Window not working...what is this??

[johnny tron]

Hello all,

This week the driver side window on my 1978 300cd stopped working...I thought it was the regulator but once I got everything off there was a clean break here that you can see in the picture, (it's a bit dark but you should be able to see where it's broken on the piece sticking out to the left....)

Any help on this would be greatly appreciated!

[BWhitmore]

The break is not surprising. These regulators were not the strongest and are known to break like this especially the rear windows in a coupe. I have also seen the front windows like your's snap the regulator. The proper repair is an unbroken regulator from a wrecked car.

[Marrs]

I don't have this model so forgive my ignorance but is that cast metal or plastic? If it's plastic I'd imagine it is only a matter of time before metal 3d printed versions of these are produced or even a more durable plastic.

[Idle]

You will have to replace it. Metal fatigue is the cause of this break and there is nothing you could do to prevent it.

Place an ad in the 'parts wanted' section of this board. Someone might have a parts car or know where one is.

Another thing to consider is if this part is unique to the Coupe. Could it be the same as any other 123 with the exception being the length of the arm?