reconnecting with my vacuum valve

[ricardon5945]

This question is regarding my 1980 300TD (na). @ 300K give or take
In doing some routine stuff under the hood today, I noticed that the rod from the throttle linkage that goes to the vacuum control valve- I think this is what it's called- on the top back of the injector pump- was disconnected.
I'm hoping that this explains my 1-2 shifting problem and is an easy fix!!!

My problem is that I can't quite figure out how the linkage is supposed to connect. It looks like there are remnants of some plastic part on the end of the rod. And I assume something goes through that little hole on the valve. I've searched around here but haven't found enough info.

Anyone know what part I need to replace or if I can just rig it back together?
What I'd really love to have is a picture of what the connection should look like so I don't put it back together wrong.

Thanks!!!
Christine

[Samuel M. Ross]

Originally Posted by ricardon5945

This question is regarding my 1980 300TD (na). @ 300K give or take... In doing some routine stuff under the hood today, I noticed that the rod from the throttle linkage that goes to the vacuum control valve- I think this is what it's called- on the top back of the injector pump- was disconnected. I'm hoping that this explains my 1-2 shifting problem and is an easy fix!!!
My problem is that I can't quite figure out how the linkage is supposed to connect. It looks like there are remnants of some plastic part on the end of the rod. And I assume something goes through that little hole on the valve. I've searched around here but haven't found enough info.
Anyone know what part I need to replace or if I can just rig it back together?
What I'd really love to have is a picture of what the connection should look like so I don't put it back together wrong....Thanks!!! Christine

On the WebSite http://www.peterschmid.com there is an option in the left sidebar menus that is titled " Vacuum control... Valve Test" and this will lead you to a 7-page description of a test that requires specialized equipment. A couple of important things here for you to read/see/understand is what is shown on page two at:
http://www.peterschmid.com/vacuum/1977_1985/trans_only/vac_p2.jpg where they show you two different versions of what you are calling "...the rod from the throttle linkage to the VCV..." except in these test instructions the rod is called the "Push rod". The adjustment procedures in these instruction are also helpful.

Also, to specifically address your hard 1-2 shift problem, take a look at my THREAD at:
http://www.peachparts.com/shopforum/diesel-discussion/167513-try-%93dashpot%94-your-pre-1981-auto-mercedes.html#post1307281.
I recommend you test and install one of these little green vacuum chambers between the VCV[#65] and SwitchOver Valve[#64]. These # references are from what I believe to be the correct vacuum diagram for your car and it is available at:
http://www.peterschmid.com/vacuum/1980/617_912.jpg
Regards,

[bgkast]

All of that vacuum stuff that connects to the injection pump and throttle linkage controls the EGR, which is an emissions device. If you do not have emission testing or inspection where you are I suggest you disable it. Try a search for more information.

[ricardon5945]

Thanks for the input-
I went back out this morning and the clip was actually still on the rod..just took me a minute to figure out what it was supposed to be doing. So I think I'm all hooked up again. Unfortunately, stupid me, I left the key turned in the ignition overnight and drained my battery so no test drive yet.

Bgkast:
From the searches I did yesterday I understood that the VCV controlled the vacuum to the transmission modulator. And that it is another vacuum valve on top of the valve cover that was for the EGR...correct me if I'm wrong- maybe understanding all the vacuum stuff will be my next project.

Hopefully once I get her started, she'll be in good shape again-

[JimmyL]

Originally Posted by ricardon5945

Bgkast:
From the searches I did yesterday I understood that the VCV controlled the vacuum to the transmission modulator. And that it is another vacuum valve on top of the valve cover that was for the EGR...correct me if I'm wrong- maybe understanding all the vacuum stuff will be my next project.

Hopefully once I get her started, she'll be in good shape again-

I think you have the correct understanding of your system. There are many different systems and components utilized in the W123 production line, which dieselly (new term) uncluded 240's, 300D N/A, and 300D Turbo. Some folks, myself included, don't know the finer points of all of them. All you can do is research the exact type you have, and re-ask questions if an answer doesn't seem to apply. Sounds like that is exactly what you did...............
Now, get that car listed in your signature. Quick..........

[ricardon5945]

Yay! transmission is back to normal-what a relief.

So I learned 2 lessons today. 1) that the simple design of my car is truly a thing of beauty and 2) that MB roadside assistance will come and give me a jumpstart for free whenever I need it!

Thanks for everything this site is the best!
Christine

[Samuel M. Ross]

Originally Posted by ricardon5945

Yay! transmission is back to normal-what a relief. So I learned 2 lessons today. 1) that the simple design of my car is truly a thing of beauty and 2) that MB roadside assistance will come and give me a jumpstart for free whenever I need it!
Thanks for everything this site is the best!
Christine

... you don't get to go home just yet... you gotta put some closure to this here drill you just put us through. We want you to give us a final summary of just what all you finally did to solve your problem... and tell us what stuff/procedure we gave you was most helpful.

We need this for posterity and the ARCHIVEs so others will benefit!

Also, don't forget what I wrote earlier in this THREAD:
"Also, to specifically address your hard 1-2 shift problem, take a look at my THREAD at:
http://www.peachparts.com/shopforu...81#post1307281.
I recommend you install and test out one of these little green vacuum chambers between the VCV[#65] and SwitchOver Valve[#64]. These # references are from what I believe to be the correct vacuum diagram for your car and it is available at:
http://www.peterschmid.com/vacuum/1980/617_912.jpg"
A DashPot costs ~$5.00 and has really improved the 1-2 shift on both of our 1980 models.
Best Regards,

[ricardon5945]

Well, Sam, it's really not all that exciting, just a minor victory for my wallet and my peace of mind and a better knowledge of my car (I'm just learning). Literally, I took another look at my connecting rod, push rod- whatever- and the little plastic clip was not what I thought it was supposed to look like- it was the second style in the VCV test link you posted- so it was actually intact and I just snapped the thing back onto the VCV. Not sure how it came loose in the first place... maybe I bumped it changing the oil filter...??.

I did read your other thread and the connected articles and I have a much better understanding of my vacuum system and transmission so thanks for all the info. At some point I will address the vacuum leak in my climate control system but maybe not till spring- The heat still works well.

[Samuel M. Ross]

Originally Posted by ricardon5945

Well, Sam... I did read your other thread and the connected articles and I have a much better understanding of my vacuum system and transmission so thanks for all the info. At some point I will address the vacuum leak in my climate control system but maybe not till spring- The heat still works well.

Well I hope you now more fully appreciate the resource you have in this FORUM such that you will be more confident you can deal with more and more complicated issues with the help of the many experienced people who participate here. When it comes to the " Environmental " system on these vintage cars [ A/C, Heat, & Fan ] I will be a student right along with you with maybe only a little more confidence due to my graying hair!
Best regards,