The dealership told me if you order a new injection pump, the VCV is included. That tells us that MB has the VCVs available; now how to put the squeeze on them to sell the VCV separately?

I did it this morning. That should be a sticky somewhere, maybe in the parts wanted forum? Or has it been made a sticky already, and I just missed it?

The rubber diaphragm is indeed the tricky part. I received the nitrile coated nylon, and it is not going to work. No flex. I realized that is what the bellows feature is for in the middle of the diaphragm, to allow movement without stretching. So, if there are any materials engineers out there, we need to figure out how to form these things. I believe you would need a die to squish it into, and then heat to just below melting temp, and then quench it or maybe just let it cool down. There are also various melting points for different recipes of nylon, and I haven't found one for nitrile, for which there are also various recipes, probably proprietary. So, the search continues....

Viton or silicon would have to stretch, not sure how long that would last before it tears. Viton could be glued in with RTV, and still taken apart, I think silicon requires some funky adhesive, never used it, don't know about disassembly.

As far as putting the squeeze on Mercedes, maybe we could organize a march and drive down to Atlanta HQ, the site of all those nice old cars lurching around the parking lot might embarrass them enough to start manufacturing the NLA parts. At least the ones that keep the car running.

Dealerships often know less about these cars than we do. As far as I know the pump for OM617 is NLA unless they still make them in India or they still have some NOS sitting around somewhere.

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'83 SD, 2x '85 SD
You are entitled to your own opinions, you are not entitled to your own facts.

I simply called a MB dealership parts department and asked them. They said the injection pump IS available albeit around $2700 (IIRC) and includes the VCV.

Considering the rust and other damage I've found in some of these pumps that might be not a bad price, way out of my budget sadly .

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-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

Sadly, MB is in reality out of almost everyone's budget including mine. That said, somehow those of us who have them continue to foot the bill to keep them going. We must like them a lot. Perhaps they are "the first wife"??

I agree a sticky would be very useful. MB have confirmed that use this tool and all unfulfilled Classic Centre enquiries to prioritize remanufacture of parts for each chassis.

On that note, you could email the Classic Centre asking to order all your known NLA parts for the W123. Eg. 1233500175 (rear subframe mounts). He will log your requests in their remanufacture queue if he can't fulfill them.

bernick.alvarez@mbusa.com

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Why I will never do business with "DieselKraut" again

http://www.peachparts.com/shopforum/mercedes-benz-used-parts-sale-wanted/378935-why-i-will-never-do-business-dieselkraut-again.html

Did you actually provide them with the OM617 pump part number: either A6170705001 or A6170704101? 2 MB dealerships I called indicated this pump as NLA as do all the parts websites.

Other engines have pumps that may still be available. The OM617 appears to be NLA.

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'83 SD, 2x '85 SD
You are entitled to your own opinions, you are not entitled to your own facts.

Thanks Nate for the description. I thought it would be easy to rig something to do this out of junk box parts but I got bogged down trying to understand my vacuum diagram. It gets confusing as it goes through the EGR stuff on the valve cover.

At some point I’m going to have to do something about this. I guess we all are. I was also thinking if there is a possible mechanical solution. But...that is basically what MB does.

Another crazy thought, is there something off a more recent vehicle’s vacuum control system (from the golden era of vacuum controlled vehicles) that converts throttle position to proportional valve movement? I suspect if there is something we can adapt it’s pressure profile using orifices.

I’m afraid to ask why the MB system is so mechanically complex. There must have been a reason for its design - probably the vacuum roll off profile as it goes from 15” to zero. I can think of 3d printing a gate valve with a lever that operates a gate but I bet it needs to be more clever than that given what the original VCV looks like.

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79 300TD “Old Smokey” AKA “The Mistake” (SOLD)
82 240D stick shift 335k miles (SOLD)
82 300SD 300k miles
85 300D Turbodiesel 170k miles

You are probably correct. I didn't provide a part number and the people who work the parts desk are not all that much up on vintage MB. If we don't get MB to start remanufacturing some of these parts, we are TOAST.

Just as a heads up, making parts , even really simple parts is insanely expensive, risky, and time consuming. Having done it a few times for the Mercedes community I can say it is not a task to be taken lightly. That VCV is a complicated piece of plastic and rubber designed to mechanically bleed off vacuum proportionately. Having done 3-D printing for incredibly simple items I can say this part to reverse engineer and correctly scan and figure out correct materials would cost well over $25,000 for the first one , maybe more. The second through the 1,000 one maybe $10 bucks each. Cannot even guess the price of milling each one. I would never take another risk trying to get another part to the hobbyist. Too much risk. Plus this forum is not really the best platform. I doubt you will see someone taking this risk unless there’s a known market to sell at least 3,000 at $50 each in the next 24 months

You're welcome .

Yes, from the late 1960's though the 1980's there were indeed vacuum control valves on a slew of American sedans, I no longer remember the speciaic brands but they did exist .

As mentioned, there's a lot of time involved in small batch aftermarket parts but, Mercedes could prolly have the original sub contractor make them cheaply enough .

Plastic molds are not terribly difficult to make .

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-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

Greazer - warning heard loud and clear. I’m just dreaming and running my mouth. At some point when I’m serious I’ll fetch a VCV at the JY. My 3d printer is too cheap to make a pneumatic part of automotive quality.

If all we need is a diaphragm maybe that’s where to start. Making a mold for two part urethane or silicone isn’t that hard. That is something a cheap 3d printer can do.

It’s tempting to head down to the JY and get one.

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79 300TD “Old Smokey” AKA “The Mistake” (SOLD)
82 240D stick shift 335k miles (SOLD)
82 300SD 300k miles
85 300D Turbodiesel 170k miles

Dkirk,

The smoke machine is really useful ha? I saw one demonstrated 5 years ago but did not want to spend $800 for one so built one myself.

Nice work! If the Silicone does not hold up, try Aquaseal https://www.westmarine.com/buy/gear-aid--aquaseal-neo-cement--19052455?cm_mmc=PS-_-Google-_-GSC%3ENonB%3EProduct%2520Type-_-19052455&product_id=19052455&creative=108421553044&device=c&matchtype=&network=g&gclid=CjwKCAjwnK36BRBVEiwAsMT8WP7ucBfkRjX2lvlAdUHok4v1H83QTokuOYjzUOuvyM04iiqIYa-IJBoCWjgQAvD_BwE

It is much tougher than Silicone. You may want to make a mould and inject the Aquaseal. I think it may have a good chance of working.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked