Boycott vacuum go electric!!!
 

I hate vacuum leaks, with a passion. I've started wondering just what it would take to convert most of the vacuum actuators over to electic.

vacuum pump
brake booster
transmission modulator
door locks
shut off valve
HVAC
seat back locks
reservoir

Can't reasonably get rid of the brake booster, so we need to keep the vacuum pump too.
The tranmission modulator turns throttle position into a pull. Sounds like you'd need a rheostat, controller and position sensitive motor. Little involved, so probably keep it vacuum.
Door locks - can you say solenoid? Add one switch in place of the master vacuum switch and your set.
Shut off valve - solenoid.
HVAC - lotsa solenoids. 5 micro switches.
seat back locks - 2 solenoids.
reservoir - who needs it?

Anyone made an attempt at this yet?

I am all electric on my locks and all manual on the HVAC
Jake

Can you post a few pics of the locks? I'd love to see your solution.

I installed a solenoid on the drivers door for my alarm, the rest of the doors are controlled by the vacuum, which is controlled by the drivers door. It was a pretty easy job. Probably even easier if you remove the vacuum things on the locks so you have more room to mount the motor.

Just re-read.... manual ac? Now you've got my attention. Please tell me you documented and photographed that?

I hate vacuum locks! (That's because I am having trouble with it right now.. All the doors will not lock or open when the engine is off) I want to know how to convert them!

It was a European car, it came with it I believe.

It also has a Ford engine. I don't think you'd want to do that too? :P

Not so much, I like the 617. Only exception being it's a touch low on power.

How about going with hydroboost brakes and switching to a manual transmission? :D

Vacuum leaks > Grounding/shorts


I'd MUCH rather replace a few vac connecters/lines/pods than have to troubleshoot an entire electrical system.

When I got my 500SEL the vacuum pump was missing from the trunk. The replacement I needed was unavailable (cost wise). The car has orthopedic (sp) seats which use the same pump. I ordered a door lock kit from JC Whitney which is designed for cars without power locks. I forget the cost but it was less than $100.00 for a 4 door car. The conversion was fairly easy as the actuators simply replaced the vacuum pods. I latter added keyless entry and every thing works great. I know this doesn't solve all your problems but it will make a good start.

So the JC Whitney item also fixed the orthopedic seat?

No, it didn't fix the seats. I only gave that information so you would know why the pump was so expensive. The orthopedic seats are just disconnected. When you buy a car for $500, you can't expect everything to work.

That's what I've done too, it gives you remote entry without hacking up the entire car. The vacuum system is really pretty simple if you just spend a little time fixing the little things when they fail. The cause of failure is almost always a connector of an actuator, they are both cheap and easy to fix. The only hard part is spending an hour finding the leak. If you don't want to deal with it, pay someone $100 to do it for you.

I live in North Texas. It's so hot and dry that corrosion rarely causes grounding problems. It does kill vacuum hoses, dashes, seats, paint, and weatherstrip regularly though.

The Audi 5000S used a bi-pressure pump mounted in the trunk.
The door switch reversed the polarity of the pump so it would pressurize to open the locks or vacumn to close the locks.

You could use that for you seats pmckechnie





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At least some models had the pump under the back seat, IIRC.

Going all electric and getting rid of vacuum in the Mercedes is quite an ordeal.

Here is a list of all the vacuum elements in your 300CD.

Lock system:
Drivers door control valve.
Passenger door element.
Seat back control elements.
Fuel filler door element
Trunk element
Vacuum reservoir
All lines and connections

AC elements:
Floor heat element
Defrost element
Fresh air element
recirculation element
Center vent elements
All your air valve control switches

Engine vacuum controls
Vacuum pump
Brake booster
Engine shutoff
Transmission shift control
EGR control
ALDA input

So to eliminate all the vacuum would require redesigning the AC control, engine control and transmission control????

Do you really want to take on those problems??

It is easiest in the long run to maintain the system as designed by Mercedes, And less frustrating.

To change your car to a manual AC system you need a manual donor car and all its parts. Then you still have to figure out how to attach the wire harness to the manual system.

Dave

IIRC the pre '82's where in the trunk but they got wet...later where under the rear seat on left side in a foam housing.




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Great list, thanks.
EGR? What's that? :brows:
The ALDA input is boost referenced.

I agree, chances are the conversion is not worthwhile. But you never know 'til you ask. For example, think if the a/c system could easily be converted to manual control, like a simple swap with a 240D. I bet about half of us, the half with persistant vacuum leaks, would have done it.

boycott?
 

as much of a PITA as it is to troubleshoot the vacuum system it is uniquely cool..
akin to the love of diesel power that we are drawn to in the first place.:D

I do have to admit that seeing the passenger lock sweeping closed gracefully is cool... much better than the electrics click!
Speaking of which, does everyone elses gas cap lid kinda thunk as it locks?

I got a a used pump from a fellow forum member for $40 shipped, including connector. It looks brand new, and works like new.

my w126 needed it.

Would not exactly call it easy. If you had a 240D and your "modern" car sitting next to each other, think about the job.

Remove both center consoles. Which means removing both drivers seats.
Remove both dashes
Recover the freon from both AC systems
Remove all controls, keeping track of all controls and their conections
Remove both evaporator boxes.
Replace the evaporator in the 240D box that is going into the "modern" car ( all that work and not replacing the evap would be foolish)
Installing the 240D evap box into the "modern" car
Install the 240D dash into the "modern" car ( center air vents and air temp sensor design difference, hopefully the same color)
Install the center console. Either the 240D console or put the 240D switch panels in the "modern" cars center console. AC switches are different
Figure out the wiring.
Replace the mono valve and tubing with the 240D heat control valve in the engine compartment.
Remove the water circulation pump to the ACC system.
Connect everything and make sure it works.
Charge the AC system and hope you don't have any leaks.
And after all of that the 240D still uses a vacuum element for recirculated air.

It is possible but after removing a 300TD AND a 240D evaporator box to replace the leaking evaporators, I find it easier to just keep the systems going as designed.
If you wonder what it looks like.

http://www.peachparts.com/Wikka/W123Evaporator

Dave

So the topic should change to "How can we help you with your vacuum leak problems???"

I would rather work on a vacuum problem than swaping a AC system.

I meant if it were an easy, simple job a lot of us would have done it. I was aiming more at the preference for simple, reliable parts than whether the swap itself was difficult or not. Any time you start talking about removing a dash I'll give you the Major PITA factor without question.

I wouldn't do it, I'd rather troubleshoot vacuum systems than electrical systems any-day. Once you get everything working correctly, it's pretty easy to fix individual problems as they come up.

I don't see how it would be all that difficult to swap the HVAC system from a 300D to a 240D. I have had the dash out of my 300D twice, once to replace the vacuum solenoids and the other time to replace the heater core. To do the heater core the whole HVAC box had to come out. Time consuming and tedious, yes. Difficult, not too bad. If I had a 240D sitting in the next garage bay to swap the parts directly over it would be pretty simple.

Granted this is pretty involved and you have to have the tools, space, parts car, time and ability to pull it off. Its a lot of effort but the result is a much simpler HVAC system and likely years of trouble free operation. I came very close to doing just this when I had to go in the second time to do the heater core. I just couldn't find a 240 donor fast enough. RT

Hi , please unerstand electric or vacuum the princeables are the same ! just remember its all about flow ! think about it, all you have to do is get a schematic and isolate the circuts !! whats the differance between a
vac-pod or a solinoid ? a diode or checkvalve ? wire or a hose !!to me its the same! For the amount of time to convert I could rebuild a 617 !my 2 cents !:confused: :confused:

Are you talking about the vacuum pump that sits in the spare wheel well? I have a working one from a diesel W126. Pm me if you want it ill let it go for cheap.

It's easy to see electrical leaks. Or feel them for that matter.

Like I said you got to get a vac gauge and break the circuits down to groups! it a hose, All it takes is a little common sence !

My w123 car is/was a 1980 European 230 - that was blown up by my neighbor’s daughter. I bought it for $500 at the age of 15. It does have a Ford power plant because a neighbor of my grandparents gave me that car free. So...

The w123 had two options...adjustable headlights, and a rear-heated window.
The Ford had a lot of options...one being power locks...so a little while with some aluminum, and a few bolts and wire cuts later - the car was equipped with power locks...albeit it the filler door...

The HVAC is manual...and I love it...both functionally, and aesthetically...

Power in my w123 is not a problem with the Ford power plant; the Eaton supercharger and the front mount air-to-air intercooler.

Jake