It is impossible to determine the condition of a vacuum pump from a picture. If the pump has in excess of 200K miles, it needs to be replaced with a new pump. Rebuilding a pump costs the same as a new pump and is certainly not as reliable as a new pump. From the pictures posted it appears that the engine has not been treated to regular oil changes at 3,000 mile intervals. You might want to read the posts on this forum about what happens when a vacuum pump explodes internally - quite often it will destroy the engine camshaft, timing chain, cam towers, etc.

Thank you, I'm reading into it.

That is the "piston" vacuum pump. I would guess the piston ring is torn, letting engine oil past, and unlikely you had any vacuum produced. I bought the rebuild kit for ~$105 on ebay a few years ago. It comes w/ a new piston ring, 3 small check valves, and the rubber gasket seal. As I recall, the ring is a rubber O-ring with a Teflon U-sleeve you slide over it. I recall the old seal was something like leather. You will also need another outlet fitting/check valve. Most engines you see in the junkyard have that part removed (darn cherry pickers).

The 2nd rebuild kit mentioned is for the rolling arm. The failure concern is the 2 ball bearings that support the roller. You can find posts w/ PN's. Best idea is to replace with metal-shielded bearings that can't fall out. In my 1985, the bearings failed so the arm was dragging and half cut thru. It was making a noise, but my son had it out of town and drove ~100 miles. Once the arm cuts thru, it slides into the timing chain and *&%!. The balls seem to have slid thru with no problems (haven't found them, but didn't remove pan yet).

__________________
1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

I haven't had too much luck sourcing rebuild kits for the piston style vacuum pump. I'm going to check WorldPac for some rebuild kits, if I can't find any it'll look like a new vacuum pump sound be in order.

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Ok so you have described the issue I am having with my newest addition to the family of benz's I have. my 1983 300CDT- ( I also have a 1981 300CD non-turbo, 1983 240D and 2- 1983 300DT sedans!)

I was curious to what progress you have had in fixing your problem. THANKS in advance for posting this.

Hi almater!

I haven't been able to pin point exactly what failed within my vacuum pump, it could be a number of things. I believe it to possibly be:

1. One of the three internal check valves has failed, not allowing vacuum to be created.

2. The piston seal failed, which is not allowing vacuum to build up any more.

I've order a new Genuine MB vacuum pump from a guy on eBay (eBay name is "partscontainer"), and am still waiting for it to show up, once it does I'll let you know if it fixed it. I also am curious to the exactly component that failed, and will find a way to test them and post my results!

I've tried to find rebuild kits, or an affordable source for new piston kits, but was without luck.
PeachParts looks to be the most reputable (and affordable) seller of new piston style vacuum pumps. Avoid the sketchy eBay sellers, the seller I'm dealing with is a nightmare.

I also have a WorldPac (massive parts distributor for shops) account through my work, and the new vacuum pumps from an OES provider is showing to be NLA. So get em while you can!

New genuine vacuum pumps from the MB Classic Center are around $360 plus shipping.

So my Vacuum pump came in, the eBay seller ended up sending me a BMW M10 OIL PUMP. YAY.

So my new pump will be here next week, and I'm going to be installing it that weekend. Anything I should check before installing it?

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Got it in, I'll be going for a line drive to make sure all is fixed!

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How did it go?

__________________
1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
********************
1979 240D 140Kmiles (bought for parents) *SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD

I've got about 1,000 miles on this pump and it is functioning perfectly!

Great !

__________________
1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
********************
1979 240D 140Kmiles (bought for parents) *SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD

Always nice to hear of happy endings ! .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

If our vacuum pumps get orphaned someday, there are 2 alternates. One is an earlier diaphragm pump (2-tubes), for which rebuild kits are still ~$10 last time I looked. Another is using a used electric vac pump from a newer diesel (VW, Audi). Several here tried that with mixed reports. Some said it ran too high a duty cycle (did they have a leak besides the normal VCV flow?).

__________________
1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans