240d Vacuum line help -- what is green/yellow?

Hi all:

Today's project is getting the power locks to work again so coffee is in hand and the door is apart.

There are three lines coming in to the master vacuum switch; yellow, orange/yellow, and green/yellow.

The green/yellow circuit does not hold vacuum. Does anyone know where to go "next" on this circuit starting at the master switch?

Many thanks!
sga

[JimmyL]

Well, that is different color coding than my 300TD. Look under the driver's carpet, right at the door sill side, and the lines should run from the master vac switch down to there.
From that point, if like 300's, it will branch off, and one set will go to rear driver's side, and the other will go to the passenger side stuff, fuel door and trunk lock.
My assumption is yellow if main vac supply, and the other 2 are "lock" and "unlock" circuits....

**edit**
BTW, at first, just measure/test vac from these sections under the carpet. There is another junction under the passenger carpet. I didn't pull any door panels off until I knew that the vac TO that particular door was faulty....
I had a bad trunk lock diaphram on the 240, bad rear driver's door lock on the wagon if I remember correctly.....

Looks like you're right ... there's a "lock" circuit, I think on orange/yellow, and an "unlock" circuit on green/yellow. Both pairs go to all doors & the trunk lock.

If I take the trunk lock out of the system it holds decent vacuum so that's a Good Thing (tm)!

More later as this saga unfolds ...

[Biodiesel300TD]

You got it. Yellow/orange (yellow/red usually) is the locking side, and the yellow/green is the unlock side. There is another set if T's under the carpet on the passenger side that controls the passenger side doors, the fuel door and the trunk lock. You just have to work your way down the lines until you find out which is leaking.

This might help as well, a guide for troubleshooting yor vac system - http://www.schumanautomotive.com/forums/showthread.php?t=2755

[Shorebilly]

Folks,
I have mentioned this li'l grey book before.....it's not a repair manual, it is a reference book designed to be used by service techs, and kept in their toolboxes....there is a wealth of info in the 500+ pages.....

I quote page #483
Color Code of Vacuum Lines:
Models: 107 (3rd version) and 123 (2nd version)

Suction Line from Engine to 1st Distributor.......................Grey
Suction Line from Distributor to vacuum Storage Tank........Yellow-Grey
Line to Vacuum Switch.................................................Yellow
Locking Line................................................................Yellow-Red
Unlocking Line.............................................................Yellow-Green

There is also a chart listing "permissible" leakage in 1 minute in mbar (millibars) ......I did not bother to type that chart because I don't feel like explaining/converting metric vacuum.....

SB

[MBeige]

This is the diagram I made. On mine the orange was actually yellow, so I just coded them accordingly.

Yellow - yellow
Red - yellow/red or orange
Green - yellow/green
Gray - gray

I don't recall which one was yellow/gray, I think it was the one going to the rear vacuum reservoir. The diagram was for a wagon though, should be similar with the sedan.

Here's another diagram:

http://home.comcast.net/~phantoms/vacuum/interlock_system_layout_1_0203.jpg

[Shorebilly]

.....although I am not working on the locking system, and mine works well....one never knows....and I didn't have that diagram......at lease I don't think so, I have not seen it in the MB W123 Service Manual CD, but I have never looked around in this area......saved it anyhoo.....

SB

[Biodiesel300TD]

Originally Posted by Shorebilly

Folks,
I have mentioned this li'l grey book before.....it's not a repair manual, it is a reference book designed to be used by service techs, and kept in their toolboxes....there is a wealth of info in the 500+ pages.....
SB

What is the title of this wealth in info?

[Shorebilly]

Originally Posted by Biodiesel300TD

What is the title of this wealth in info?

As I wrote in the header....

Technical Data Passenger Cars, April 1985 Edition......got it from MBUSA.....Classic Center......Technical Literature.....

SB

[NLatkovic]

When I bought my 1982 240D, the green yellow stripe line was disconnected with the vac side line blocked with a screw.

Could not find info on vac system so I hooked it back up - keep in mind car and locking system were fine. What could possibly go wrong?

The line controls the gas flap and to my wife's dismay, engine shut off. Needless to say I disconnected it again. Maybe trunk is affected as well.

[pj67coll]

Originally Posted by NLatkovic

When I bought my 1982 240D, the green yellow stripe line was disconnected with the vac side line blocked with a screw.

Could not find info on vac system so I hooked it back up - keep in mind car and locking system were fine. What could possibly go wrong?

The line controls the gas flap and to my wife's dismay, engine shut off. Needless to say I disconnected it again. Maybe trunk is affected as well.

If the gas flap is affected the trunk likely will be as well as they lines split at the gas flap and terminate at the trunk lock.

- Peter.

[okyoureabeast]

Originally Posted by NLatkovic

When I bought my 1982 240D, the green yellow stripe line was disconnected with the vac side line blocked with a screw.

Could not find info on vac system so I hooked it back up - keep in mind car and locking system were fine. What could possibly go wrong?

The line controls the gas flap and to my wife's dismay, engine shut off. Needless to say I disconnected it again. Maybe trunk is affected as well.

What was I doing in May of 2007?



I was finishing up high school, had a great girl friend ,and didn't know I loved wrenching on cars.


Sigh that was 12 years ago.

[vwnate1]

Craig ;

That link doesn't seem to work, mayhap you could copy & paste the diagram/image ? .

There's a specific order to testing the central locking, it begins under the hood and takes a little bit of time but isn't really difficult if you have a MityVac tool .

[optimusprime]

Go to Google search . On Google serch page look up to your r/hand side you will see images now click on images .In the image search box put in -Mercedes W123 vacuum diagram. But lots of info on this forum a page of vacuum diagarams from members .