Hello everyone,

I am working on doing a moderate overhaul of the front seat mechanisms in my 1986 300SDL. I looked for a forum specific to interior work, didn't find one. Dear moderator, if this posting needs to be moved, have at it.

I thought I would share some pictures of what I am encountering so those of you that want to try some of this can get a head start.

The first picture is the passenger seat on the workbench with the back cover off. There are only two screws which hold the seat back cover on as marked. My reason for going into the seat back is that the headrest motor makes a whirring sound when you power it but the headrest does not move. The two black runners you see in the picture are where the two headrest posts slide up and down and are held in place.

The headrest motor has a short drive shaft over to the...well... I guess you would call it the headrest drive transmission, although I hesitate to call it a transmission. There is a nylon box that houses the drive gear which is turned by the drive shaft. When this gear is turned, it drives a nylon rack (just like rack and pinion steering) which moves the headrest up and down.

So my first question. Is the short headrest drive shaft supposed to have a black jacket like the ones under the seat have? If so, mine is missing.

My second question. Refer to the attached picture showing the two headrest rails from the side. The rail that holds the headrest drive mechanism appears to be slightly bent inward (towards the seat back) when compared to the other rail. Is this correct? I am thinking that this bend could be a cause of my broken pinion housing.

The next photo is the rack and pinion drive for the headrest, removed from the seat.

And the final photo is showing how my pinion housing is broken Does anyone know where I can get one of these?

Attached Thumbnails

       

__________________
Mike Frederick
1986 300SDL, 240K+ miles
1985 300D KaliKar, 270K+ miles