Front passenger window on 126

[Alan]

The front passender window on my 1986 300sdl is stuck closed. This has happened in the past several times. Each time I remove the motor and test it. It works fine. Problem may be at the switch, which could be dirty inside so I will try that next. Still it may be the window gets stuck sliding through the grooves. I recall reading somewhere that the window guides (grooves) can be adjusted. Does anyone know how? or recall the site where this is explained. It is also possible the guides are very dirty/gummy. Even with the motor out the glass/regulator is very hard to move. Cleaning suggestions? Thoughts?

[jim-22]

Isolate problem before blaming the track. The switches are modular. Check that first because it is so easy. Also note, if the switch and motor are working you will hear a very soft humming of the motor if it is a track problem. I also would not rule out an intermittent motor (as was my problem recently). I was able to find a "good" used one for $50. I would bet on the motor from what you described.
Jim

[JPutt]

Sounds like your motor is weak or intermittent as Jim stated. make sure there are no broken or missing joints or nuts that may be causing the system to bind. You would be able to hear the motor humm if so. I recently had the window motor mount bolts pull through the door frame sheet metal causing a loud bang at top and bottom. I fixed with some large washers.

If your tracks are dirty, remove the door panel and scrub the guides with a small brush and mild detergent and then after its dry, spray guides and grooves with some silicone spray using the small applicator tube. This will make it alot easier on your motor.

John

[BENZITCH]

Are the motors in the front and rear doors the same, if they are both for the same side of the car? Say as if they were both passenger side window motors?
Thnaks
Bruce

[jim-22]

I think all 4 are different.
Jim

[Alan]

Thanks for the thoughts. You may be right about the motor. Even when it works I must toggle the switch off and on to get the window down, then about 1/2 way down it slides easily the rest of the way. Going up is no problem, though slower than the other windows. I've removed the motor in the past and used a battery to test it. It does run, but slowly at first and then a bit faster. Got a good source for a replacement motor? Saw the right one (8 teeth) on e-bay for $100 with shipping, but at least it was new.

The rears are different (suprise!) so that's no help. Still I think cleaning the groves might be useful since the window is tough to move when the motor is out. Thanks again.

[Don350SDL]

If a window is hard to move by hand, or is slower than any of the rest, it indicates a need for lubrication. Clean the tracks fisrt, then apply the MB lubricant. Don't use petroleum-based greases, the plastic slider will break in 6 months.

It is possible for a mechanical problem (bent track, worn components, etc) to cause a problem.

In any case, inspecting/cleaning/lubricating the system is a simple bvut awful job, nothing has good access. Flashlights & mirrors are the tools of the day.

The only adjustment in a 126 front window lifter is the angle, I dont recall the procedure but it is very simple, there's a bolt you loosen, you push the glass some way, then tighten it.

As for the switch, remove it, gently pry off the top cover (small screwdriver to pry it obver the 'axles' on the sides), catch the two springs and metal balls that come out. Pull up the U-shaped contacts, polish the silver contacts, and reassemble it. You only need a new one if the plastic is broken.

Don

[Alan]

Thanks for the help. Its not the switch or the motor. It sticks in the track when the window approaches the top. Looks like a good cleaning is in order.

[bfigueroa]

I have a similar problem with a 1990 560 SEC - any tips on removing the driver's side door panel? Thanks Bob

[Don350SDL]

I am certain that info is on the forum somewhere, do a search and re-post if you can't find it.

Don

[bfigueroa]

I did many searches and this post is as close as I could come re: a "hit". Anyone have any guidance re: tips to remove the door panel on my 1990 560 SEC?

Another question, how do you post a new entry/subject on the forum?

Thanks, Bob

[Don350SDL]

How to remove the inner door panel in a 126 S Class coupe (126.045 and similar)
(This is easier with the photos, available on the service CD and WIS)

1. Remove the moulding at the rear top of the door lock side (open the door, there's a kind of plate at the top just above the lock strike - remove 4 phillips screws)

2. Pull off the knobs for the power seat switch. They just pull straight out.

3. Remove the screw on the cover of the seat switch

4. Pry off the surrounding moulding from the power seat switch (a plastic wedge, starting from the 1:00 position, is recommended)

5. Disconnect and remove the cover in the recess of the inner door handle (it's black plastic on my sedan, and it just pries out)(This is the handle you pull to open the door and get out of the car)

6. Remove the screw from the door handle recess

7. Pry off the cover a bit and remove the screw holding the top of the arm rest to the door (Philips #3 size)

8. Unscrew both screws fron under the armrest (get down low, you'll see two holes about 1/2" diameter, the screws are in there)

9. Push arm rest toweards the rear and remove

10. Lift door lining upwards (not outwards!) and remove. BE CAREFUL TO not damage any wiring!

11. Installatuion is the reverse of removal.

Also, be real careful not to tear the plastic inner liner, it peels off with patience. You can buy a new one at the dealer if necessary.

Have fun,
Don

[bfigueroa]

Thanks so much for taking the time to provide the "how to" details. Much appreciated, Bob