Locked up in frustration - PeachParts Mercedes-Benz Forum

devildogdoc · #1 10-20-2004, 12:23 PM

Oh wizened dieselheads.... A question for those of you in the know about 126's, 82 300SD, no door locks. The vacuum pump in the trunk pulls about 5 pounds, my question is this. On the drivers side floor there is a yellow vac. line that goes to the door, just laying there looking at me. Nothing connected to it at all, nor is there anything near it. If I suck or blow, the lock goes up and down, but it will not lock or unlock the rest of the car... I have searched the archives and found no reference to this line or a vac. diagram that shows this.....any help would be appreciated deeply....also have an 83 300D with no motor or trans with perfect interior for sale/trade cheap.....

#2 10-20-2004, 01:53 PM

That line is supposed to be connected to a line coming from the trunk. Haven't had my SD floors apart yet, but what I have seen is that the line comes through from the trunk and it should connect to the left door line with a short piece or rubber line.
The 5 lbs of vac is an indicator that either the pump don't work very well, or that there is a big leak, like the line being parted. Once you get that put together the other doors will start to lock, as long as they are still connected to the left door. There is another vac line coming from the left door lock to the rt and the rear door locks, as well as the gas door. When you turn the lock the left door locks mechanically and the others are sucked close.
I think it would be best to trace the line from the pump, should go up into the cabin on the left side somewhere. It is likely it goes to nowhere. Should be easy enough to get it connected up.

Smooooth · #3 10-20-2004, 02:03 PM

My 126 (300SDL) also has a line going to the trunk keylock/latch. You can lock and un-lock all of the doors from the trunk.

On mine - It looked like multiple people had tried to figure out why things weren't working. Fortunately I had most all of the rear seat out - most all of the front carpets up, and found at least 2 locations where the yellow line had been seperated. From that point I went on a mission and tracked everyone down. Now mine work!!!! Happy Spouse To!!!

Stephen

devildogdoc · #4 10-20-2004, 02:24 PM

Well see that is where I am running into trouble, on the passenger side, I have a manifold that has 3 lines in and one out to the rt front door, but if the drivers door is mechanical then it wouldnt need vacuum unless the lock the trunk locks the doors deal holds true on mine too......

#5 10-20-2004, 02:40 PM

The line coming from the pump should go to the drivers door first. Then split off to the three other doors, the gas door, and yes , to the trunk lock also.
Turning the drivers door lock controls all of the rest. They should all lock once you turn the drivers door lock.
If I am not mistaken, that rt side manifold should have one line coming from the lft door, and it splits to goes to the rt frt door, and to the rt rear door, and to either the gas door, or to the left rear door. Likewise there is likely to be a manifold coming from the lft door that splits the line going into the rt side manifold, and to the lft rear door and to the trunk.
These may be in different orders, but they all will need to be hooked up to the lft door lock. That acts as a vacuum switch for them all.

devildogdoc · #6 10-20-2004, 05:19 PM

see that's where this is getting weird...three lines come from the trunk to a 3/1 manifold, the one going to the front pass door and the other 2 to the rear doors and the other being the supply line from the pump. In the trunk there is a 3 way that splits off of the pump, 1 to the trunk, 1 to the filler door and 1 forward into the cabin to end in the manifold before mentioned... I eliminated that 3 way so all the vacuum should be going directly to the doors but no luck..all the buttons rise and fall as they should when sucked/blown but not off the vacuum pump... and the line on the drivers side is coming out of the door and facing to the rear of the car, but there is no channel for the lines to lay in like on the passenger side......strange stuff...

#7 10-20-2004, 05:23 PM

I will try to take a peek at mine tonight. What you are describing don't sound quite correct. Maybe someone messed it up.

devildogdoc · #8 10-20-2004, 08:19 PM

I appreceiate that Old Deis, I have about had it and have run out of ideas....PO did some really interesting fixes.....

bbeardb · #9 12-30-2005, 07:13 PM

Quote:

Originally Posted by Old Deis

Turning the drivers door lock controls all of the rest. They should all lock once you turn the drivers door lock.

But does the passenger door control the locks at all? My drivers will lock and unlock all, but passenger does not. I would think that unlocking passenger door should unlock all doors. Is my thinking correct?

deerefanatic · #10 12-30-2005, 09:22 PM

Ok guys, you all are right in a way. I have an 82 SD, this is how the locks work.

Drivers front door, No Vacuum! Only electrical for the pump.

Passenger's door: Vacuum from the 3-way manifold on floor by said door. No Electrical Connection!

Rear Doors: Vacuum from 3-way manifold by passenger front door.

Trunk & Gas Door: From 3-way manifold in trunk, No electrical connection!

So you see, the only lock that will control others on an 82 300SD is the front, drivers door. In 84, the passenger door and trunk were added also, hence the vacuum line at the driver's door too. (As the driver's door lock has to be able to be moved when it isn't in the position as commanding lock, a situation that doesn't exist in the 82's.)

So, you have vacuum line from pump to trunk manifold. From there, it goes to trunk lock, gas door, and passenger front manifold. From there, it goes to both passenger doors and the rear drivers door. The front drivers door has a wiring harness that goes to the trunk pump and controls its operation which controls vacuum/pressure which moves locks.

All Clear?