Passenger front window not working and stuck in up position on 89 300E. The procedure for regulator/motor removal is described in the MB shop manual, some DIY posts on the web and in the forum. The first step as described by all, however, is to lower the window most of the way so that the set screws on the regulator tray are accessible. Then the window is raised, wedged and the bolts holding the regulator in removed. I've done a search and found no advice on how to proceed when the window is stuck up.

I assume I should remove the five bolts that hold the regulator in and then carefully drop the whole mechanism down. Any hints? This has to have come up before.

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Jim Wiggin
Columbus, OH
1989 300E

Anyone ?

Mine are stuck up too !

:-( neil

This appears to happen when the motor gets jammed at the very end of the rack. If you hold the switch down after the window reaches the top you can actually see the inside of the door flex because of the stress.

I have had this happen a few times. Sometimes it frees itself up after awhile (weather conditions, perhaps?). When it doesn't, I have removed the inside panel, removed the nuts from the lower bolts that hold the regulator in place, and them gently knocked one of the bolts out with a hammer (the stress on the regulator arms will put a lot of friction on the threads). Removing one bolt should relieve enough stress on the assembly to turn the motor and crank the rack back a bit. Then you can bolt it back in and it should work.

Oh, yeah, remember to duct-tape the window to the seals first so that it doesn't fall down when you loosen the regulator.

Jim Wiggin
Columbus, OH
1989 300E

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Jim Wiggin
Columbus, OH
1989 300E

Just realized I am answering my own post from years ago--live and learn. I never did get any hints from anyone and worked through the procedure myself. Just remember the tape.

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Jim Wiggin
Columbus, OH
1989 300E

I jumpered 12VDC from my spare Optima, and tried it in both polarities to no avail.

You must REMOVE the electrical motor from the lifting mechanism in order to get everything out.

I removed all the nuts that hold the window lifting mechanism in place and then gently pried with a plastic wedge the stud closest to the electrical motor.

This allowed me enough room to access the closest of the three 10mm hex-head bolts that hold the motor to the lifting mechanism.

Then using an off-center 13mm-wrench between the stud and the door sheet metal as a spacer, I as able to access the two other bolts which are further back.

Once I removed the motor and all electrical connections, I was able to lower the glass, and take out the lifting mechanism.

The lifting mechanism was stiff with old grease, so I cleaned off all the pivot points with brake cleaner, and lubed with ATF and then some bearing grease and Wurth spray grease.

I could NOT open up the motor to repack the grease (looks like Mercedes stamped it shut, instead of bolts) but I did remove the old grease at the motor gear.

After re-assembling and testing, all is good!

However, just like the disintegrating vinyl wire sheaths in the 1992+ engine wiring harness, all the wiring harnesses sheaths in the door were crumbling away. And this is in a DARK environment with just sun heat.

When I have more time, I'm going to re-wrap these cable bundles, especially at the hinge-points, as I see these areas as potential short-circuit/fire harzards . . .

:-) neil