What does this do?

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cpg003
Dernburg Wagon
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What does this do?

Post by cpg003 » Mon 11 Jun, 2018 9:14 am

Morning all,

Can anyone give me some clarification of what this is and what it does? It’s mounted underneath the coolant reservoir of my C107 and has two vacuum lines and an electrical connection attached. Thanks in advance.

Ignore the writing on this one, just a pic I found on eBay.
Pierburg Vientil pressure regulator DB2097 ZK 12982 8171
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1979 450 SLC - C107 - Milan Brown
2017 220d GLC - W253 - Polar White

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John Green
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Re: What does this do?

Post by John Green » Mon 11 Jun, 2018 6:49 pm

Idle speed adjustment when the A/C compressor cuts in. It interrupts the vacuum to the ignition distributor.
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cpg003
Dernburg Wagon
Posts: 8
Joined: Fri 06 Apr, 2018 7:34 am
Model you own: w107
Region: Western Australia
Location: North Perth

Re: What does this do?

Post by cpg003 » Mon 11 Jun, 2018 7:57 pm

Thanks John. Much appreciated.
1979 450 SLC - C107 - Milan Brown
2017 220d GLC - W253 - Polar White

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Chai
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Re: What does this do?

Post by Chai » Wed 04 Jul, 2018 8:28 pm

Those with too much time on their hands can clean the very fine metal mesh that acts as an air filter in that part. The filter is located at the top of the unit (yellow looking item in the photo).

The filter in my 40-ish year old unit was partially clogged with dust. The tip of a needle can be used to poke out the debris (I did say ... too much time in my hands).

The air-leak to the vacuum line connected to the distributor when the air-conditioner is switched results in the cancellation of the distributor retard (i.e ignition is advanced and engine revs up).
Chai
1974 450SLC

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Astro-Benz777
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Re: What does this do?

Post by Astro-Benz777 » Wed 10 Oct, 2018 8:01 am

Chai wrote:
Wed 04 Jul, 2018 8:28 pm
Those with too much time on their hands can clean the very fine metal mesh that acts as an air filter in that part. The filter is located at the top of the unit (yellow looking item in the photo).

The filter in my 40-ish year old unit was partially clogged with dust. The tip of a needle can be used to poke out the debris (I did say ... too much time in my hands).

The air-leak to the vacuum line connected to the distributor when the air-conditioner is switched results in the cancellation of the distributor retard (i.e ignition is advanced and engine revs up).
Thanks Chai, I think you've just given me my next mini-project!
W126's truly were the last real Benz in my opinion! :occasion5:
FORMER FAMILY:
1989 300SE (W126) Midnight Blue, Blue/Grey Interior (Gearhardt)
1982 380SE (W126) Thistle Green, Tan Interior (Sherman)
CURRENT DAILY DRIVE & BELOVED FAMILY MEMBER
1984 280SE (W126) Thistle Green, Tan Interior (Hilda)

Djenka018
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Re: What does this do?

Post by Djenka018 » Thu 11 Oct, 2018 11:43 pm

Another interesting fact about this part is that it has vacuum "polarity" meaning it is a 'changeover' valve and it maters which hose goes where.
'80 450SLC 3-continental

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Astro-Benz777
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Re: What does this do?

Post by Astro-Benz777 » Fri 12 Oct, 2018 12:46 am

When my Benz came back from a local repair shop after an incredibly unfortunate incident in a shopping centre carpark (a lady reversed out of her carpark without looking & straight into my passenger side front guard/fender), they did a great job repairing the panel damage but.... it came back with all of the vacuum lines to the left side (basically ALL of them) disconnected.
Sooner than take it back and let them blindly attach them to whichever line looked like it fit (I assumed the reason they hadn't reconnected them was due to not knowing what to reattach them to).... Through help from the forums, general knowledge from the service manuals, trial and error and sheer luck, I managed to reconnect them all correctly.
They might not seem important but the vacuum polarity, being correctly connected & leak free really are vital to one's Benz running smoothly, correctly & giving it a long and healthy life.
W126's truly were the last real Benz in my opinion! :occasion5:
FORMER FAMILY:
1989 300SE (W126) Midnight Blue, Blue/Grey Interior (Gearhardt)
1982 380SE (W126) Thistle Green, Tan Interior (Sherman)
CURRENT DAILY DRIVE & BELOVED FAMILY MEMBER
1984 280SE (W126) Thistle Green, Tan Interior (Hilda)

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