"Hen's tooth" 1985 300D vacuum filter dark black
 

Vacuum filter dark black, (Fuel filter Purolator# F21124) ...

This was the only warning before the vacuum pump failed.

The piston shaft threads stripped, the nut worked down the shaft until it broke the vacuum pump cover.

Repair required locating a used pump at the local salvage yard.

The only other option was to buy a new vacuum pump.

PART NUMBER SEARCH RESULTS WITH PRICES
Vehicle 1985 Mercedes Benz 300D Turbo
Part: Diesel Vacuum Pump
D3000-11694 Diesel Vacuum Pump Pierburg IN STOCK

http://catalog.peachparts.com/item.wws?sku=D3000-11694

what? i have one of those filter things on a vac line ...

Yes
 

Between your oil filter housing and brake master cylinder.

:eek:
I don't have a filter like that. From the picture, I can't really see what line its supposed to be on...I can see its under the five-legged octopus. I'm guessing I should add one though, can someone describe what vac line should have the filter, please?
Thank you.

I have three of them all set to put on, I just need to get some hose/clamps....I think I'll do that today! :eek:

Seems too be the season for V/P failure. Those inline filters seem like a great idea. I'm going too buy a sack of them and put them on all my cars.

Have you ever had too replace that bushing on the intermediate shaft ?

I have one of those between the fuel pump cutoff, going into the cabin...it hasn't been replaced in ever, as far as I know, only a few specs of oil on it.

I was wondering where to find one of those. Why is this a sign of impending failure?

The one in your pictures looks like it's in the VCV vent line. The one in my '85 just runs into the cabin.

Jeremy

Mines about out but i stripped the bottom hex bolt on the cover i have yet to get it out 25 yrs of crud makes things difficult sometimes :(

that bottom hex is a notorious "stripper";) It was probably half stripped by the last guy before you started on it.;)

Answer
 

Engine oil entering the vacuum system =
* Failing vacuum pump
* Damaged injection pump vacuum shutoff valve

Normal functioning vacuum system flow:

* Vacuum pump, removes air from the system, pumping air into the crankcase, (Good = 28 - 30 inches mercury), (minimum = 13 inches mercury).

* Check valves, and pump piston seal prevent engine oil being sucked into the vacuum system after engine shutdown, wear/age causes slow failure = small amounts of engine oil entering the vacuum system accelerating system failure.

* Damaged injection pump vacuum shutoff valve diaphragm, this circuit is in vacuum during and after engine shutdown = small amounts of engine oil enter the vacuum system, gumming up check valves, degrading all rubber parts, and accelerating system failure.

Engine oil is near impossible to clean out of the system.
Installing this filter on the shutoff valve is smart, adding others for climate control, and W123 central locking system can not hurt, and may prevent a large mess...

I am a little confused about how this filter comes in contact with oil if it gets in the system. One end is incoming fresh air (or engine bay air) and the other is the vacuum side of the system.

Clarity: in the California system (I know..), the filter Tees out and is not in series with anything but fresh air. Although, mine is completely black. And some of my tubes are as well.

Answer
 

Your filter is different, it is a vent filter.

The filter shown is between injection pump vacuum shutoff valve and vacuum source tube.

thank you. I feel much better.