vacuum system - 84 vs 85 300D - Page 2 - PeachParts Mercedes-Benz Forum

tobybul · #16 10-18-2006, 04:11 PM

Quote:

Originally Posted by rmarzan

Here is a shot of my Federal 300D, The "four way" connection that's questioned on your first pic has a brown vacuum line and a green vacuum line connected to it and leads to the main brake booster line via the port nearest the firewall.

Take a look at the pics and I hope that helps.

Richard

your pic shows that all connections in the 4-way are used. But Sam's diagram shows only 2 are used. Is yours an 85?

DeliveryValve · #17 10-18-2006, 05:14 PM

Quote:

Originally Posted by tobybul

your pic shows that all connections in the 4-way are used. But Sam's diagram shows only 2 are used. Is yours an 85?

It's an '84.... In your pic of the 4 way connection, you are missing the brown line and the line to the vacuum booster.

Richard

tobybul · #18 10-23-2006, 12:41 PM

Please see the first post on this thread. Would appreciate help. Thanks.

tobybul · #19 10-25-2006, 09:19 AM

does anyone know where I might be able to buy this connector? Am sure the dealer has it but any online parts place. I surfed many of the mb part places but seem no luck.

#20 10-25-2006, 09:25 AM

I think this is what you are looking for:

http://catalog.eautopartscatalog.com/mercedesshop/sophio/quote.jsp?clientid=catalog.mercedesshop&cookieid=1CQ0J3JZ41XG0K5RGR&baseurl=http://catalog.peachparts.com/&partner=mercedesshop&year=1984&product=B2025-15633&application=000004966

tobybul · #21 10-25-2006, 10:11 AM

Quote:

Originally Posted by Craig

I think this is what you are looking for:

http://catalog.eautopartscatalog.com/mercedesshop/sophio/quote.jsp?clientid=catalog.mercedesshop&cookieid=1CQ0J3JZ41XG0K5RGR&baseurl=http://catalog.peachparts.com/&partner=mercedesshop&year=1984&product=B2025-15633&application=000004966

I have seen this in various online parts stores but for some reason I cannot see its picture. Do you? the only one I saw is this from ******** but not what am looking for.

Samuel M. Ross · #22 10-25-2006, 12:00 PM

Quote:

Originally Posted by tobybul

I have seen this in various online parts stores but for some reason I cannot see its picture. Do you? the only one I saw is this from ******** but not what am looking for.

... it is a standard 4-way "cross" style rubber connector that has been bent/deformed to look as yours does [ like a "pitchfork" ]. On one of our MB(s) we found plastic clips being used to hold what were "cross" 4-way connectors in this configuration and I think you could use a plastic electric tie for the same purpose. Does this clear up this easy to have confusion about this common style rubber vacuum connector??
Just in case you have not seen this idea, take a look at this photo: http://ericandkat.com/mercedes/W123VacDoorLockDiag.JPG which illustrates a technique my private MB mechanic showed me for closing up small vacuum leaks in such connectors... those that are maybe a little loose but NOT yet completely dried out and cracked.
Regards,

tobybul · #23 10-29-2006, 07:15 PM

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=330042361783&category=43991

I bought a brand new unit from AZ for $29.99....

tobybul · #24 10-30-2006, 10:42 AM

I recently purchased 3 books from **************.com related to vacuum system troubleshooting for my 1984 300DT. I believe my problem may be simple but there are some details I could not find in the books. I will say that the books are helpful overall. Good pictures.

Mainly, my central lock system does not work. I believe I have isolated the problem to just the yellow/grn line that starts from 3-way chk valve located by the brake booster going in firewall. This is the only line that does not hold vacuum (it holds vacuum when the drivers door is in the locked position). This tells me that the problem is past the drivers door or the master vac valve.

So, my guess is it could either be a leak in the line or in one of the actuators. At this point I am not clear on how to test the actuators. There are 2 connections to each actuator. How am I to know if its bad? (I have a Mityvac vacuum tester and also a separate vacuum gage tester). My vac pump is working at about 23 in hg.

Samuel M. Ross · #25 10-30-2006, 11:59 AM

Quote:

Originally Posted by tobybul

I recently purchased 3 books from **************.com related to vacuum system troubleshooting for my 1984 300DT. I believe my problem may be simple but there are some details I could not find in the books. I will say that the books are helpful overall. Good pictures.
Mainly, my central lock system does not work. I believe I have isolated the problem to just the yellow/grn line that starts from 3-way chk valve located by the brake booster going in firewall. This is the only line that does not hold vacuum (it holds vacuum when the drivers door is in the locked position). This tells me that the problem is past the drivers door or the master vac valve.
So, my guess is it could either be a leak in the line or in one of the actuators. At this point I am not clear on how to test the actuators. There are 2 connections to each actuator. How am I to know if its bad? (I have a Mityvac vacuum tester and also a separate vacuum gage tester). My vac pump is working at about 23 in hg.

I believe you already have my Door Lock System vacuum diagram that's posted at: W123 Vacuum InterLock Diagram OR can be accessed direct at: http://ericandkat.com/mercedes/W123VacDoorLockDiag.doc
Also let's clarify that your 1984 "300Dt" is what I know by reference as a 300D Turbodiesel and that it is a 123 chassis MB??? IF not, my diagram might not be of much help. For the sake of helping you BEFORE I leave the country on Wednesday for 3 weeks, let's assume the above is correct.
Advice/Comments:
First a question... Q1 - Did you also check the yellow-dark stripe vacuum line under the hood that comes off the same check valve as the solid yellow line [runs to driver's door]. This is to the reservoir tank in the trunk and is more easily tested with a T, run the engine, and then watch it to see if the vacuum drains away too quickly [ should hold overnight IF not days].

(1) The Yellow-Green vacuum line you identified supplies vacuum from the driver's door vacuum "Key-Switch" to: both right side doors, the left rear door, the fuel tank door, and trunk... and this LOCKs these doors.

The following will allow you to further isolate the problem without taking the 3 door panels off [in the blind!].

(2) Under the floormat of the driver's seat under a plastic shield I believe you should find two 3-way rubber vacuum connectors. You might have to break away plastic fasteners and then replace with stainless steel sheetmetal screws afterwards. There should be a 3-way rubber vacuum connector with your yel-grn lines that run: (a) from the driver's door switch, (b) to left rear door, and (c) to the right side of the car below the floormat of the front passenger's seat. Using your hand vacuum pump test (b) and (c) above and see which is NOT holding a vacuum. IF (b) go there and remove the door panel [ somewhere on the FORUM there are THREADs on this subject].
IF it is (c), then go to (3) below.

(3) Under the floormat of the front passenger's seat you should find another plastic shield with two 4-way vacuum rubber connectors. The one with the yel-grn vacuum lines should include connections: (a) from the line from the driver's door 3-way connector, (b) to running forward and to the right front door, (c) rearward to the right rear door, and (d) rearward to both the fuel door and trunk lid vacuum actuator. Using your hand vacuum pump test (b), (c) and (d) above and see which is NOT holding a vacuum. IF (b) or (c) go to the indicated door and remove the door panel.

Enough for now... just in case I have gone off on a tangent needlessly!
Something in my gut says you will also find a leak in the reservoir line/tank/grommet/connector! Report back soon or I will escape to Italy on ya!
Regards,

tobybul · #26 10-30-2006, 12:40 PM

Quote:

Originally Posted by Samuel M. Ross

I believe you already have my Door Lock System vacuum diagram that's posted at: W123 Vacuum InterLock Diagram OR can be accessed direct at: http://ericandkat.com/mercedes/W123VacDoorLockDiag.doc
Also let's clarify that your 1984 "300Dt" is what I know by reference as a 300D Turbodiesel and that it is a 123 chassis MB??? IF not, my diagram might not be of much help.

Yes, its turbo 123 as you described

Advice/Comments:
First a question... Q1 - Did you also check the yellow-dark stripe vacuum line under the hood that comes off the same check valve as the solid yellow line [runs to driver's door]. This is to the reservoir tank in the trunk and is more easily tested with a T, run the engine, and then watch it to see if the vacuum drains away too quickly [ should hold overnight IF not days].

I believe I have also isolated the reservoir tank. Thats one of the first things I looked at. I applied pressure to this solid yel line and it held vacuum. Didn't even show any loss after I pumped it to 20 inches. This leads me to conclude that my line to the reservoir is tight! I actually started checking the connectors you described on the drivers side floor but stopped short as I had to do something else.

Enough for now... just in case I have gone off on a tangent needlessly!
Something in my gut says you will also find a leak in the reservoir line/tank/grommet/connector! Report back soon or I will escape to Italy on ya!
Regards,

Thanks for your very thorough reply!! I was only asking about how to test the actuators because this was one of the things suggested by the book I was using.

tobybul · #27 10-30-2006, 12:43 PM

Sam, also, should the doors be in the unlock position when I am doing these tests??

Samuel M. Ross · #28 10-30-2006, 01:02 PM

Quote:

Originally Posted by tobybul

Thanks for your very thorough reply!! I was only asking about how to test the actuators because this was one of the things suggested by the book I was using

... you can do this withOUT removing the door panels by going to the 3-way and 4-way connectors under the front driver's and passenger's floormats/plastic shields and using your vacuum hand pump alternately pump up the yel-grn and then yel-red vacuum lines going in/to each of the 3 doors. The yel-grn line to the trunk lid/lock also goes to the fuel door actuator so if this does not hold, then it could be either fuel door or trunck actuator. This also means there is a "T" connector in the yel-grn trunck line that branches off to the fuel door. This "T" is accessible from the trunk near to where the fuel door is located. You have to remove the trunk wall liner piece. The yel-red line that goes to the trunk lid actuator ONLY goes to the trunk lid actuator.

As you pump vacuum into the green and then red lines for each of these, you are in essence testing the actuators and the button on the door should rise and fall. The trunk is a little more of a task for you have to go back and check both trunk and then fuel door after you pump up the green line [to lock] and then the red line [to unlock]. Happy testing!

Once you are adept at removing door panels without breaking too many of the plastic fasteners [ buy at least 6 to use as replacements/spares]... once you are adept at this, you should go into the 3 doors, remove the actuator from the door [noting where the green and red lines are connected] and then clean the rubber covers over the actuators [for trunk and fuel door too]... clean them with a soft brush [old worn out tooth brush works] ... clean with "Armor All" (sp?) or other rubber/vinyl cleaner/preservative.
Regards,

Samuel M. Ross · #29 10-30-2006, 01:10 PM

... where you said:

Quote:

Originally Posted by tobybul

[COLOR="Blue"][B]...
I believe I have also isolated the reservoir tank. Thats one of the first things I looked at. I applied pressure to this solid yel line and it held vacuum. Didn't even show any loss after I pumped it to 20 inches. This leads me to conclude that my line to the reservoir is tight! I actually started checking the connectors you described on the drivers side floor but stopped short as I had to do something else..

To be certain about this... as I show on my diagram, on my two W123 chassis 1980(s) the solid yellow goes to a check vavle near the steering column under the dash and then to the 2-way vacuum key switch in the driver's door.
It is the yel-dark stripe vacuum line that goes ONLY to the reservoir.
Regards,

tobybul · #30 10-30-2006, 01:35 PM

ok, I'll chk them tonight. Actually, all the door panels are off the door. I got the car this way a few weeks ago as the PO was trying to diagnose the same thing.

I'm beginning to understand the vac system on these cars a bit more and am optimimistic that the problem is close in sight. Thanks for being accessible to help.