I dont understand what that means when you guys talk abou it, about door locks and things like that, does the SD have power door locks?

Its a pump that sucks...

Sorry,couldn't pass up the opportunity.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

What is the perpose of the pump??

Just like steve wrote, it is a pump that either sucks (to lock the doors, trunk and gas lid) or pushes air to unlock those items.
I do not know if your model has one, but my car has it under the back seat - passenger side.

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1999 Porsche 996 Carrera Convertible
1994 420E - SOLD
1986 300E - SOLD, what a car
609 Certified

To make vacuum.

Diesels have no manifold vacuum as gas engines do. That is because they have no throttle plate (atleast not since the 76 240D). Vacuum is used to add power assist to brakes and control numerous actuators.

There is a pump driven by the motor for brakes, AC, and vacuum shut-off. The SD (depending on year) also has an electric vacuum/pressure pump for the door locks.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Well mines a 83 (if you couldnt tell Benzinit83)

Actually I couldn't tell. I understand names like George and Sue, I don't look to a gibberish name to describe the content necessary to interprete a post.

My flip first answer had a lot to do with the lack of information presented in the question.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Lack of info? What dont you understand about "what does a vaccum pump do"?

Geez and your a moderator, Pathetic

What car, what system, would be nice. Really depends on the depth of answer you wish. Based on your confusion I can see my first answer was suitable.

There are a few on this site who actually can give answers that depend on what car you are talking about. The fact you have atleast two vacuum pumps on that car DEPENDING on what it is, means decent questions will get decent answers.

If you don't know that you need to describe your car and system in technical questions maybe your post shouldn't be on a technical forum. Try dear abby.

BTW, I moderate the tech only section and then only as a volunteer. I don't owe you anthing!! I am very happy to ignore your posts if that is better for you. I only answered it cause it had dropped half way down the page with no response. I'll do better next time.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Ahha LoL, Imsorry if i afended you, al i know is that its a 83 300sd, auto, cc, pw and everything else taht seems standard.

Will a turbo diesel produce some vacuum when the turbo is spinning? It seems like it would?

Also, as fas as I can tell, a gas engine is given air when you put your foot on the gas, and the amount of fuel necessary is then added (metered). With a diesel, your foot sends the engine fuel. Is this (basic) description correct?

And finally, exactly why does a diesel engine produce no vacuum?

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'90 300SE 298k
-300K and it gets put into retirement.
'80 300D 255k Purchased new by family in 1980.

Had a:
1973 220 (gas)
1980 300SD
1992 400E

BeNzInIt83......without knowing it, you insulted perhaps the most knowledgable person (there are many others, I know) about MB you will ever find....here or anywhere else. If I were him I wouldn't give your future posts a second glance. Grow up.

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1996 SL320 97K miles
1996 C220 130k miles
1992 500SEL 170k miles <---sold
1986 300E 216k miles <---sold

There only would be vacuum between the turbo and the airfilter if the airfilter acted as a throttle (plugged). The air between the turbo and the intake valve is under some amount of pressure boost if the turbo is spinning up.

And finally, a diesel exactly doesn't have intake vacuum because it has NO THROTTLE plate (since 1976 240Ds).

Take a straw, put your finger over the bottom, suck, your have manifold (straw vacuum). Remove the throttle plate (your finger), suck, do you achieve any vacuum? In a gas engine speed is determined by the amount of air. By placing a plate in the stream restricting the flow the engine sucks as in the straw case against your finger. BTW keep your hands away from the intake of a running diesel you might wind up coming out the exhaust, boy can they suck.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Its called sarcasm buddy, so dont even take it seriously, Stevebbfl if i did affend you than i offer you my sincierest appolygies (i know i cant tspell)

Pet pieve, proper ID, complete questions. I'll get over it, sorry to bully the point.

While I'm pointing it out. I'm also picky about salutations. I receive a lot of email. I'd rather that, than phone calls, but I occasionally loose email so write me back (if I haven't replied in a day I am out of town or the email was lost in the spam I get, about 300 a day). But if you don't sign your email that will be the first reason I don't reply.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician