Window regulators, motors - PeachParts Mercedes-Benz Forum

cmac2012 · #1 08-27-2022, 11:53 AM

The driver’s door on my SDL was beat up pretty badly by a thief several years back, he used a crowbar to pry it open so ge could more easily work the wire down in to pull up the knob. He even left the big bundle of wire that he used, it looks like that stiff wire is it is frequently used to hold scaffolding to buildings, you can bend and shape it but it’s still pretty strong.

The door never did close right after, and it gradually got worse.

I found a door at the boneyard on an ‘88 SEL, It opened and closed perfectly. I got it in with some difficulty. The window doesn’t move. Voltage is getting to the contacts, and it reverses polarity just like it’s supposed to. Before I checked that I put jumper cables up to it to see if 12 volts would get its attention. It did not. No sound, nothing. The motor on the door I took out worked but it’s different, the regulator is shaped different and the motor is different.

The same car is still at the boneyard, also an ‘89 SE.

I’m guessing the motors are probably the same on all four doors. One would think one of the rear window motors would’ve gotten much less use than on the driver’s side. And the motor alone is cheaper.

I can only imagine that getting the regulator out is a tad bit tricky, and you cannot access one of the screws holding the motor to the housing with it still in the door. I’ve been trying to find a video on taking the regulator out, you think there’d be one out there. Are there any unusual tricks to it?

vstech · #2 08-29-2022, 10:45 PM

Nah, it’s pretty simple. Take out the retaining bolts on the regulator, lower the motor to get the slide off the glass, and get it out, then unbolt it from the regulator.

cmac2012 · #3 09-29-2022, 08:47 PM

More fun and games with power windows. Both front windows on the 300D have quit working. The driver’s side failed with the window rolled up, the passenger side is down about 3 or 4 inches.

I knew I wasn’t going to be in a good spot to fix it, what was surgery coming up, she was just before I went in I took off the door power and put 12 V to the same fitting on the door (this photo was taken from my SDL). I tried both polarities and the window did not move.

I am assuming that this means that the motor is bad. There was no noise of any kind.

Does anyone know of a way to manually turn the armature without taking the motor out? Winter is coming, the sunroof works flawlessly, I could get by with no window action just by using the sunroof for sudden air inflow.

Sugar Bear · #4 09-29-2022, 08:56 PM

Try striking the motor with reasonable force from a piece of hardwood or a long socket extension, if no success try striking it while power is applied but keep fingers etc. clear of the gears as the motor may suddenly start.

cmac2012 · #5 09-29-2022, 09:14 PM

Quote:

Originally Posted by Sugar Bear

Try striking the motor with reasonable force from a piece of hardwood or a long socket extension, if no success try striking it while power is applied but keep fingers etc. clear of the gears as the motor may suddenly start.

Excellent. Given me my current circumstances I won’t be able to try that fix out for at least two or three weeks maybe longer. But I have time on my hands here in the rehab center so I thought I would do the homework now.

Texasgeezer · #6 09-30-2022, 11:42 AM

You might try connecting a battery charger instead of a battery. The charge voltage is higher and might be enough to get it moving.

I've taken a few motors apart. They appear to be built very well and with good carbon brushes. Wish there was an easy way to clean out the old gear lube and re-lube it.

cmac2012 · #7 10-01-2022, 07:55 AM

I’ll try it. Am out of action for several more weeks, I’ll report back.

Junkman · #8 10-01-2022, 08:57 PM

All motors and window regulators on a 126 are interchangeable if you get the regulator and motor as a unit. They are location specific ie front drivers has to be replaced with a front drivers unit.

That said, hit Theseus up. He was able to fix a window motor on the my old 84SD but I don't remember the details. He's done a lot to it and it's becoming a joy to drive.

martureo · #9 10-03-2022, 11:48 AM

If you need them, I have two w126 front window regulators from an SDL that I parted out.

I still don't have any use for them and you could have them if you pay shipping.

Diesel911 · #10 10-03-2022, 11:32 PM

I would remove the motor and then see if applying voltage makes the motor work.

I did not read the other posts real close. Are you guys applying the voltage to either the motor wires or the motor terminals?

The window motors are not grounded as a starter motor is as part of the circuit. All the voltage goes through the motor wires.

I dried lubricant and what ever gets stuck in the lubricant of the rear end bushing freeze up the window motor. I had to take it apart and clean and re-lube it after which it worked.

I also had a front door window problem, and it turned out the screws on the terminal/junction block were loose.

Junkman · #11 10-04-2022, 12:22 PM

Others have reported that the motor can be taken a part, cleaned with an inexpensive sonic cleaner and reassembled.

Diesel911 · #12 10-05-2022, 11:57 AM

Again, if you remove the motor enough inside the door you can keep it connected to the wires and see if it functions like that. If it functions like that there is also a chance it is the window regulator resistance that is too high for the motor to function.

There is a thermal switch inside of the motor that will keep the motor from working in the face of a high resistance to turning.

vstech · #13 10-11-2022, 12:41 PM

A common issue with window motors is also soda spilled in the switches…
Fairly easy to take apart and clean with water.

vwnate1 · #14 10-11-2022, 06:07 PM

....OIr, _not_ .

In any case, there are two different electric window lifts for the W126 cars, they're interchangeable .

There are also two different motors so count the gear's teeth before buying or accepting a used one .

I too think you should dismount it and bench test, often the electric motor is simply old with worn brushes or more often full of rock hard 35 year old grease. clean it well, soak oil into the bushings and 90 + % of the time it'll work as new again .

*PING* .

ykobayashi · #15 10-12-2022, 11:37 PM

The gears are worn down on some of my regulators in both my 123 and 126.

I’m putting together a TIG brazing set at the moment and I intend to build up the gear teeth with silicon bronze filler rod then file new teeth on the worn down nubs. I kind of came to this after checking out a few JY regulators and seeing their teeth worn down.

It’s an ongoing project, I’ll start a thread when I actually get started. I’m still in the planning stages.