300CE window regulator teeth wear
 

anyone have an idea why the 124 coupe - 300CE window regulators all seem to go bad, wiping out the teeth at the end of the run, up position? a friend of mine just bought one of these cars, an '88 300CE and both window regulators are bad, the passenger side especially. the teeth on the driven half-circle gear wear out and the window will not lift all the way. i searched this forum and lots of people with the same issue. the image shows typical wear, however this one is not far gone at all. on my buddy's car the teeth are completely worn off. it's almost as if there is something wrong with the mechanism and instead of stopping at the extremes of motion, the motor starts to skip on the teeth and after a while they wear to the point of not working at all.

i am going to replace the regulators on the car and i am curious if anyone has done anything when replacing the regulator to try to prevent the issue from happening again. i see there is an adjustment stop for the regulator, is this adjustment part of the issue?

also, thanks to member jt20 for the photo.

Its a coupe issue for sure. Look how long the door is and how heavy that glass is. The teeth and motor are the same in the other 124's. Just chalk it up to oops the germans wernt thinking on that one. Alot like my wifes ML320 and the do not use dino oil recall in them.

yes it makes sense that it's a flaw in the manufacturing design of the regulator, too many failures for it to be otherwise.

Those regulators fail on the shorter sedan windows too. Bad design perhaps, but the soft steel used is a culprit too. It allows too much flex and the gears wear against each other. Changing them is a right of passage for some of us.

Speaking of these coupe regulators, does anybody know if the front's are the same as their sedan/wagon counterparts?

no the coupe is a different regulator.

That's what I thought, but the motors are interchangeable I'd assume.

My gear is stripped at the top of the window movement in my 124 wagon. Any way to buy less than the full assembly offered above?

Yes they should be more robust. The life of the regulator can be extended by not running the window completely closed at speed so everything is under tension. Run one all the way and watch how everything gets under tension. Release the button JUST before complete travel and lightly tap the button to raise it the rest of the way. When the car is stored release the tension by tapping the button downward.