Hi there, Anyone out there with knowledge on how to remove the vacuum element(?)- the thing that pulls on and pushes the door lock mechanism, of which there are one for each door? (an 85 300TD Wagon)
I seem to be in a rut. It seems to have a leak but I'm trying to remove it and cant seem to figure out where it would disconnect from the mechanical lock rod thing. There seems to be a plastic slider that sort of clicks in and out of place if I pull or push on the whole assembly (once the holding screws have been removed of course) but from there I cant seem to get my hand to feel anything that can disconnect or unscrew.
The vacuum hoses are easy enough to disconnect but now trying to disconnect the element from the mechanics is tricky. The ones in the side doors are much more accessible but not sure how to get around this one.

Grasp the rod itself and pull it so as to extend the vacuum solenoid/operator, with the other hand push the end of the operator at the point where the rod attaches it the opposite direction. The end of the operator has a concentric ring at the end of the rod's connector that will move backwards snapping out of place and you will be able to see the threaded portion of the rod and the inside operator's rod attachment parts.

It is deceptively simple but elegent design once you understand how it operates.

The amount of rod threading which is engaged in the operator's rod attachment part is one of the adjustablity points, the other is the positioning of the vacuum solenoid/operator. Good luck!

Thank for the info. I couldn't quite figure out how to do it yet. Here I attached a couple pics. When you refer to the Solenoid operator I assume you mean the rubber plunger-like part that will squish up and down according to open or locked vacuum action right? I get a little thrown off when you mention using the other hand. It seems hard to get even one hand in there. Im not sue how to get two. Should I stick a pair of pliers through one of the holes in the door body? using the pictures and my chicken scrach sketch of whats behind the door, could you tell me if you mean to hold on to the rod part that is in between the "plunger" (as described in the pic) and the plastic piece? (#3 inside door pic)
The plastic part seems to slide extending and reracting if I pull or push on the assembly hard enough. I dont want to break anything though. I cant see any threads exposing when I extend it. Any help would be a godsend.
Thank you.

Attached Thumbnails

   

When I replaced this I found it helpful to have the new one in one hand and then I could see how the old one was attached. It's been a while but I don't recall it being terribly difficult, I just removed the mounting screws and let it swing around until I could wrangle it free.

Getting the new one up in there is tricky then you have to snap the fitting at the end into the hole (#5 on your diagram) - I used a screwdriver to do this through the cutout in the door (IIRC). On mine this was the part which had broken off anyway so getting the old one out wasn't the issue - it was getting the new one to snap into place.

Don't overthink it but I would suggest having a replacement in-hand too. Since they aren't serviceable you will be looking at replacing it anyway. Look at the photo in this listing and maybe you can understand more about how it fits:

http://catalog.peachparts.com/ShopByVehicle.epc?q=&yearid=1985%40%401985&makeid=63%40%40MERCEDES+BENZ%40%40X&modelid=6234%3AMBC|1518%3AED|10000135%40%40300TD&keyword=door&subcatid=P:241806@@Door+Lock+Actuator&mode=PA

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

Great, Thanks I think I got it now. Ill see what I can do. Any Idea now on how to remove the lock assembly. The lock seems to have stopped accepting my key. it feels almost as if the pins are all seized and the key slides in and out without any resistance from the pins. It looks pretty dusty in there and I would like to clean it up and oil it but my Hanes manual doesnt go in to much detail at all about how to get it out. It goes as far as saying remove the lock mounting bolts and remove lock assemblyu through the hole. pretty vague. I cant seem to see any bolts that look close to the lock tumbler/assembly that would let it loose. Perhaps Im wrong though.
Thanks again.

Don't oil the lock. Use graphite powder. In my experience blowing powder into the lock is enough to lubricate it without requiring disassembly.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13