W123 electric vacuum pump guys, check in.. - PeachParts Mercedes-Benz Forum

wolf_walker · #1 03-29-2004, 11:09 PM

I know there a couple of you here that have put a pump on your w123 for the locks. Check in here, share any more tidbits of info.

I'm planning on the second door switch deal at the moment to trigger the pump.

It would be kind of nice to trip the pump to vacuum when the door lock actually moves, but I don't know that it's worth the effort.

I think one could completly convert to the w126 setup if they wanted to spend the time on it, single line vacuum solonoids, etc, etc. I'm pretty content with the idea of just haveing limitless lock/unlocks. The large vacuum resouvour should be an asset to this as well, pump should be seldom needed.

Any clue at what vac the pump kicks off at?

BoostnBenz · #2 03-30-2004, 03:20 PM

There is a link on my site that links back to a member's conversion to electric vacuum pump here if that helps.

#3 03-30-2004, 07:20 PM

I have the electric setup. My pump does not have the auto-pump function, I set it to pump to 12" every time the driver door is opened. If I had a D or CD I would also put a fairly large vacuum tank in the trunk to help it last even longer. But, having a TD, I'm lacking any space to hide it.

By having an electic pump run the doors and ACC I found the engine pump can make the transmission shift much better by having a constant and fast reacting vacuum supply. (I still keep the vacuum from the modulator because I like firm shifting much better.)

wolf_walker · #4 03-30-2004, 08:24 PM

I experienced the more consistant shifting once when I had my door locks unhooked while waiting on a part. I want that back, the less variables the better. I'm also going to make a try at retrofitting the 85+ blue vacuum transducer to give a little more load sensing to the whole shifting deal.

I've got a pretty good sized resouvour and already am good for 5-6 lock/unlock cycles right now. I think for simplicitys sake the door switch method will do. Any clue what vac reading the pump kicks off at?

How loud is the pump under the dash like that? I have the foam football it was mounted in from the SDL doner, figured I'd stick it somewhere in the trunk. It was inaudable in the SDL.

Seems like there was one other person that gave me an explination of how they did this once, but I can't find the thread?

#5 03-31-2004, 06:57 PM

I can get 5-6 cycles with the stock tank behind the fuel tank (Pop quiz: How much volume does this vacuum tank hold?). The only auto-pumping unit I had was from a 380SE and it was too gunked up with rust to use. The one from the '84 SD must have had a remote pressure sensor to activate it. (It shuts itself off with a clunk at 12")

The loudness is fine for me (I like to hear what my car is doing). Once the engine is on, it's hard to hear unless you listen for the specific sound. With the engine off, it is fairly loud and can hear it humming while outside the car.

It only takes about half an hour to make a simple setup and the better transmission shifting alone is worth it.

wolf_walker · #6 04-01-2004, 04:08 AM

It occured to me this evening that with the remote keyless entry I have I should be able to trigger the pump with the door lock solonoid's current. Slightly less wireing, and it will run the pump if I say, open the rear door or trunk.

I think one day if I keep this car, or any w123, I'll be converting it completly to the later w126 system with a single vac/pressure line to each solonoid, and the sensing solonoids so as to allow interlocking from the trunk and either door. But the pump alone will do for now..

If I can ever find time to work on the damn thing..