w124 window trouble...
 

Alright, a few months ago, my rear right window started making this funny noise when rolling up or down, sounded like a piece of metal was rotating around and around, hitting stuff inside the door. Well, soon after, the window assay "exploded" in the words of my mechanic, resulting in a $130 replacement of the window assay. Now, my front left window is making a similar metal on metal sound. When you push the window up or down button, the window moves, a little slower than usual, but it makes this metal clanking noise. any ideas what this is? Thanks.

Sounds like it is time for a new window regulator. I would consider it a "medium" diyer task. Inside door panel has to come off to get to it.

Alright, window regulator, could anyone elucidate on what/where it is? And how I would go about taking it out? I have taken off the door panels before to fix annoying rattlings from the wood trim and to stuff fiberfill inside the active bass modules, so that shouldn't be a problem. Any help would be greatly appreciated...

Your problem is quite common on older Benzes. The teeth on the window regulator get chewed up from people holding down the button too long while rolling the window up. The motor is so strong it chews away the last couple of teeth resulting in a nasty rattle when the window is in an up position. I have done quite a few of these on 190E's. The setup should be very similar if not hte same on your car. As far as I remember there are a number of nuts holding the regulator to the inside door frame. Three on the regulator, one to the window and two more to a rail. All are 10mm as far as I can remember. Move the window down until you can see and reach the nut holding the regulator arm to the window frame and disconnect it there. Then Push the window up so its out of the way and disconnect the other nuts and pull the whole unit out.
You will have to remove another set of three (?) nuts to get the motor off of the regulator. Hold on to the spacers. As far as I remember the front regulator without the motors runs for about
$60-80 and the job is fairly easy if you are inclined to get your hands a bit dirty. Putting it back in is a bit tricky since you need to make sure its properly aligned, but basically just a reversal of the removal procedure.
Good Luck!
F.J.