Does anyone know the part no of the vacuum split pieces in the vacuum system?

Are you talking about the 3-way and 4-way connectors under the hood?

3-way 1170781450
4-way 1170780450

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Sam

84 300SD 350K+ miles ( Blue Belle )

yes 4 way and under the passenger footwell 4 way.

Pelican probably has them. Here are some that I ordered for my '81 300SD. They should be the same size I would think.

https://www.pelicanparts.com/cgi-bin/smart/SuperCart-Track.cgi?Order_Id=1490808437-856&command=lookup

These are the leaking rubbers on my 300D:

Yes; about $4 or $5 each at Pelican Parts. Good to support our sponsor.

above the 4 way is the number correct?

Dunno; did not purchase a four way. Check your original four way; sometimes the originals have parts numbers on them.

Vacuum connector; 4-way: 117-078-00-45 (replaces the defunct part number 117-078-04-50).
Vacuum connector; 3-way: 117-078-01-45 (replaces the defunct part number 117-078-14-50).

seems like you don't need it now - but I think there is a 5-way in the lock system somewhere under the carpets which I believe is NLA. However, you can make a 5 way by hacking together 2 three ways.

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Andrew
Montclair, NJ
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1982 300D Turbo
120k
Petrol Blue Green

Vacuum connector; 5-way: 126-805-00-22

Thanks all