I just joined the MB world with a 1984 300D that I really dig! It's my first diesel and I love it, I also have a ton to learn. I bought this car before I really new what I was looking at. That being said, after brining it home and starting to look at other MB's I noticed my engine was missing something.

I am missing the vacuum block that attaches to the throttle linkage. A day latter I found the old linkage with the vacuum hoses attached in my trunk all balled up!

The seller told me the doors didn't work because a vacuum leak, so they plugged the tubes that ran to the cabin for that. The AC doesn't work, not sure if that is a symptom of the vacuum thing or not. It shifts O.K., sometimes is shifts a bit slow though.

My real question is what is that part and what does it do? How does the car operate correctly (more or less) without it? Where can I find a complete vacuum system diagram?

I have the Hayes manual and I have the shop manual on order. The Haynes manual did not call out that specific part.

it attempts to control vacuum to the transmission. bypassing it is a good thing.
but it needs to be done correctly.
search here for egr remove or somthing.
google.com advanced search with this site as the location is much better than the search button. (thanks Brian!)
John

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Agreed!

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83 SD

84 CD

I believe on your car the "block" you mention is only for the EGR. Most folks have blocked off/disabled the EGR system due to the extreme carbon buildup it causes in the intake.

Here is a vacuum diagram link:Vacuum Diagrams

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Sam

84 300SD 350K+ miles ( Blue Belle )

Alright, that makes me feel better. At least I know the car's not going to start choking on me.

It'll take me a bit of time to figure those diagrams out. Thanks for the tip!