Oh well!

Diseasel300 · #42 09-29-2017, 08:54 PM

The window should move up and down freely in its tracks, even if the sliding jaw isn't installed. I haven't worked on a 124, but the 126 has tracks in the doors that the window glass rides in. It's very easy to get the front edge out of the track, especially if you've been fiddling with the window. When you try to roll it up, it will bind, if you don't catch it, it doesn't take much to shatter the glass.

I mention the design of the sliding jaw since it looks different than the one you removed. The new one I bought for the SDL looked exactly like the broken one you had. It would make sense that it would be a tight fit if the one you have now is designed for a different chassis.