Hi, all-

I was removing the door liner on our 1991 300D 2.5 a few weeks ago. Never having done it before I didn't realize how careful you have to be when removing the large "bottom of the seat" button from the switch. (I couldn't find a discussion of this anywhere on the CDROM, by the way). I pried it at one corner and snapped the large square stalk off the sliding plastic plate. For the record, try to pry it straight out as gently as possible...

Not wanting to spring for $75.00 for a new switch, I tried fixing it. I removed the switch from the door and pried out the brass retaining plate with jeweler's screwdrivers. This allowed me to get the flat plastic plate out. I tried gluing the stalk back to the plate with JB Weld. This worked for a week or two but the bond between the very thin plastic plate and the stalk was weak and it snapped.

I wasn't ready to give up yet. The black mercedes switch plastic looked like ABS (the same stuff used for black plastic sewer pipe). I had some Ace Hardware ABS cement around so I decided to try that. After removing the plate again and cleaning off the JB Weld (it didn't really stick very well), I glued it back on with ABS cement. The particular brand I had seems to be ABS plastic dissolved in some sort of solvent (smells like Methyl Ethyl Ketone).

After a few minutes it was clear that I was on the right track. After the solvent evaporated it left behind what looked like virgin Mercedes switch plastic. I even was able to create a missing piece by making a mold of masking tape and wiping some ABS cement into it from the back side.

I let the repaired switch stalk dry overnight and installed it this morning. We'll see, but It seems pretty much as good as new to me. Here's a photo:



Max Behensky

1982 240D
1991 300D 2.5

Both running on biodiesel.