Here are pics of the pump and switch I bought. Still showing in ebay for me (dunno why).

Still under $100 with a relay added, I'm sure I can get the pump cheaper at a pick n pull it's just that I'm in nowheresville so the hour or so ride each way to a boneyard usually isn't worth it.

Edit: $50ish for the pump, $30 for the switch. Several used pumps of this type are on ebay right now in the $47 to $59 range (and higher). I'm sure if I could find the switch somewhere other than ebay or an EV site it would be a good bit cheaper.

Edit Edit: For those with unlimited dosh and no sense of adventure, a compleat kit: http://www.amazon.com/COMP-Cams-5500-Electric-Vacuum/dp/B001O0685G/ref=sr_1_1?ie=UTF8&qid=1380213747&sr=8-1&keywords=comp+cams+brake+vacuum

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Eric, CPO, Submarines, retired.
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Mine: '68 Corvette LS1/4L65E, 83 240D, 2000 GMC 4x4, 08 FLSTC Anniv
Hers: '72 Corvette 454/4spd, '99 MB SLK, '93 Metro vert, 78 240D, '92 Silverado, '65 Fjord Rustang, '59 Fjord Fairlane, '17 Slingshot.

I spent about those same amounts on my setup. Still less than $300 for a mechanical pump. Even if it cost the same, removing the motor-destroying ability of the mechanical pump is worth it to me.

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617 swapped Toyota Pickup, 22-24 MPG, 50k miles on swap

motor destroying, and I'd expect the HP to create the electricity is less than that require to drive the mechanical pump, although I have a stock alt.....

I have several 'parts' Saabs here in the back field and heard a rumor that those alts may be an upgrade. Might have to explore that since they are free.

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Eric, CPO, Submarines, retired.
Here's a sig line...
Mine: '68 Corvette LS1/4L65E, 83 240D, 2000 GMC 4x4, 08 FLSTC Anniv
Hers: '72 Corvette 454/4spd, '99 MB SLK, '93 Metro vert, 78 240D, '92 Silverado, '65 Fjord Rustang, '59 Fjord Fairlane, '17 Slingshot.

Looking forward to seeing how your vacuum switch works out. Mine is whonky and will need to be replaced.

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617 swapped Toyota Pickup, 22-24 MPG, 50k miles on swap

If you don't need the Vacuum for anything else but the Brake Booster have you tried tapping into the Brake Light Switch (only if you have a Relay to the Vacuum Pump).
The idea is that the Brake Light turns on the Vacuum Pump.

I have not tried this so I am not sure it will build up Vacuum fast enough like that.

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84 300D, 82 Volvo 244Gl Diesel

If my pump was big enough and I had a decent reservoir, I think that would be fine. As it is, my vacuum pump runs a good bit when I first turn on the key, runs a bit when I push the brake pedal and then shuts off, and then runs again when the brake pedal is released.

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617 swapped Toyota Pickup, 22-24 MPG, 50k miles on swap

Is the built in reservoir supplying the brake booster or the other vacuum things in the car?
I see a white plastic check valve on the main line to the booster where the line to the reservoir comes of. How does that function?
I have the Volvo rotary vane pump now and need to get an adjustable switch.
Is there an easy place to pickup the key on power for the relay?
Thanks experts.

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1984 300SD turbo 126
"My true love"

God made me an atheist and who am I to question His wisdom

If your Vacuum Pump Failed to out vacuum or the line broke before the white Check Valve I believe I read you get 3 pedal applications before you lose the Power to the Power Brakes.
The Check Valve tries to prevent that sudden unexpected loss of Power to the Power Brakes.

If you have an Electric Pump line the one in the Pic without a Vacuum Shutoff Switch the smooth Steel top gets hot enough to blister your.

When I had Mine on the Car I did not have Vacuum shutoff Switch so when you install Yours please let Me know if the Vacuum Shutoff Switch controls the heat on that Pump.

The Locking System has a big Reservoir above the Fuel Tank on the W123s and had separate Check Valves from the Brake Vacuum.

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84 300D, 82 Volvo 244Gl Diesel

The Vacuum shutoff Switch is critical.
Without one in the circuit, the pump runs all the time = overheating.

.

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1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

https://www.boldegoist.com/

That is entirely reasonable.

What I am interested in is that On the Volvo it is listed as a Brake Booster Pump but also some of what I have read said it was to assist when the Manifold Vacuum was low. That could mean it is not meant to run as often as I might think it does.

And, on the Mercedes with an Automatic Transmission even with the Vacuum Shutoff Valve it is going to run more than it would on a Gasser due to the Vacuum Valve on the IP.

So I am curious to see how hot the Pump gets on the Mercedes application.

Also buyers of that type of Vacuum Pump need to be careful they get the Euro made Pump.
GM uses a Pump that looks exactly the same but it is made in Mexico.

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84 300D, 82 Volvo 244Gl Diesel

Well, my Saab version of the pump arrived, as did the switch. Since I now have the Euro 240D the electric vac pump project is moving to that car since it's only going to power the brakes and shutdown.

I bought two different style vac sensing cutoff switches. Assuming I get enough driving time I'll be testing both out, but I don't drive that much these days so it may be awhile before a report on switch #2, especially if there are no issues with the first style.

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Eric, CPO, Submarines, retired.
Here's a sig line...
Mine: '68 Corvette LS1/4L65E, 83 240D, 2000 GMC 4x4, 08 FLSTC Anniv
Hers: '72 Corvette 454/4spd, '99 MB SLK, '93 Metro vert, 78 240D, '92 Silverado, '65 Fjord Rustang, '59 Fjord Fairlane, '17 Slingshot.

I had no Vacuum Switch but when I drove around with My Volvo Vacuum Pump (made bye Hella) connected to test if using it was feasible everything that used Vacuum functioned the same.

So I don't think you will have any problems.
Electric Vacuum/Brake Booster Pump Tested

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84 300D, 82 Volvo 244Gl Diesel