I searched but found nothing on this:

My 300SD engine vacuum pump had I think 3 plastic one way valves
inside the pump last time I took it apart.

In my observation all that was wrong was the plastic valve finally disintegrating.

When I look at $300 rebuild kits I do not see the little plastic one way valves.

The other option is the $400 pump in complete form.

I will likely start scavenging junkyard pumps for these internal parts.

I did check/install the one way valve that is inline and is metal outside the pump.

Does anyone here know or agree with what I am describing ?
The plastic one way valves that allow the pump to actually pump and hold vacuum.

So why can't we purchase these valves alone by themselves ?

__________________
80 300D 340K Owned 30 yrs
83 300SD 440K Owned 9 yrs - Daily Driver 150mi/day
02 Z71 Suburban 117,000
15 Toyota Prius 2600 miles
00 Harley Sportster 24k
09 Yamaha R6
03 Ninja 250

This thread will probably be a very nice read for you.

More than you are likely to ever want to know about OM61X piston vacuum pumps

I don't know if it answers the questions you have, but it might and it's full of very valuable info.

__________________
'84 190D 2.2 5MT (Red/Palomino) Current car. Love it!
'85 190D 2.2 Auto *Cali* (Blue/Blue) *sold*
http://badges.fuelly.com/images/sig-us/302601.png
http://i959.photobucket.com/albums/a...0/sideview.png

Do a search for Mercedes vacuum repair on eBay
These kits are for a different pump but contain the valves that you're looking for.
I believe the little internal valves are interchangeable between pumps.
If that's all you need then these kits may work for you

That certainly is the best complete explanation of a pump for sure.

But regarding those 3 valves, they are treated as something incidental.
A lot of focus on the bearings.

In my case, those three little round valves that are referred to in just about the last couple slides are my primary concern.

If I could purchase those 3 little round one way valves, all my problems would be solved.

__________________
80 300D 340K Owned 30 yrs
83 300SD 440K Owned 9 yrs - Daily Driver 150mi/day
02 Z71 Suburban 117,000
15 Toyota Prius 2600 miles
00 Harley Sportster 24k
09 Yamaha R6
03 Ninja 250

The kit you described is probably for the rocker arm.
That one is pricey and doesn't include any valves.

Mercedes Benz Vacuum Pump Repair Kit 0005864043 | eBay

THATS IT!
I agree that they are probably interchangeable.
That link says 240D but not the 300D or 300SD.

And the link only shows 2 valves, a 300SD pump has 3.
Which is okay, I will just buy two kits.

__________________
80 300D 340K Owned 30 yrs
83 300SD 440K Owned 9 yrs - Daily Driver 150mi/day
02 Z71 Suburban 117,000
15 Toyota Prius 2600 miles
00 Harley Sportster 24k
09 Yamaha R6
03 Ninja 250