If I can do it without the massive edukation then you should be able to do it. There is really nothing tricky about it.

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1977 300D Lost coolant while someone else was driving
1983 300D Can't run without oil
1985 300SD (gone but not forgotten)
1990 300TE 4matic Sold
1991 Yamaha Venture
1975 Kawsaki 250 triple
1974 Honda 200CL
1951 8N Ford
2008 Wildfire 650C

I'm an accountant and I rebuilt mine. So it should be a walk in the park for an engineer. (Yes, I did conduct a cost/benefit analysis before deciding whether to replace or rebuild.)
But before you order the overhaul kit, I would suggest that you confirm the proper operation of the check valve that is contained in the fitting (nipple)where the booster line attaches to the pump. You can remove it with the pump still installed on the engine. A failure of that check valve can produce symptoms almost identical to a failing vacuum pump.
If you decide to o/h the pump, make sure to procure a replacement pump-to-engine gasket, as it is not part of the o/h kit.
You might find this helpful:
http://207.210.95.34/~boostd/easley/Rebuild_vac_pump.htm

I am willing to bet 35 cents that the 3 vacuum pump valves located behind the plate closest to the engine fan either are bad or need to be cleaned. I would also bet that your vacuum pump check valve is bad (located on the pump housing and connected to the main vacuum line).

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1984 300D / The only Benz I have

Completed weekend projects

1. R/R front crankshaft seal
2. R/R nearly the whole vacuum system
3. Converted to WVO www.greasemachine.com
4. Upgraded to electric power locks
5. Upgraded and rewired stereo/amp/speakers
6. Installed 2.88 differential

Started to pull apart the vacuum pump and found that the main check valve is gone. What happens to the check valve bits when it comes apart? Are the pump internals toasted when the check valve comes apart?

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'82 300 TD Wagon (China Blue)
'99 Ram 2500 Cummins Turbo Diesel

If you do a rebuild you will find the guts of the check valve. Don’t worry about the check valve chunks. They are sold and far to big to cause any problems. Replace that check valve and the other valves I mentioned above and call it a day.

__________________
1984 300D / The only Benz I have

Completed weekend projects

1. R/R front crankshaft seal
2. R/R nearly the whole vacuum system
3. Converted to WVO www.greasemachine.com
4. Upgraded to electric power locks
5. Upgraded and rewired stereo/amp/speakers
6. Installed 2.88 differential

Thanks brabus. Are the other check valves supplied in the rebuild kit?

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'82 300 TD Wagon (China Blue)
'99 Ram 2500 Cummins Turbo Diesel

The check valves inside the pump are in the kit. The external fitting is not. So you need to obtain the o/h kit, the "nipple" check valve, and the pump gasket.
However, if your pump is pulling 18" hg without the check valve, my bet is replacing the valve will solve your problem.

Like the other guy said. Just the 3 valves underneith that plate held in with screws are in the rebuild kit. That one connected to the main vacuum line is a big chunk of green. I recomend replacing all of them. like I said i got 35 cents ridding on this, so you can be fairly sure I want to win.

__________________
1984 300D / The only Benz I have

Completed weekend projects

1. R/R front crankshaft seal
2. R/R nearly the whole vacuum system
3. Converted to WVO www.greasemachine.com
4. Upgraded to electric power locks
5. Upgraded and rewired stereo/amp/speakers
6. Installed 2.88 differential

I know it's been a few years, Don'tdoit, but I'd be interested to hear how your rebuild project went.

Cheers,
Bradley