Hi,

This is the second time in a couple of years I've had to mix and match parts to make a Frankenstein vacuum actuator so I thought I'd post it up. The selection of vacuum flap actuators is getting worse and worse by the month. Not to complain, MB has been a hero supporting up to 40 year old cars, but it is what it is. NLA. I tried to find the defrost flap actuator on my 85 300D and it is NLA. PN: 1238003275.

To get it out I used dmorrisson's post* on changing pods without removing the dash. His tricks work and are definitely easier than removing the dash, but they always result in broken up lock tabs and plastic mount pins. I needed a new part. Gluing, rebuilding, etc. was not an option.





I dug around and was able to find this part on the Pelican website. 0008005775



They are pretty close to each other. They're both double acting pistons and they both have the black twist lock bayonet mount as opposed to the little pins and push washers. So I drilled out the rivet on the old one and it just snaps into the new one using this little snap lock bracket on the new style. The modern ones eliminated the rivet. I had to reclock the black portion with respect to the pink portion so the vacuum nipples ended up in a friendly orientation.

You basically push down the little clips one at a time and separate the shells, rotate, then put it back together.

Just thought this might help you guys with the never ending all too often issue of NLA. Its getting worse. I got into these cars because they were inexpensive and high quality and easy to fix. The parts availability is becoming a bigger and bigger issue. These diaphragms cannot be realistically bought used and still be expected to hold up. It just isn't worth all the work of installing it. There's a huge community of hoarders/gougers** gathering up all the junkyard parts but that won't cut it on these diaphragm actuators.

My naive observation is there seems to be only two types of pink actuators. Single and double diaphragm. The difference is bayonet mount or push washer mount and the metal tang or hook thingie on the end. I think we can just do this with any pod as long as we save our metal portion or make one.

Finished actuator - 1238003275 equivalent. New pod + old metal tang. I can keep driving a little longer.



*this post is a great one. Worth reading.

W123. My experience with replacing all AC vacuum elements without removing the dash.

**I am going to withhold my rant here. You guys are good and bad. I’m happy you’re rescuing parts from the junkyards but the prices you are charging are insane. This is America and I toast your capitalistic efforts.

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

Try these guys for the diaphragms. Click the "Climate Control" tab for selection of ACC version.

Performance Analysis | Climate Control | Diaphragms | Blower Motors | Pushbutton Panels | Vacuum Door Locks | Autotemp | Cruise Control | Engine Oil Analysis | Mercedes-Benz Parts | Mercedes-Benz Club of America | Oak Ridge | Car Care - Home | Perfor

__________________
“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now

Oh nice! Unfortunately I cracked mine up getting it out. For the defrost flap unit there isn’t much space to get it out and I had to break he tabs to free it. Actually I didn’t know how the release tab worked till I got it out on the bench. So it was destroyed. At that point I was just happy I could get it out.

I think if I had to do it again I could release it without cracking the tabs.

I’ve replaced the main flap, center flap and now the defrost flap actuator. The leg and recirculated air flaps have slow leaks but my vacuum pump can keep up for now. Eventually I’ll pull those.

My AC blows better now. The defrost vents shut off all the way now. I don’t think they did before. The whole reason I started this is under certain AC operations my locks would malfunction and I traced it to the HVAC. The defrost flap is somehow mounted in series with the center vent and it shows up as a leak on valve 1 & 3.

Anyhow it’s working pretty well. At some point I’ll look into repairing the last two pods. They’re both single action so I probably can get some single diaphragm units and swap out the linkage rods.

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

Thanks for the help! I bought my diaphragms from performance analysis. Have not installed yet but they were quick to send order and communicate with me. Plan is to replace all the diaphragms. They have some mods to make the pods last longer too.

Would be nice to compile DIY resources for rebuilding the HVAC systems. Things like materials for the foam and seals, sealants, glues, things to check while tearing everything apart.

__________________
Theseus

Instragram: doss_project
1984 300SD - 930 Blue, OM 617
Murfreesboro, TN

Theseus owned a ship in Greek mythology, and when a part of the ship needed replacing, it was replaced. Eventually, everything was replaced. Is it the same ship? (I own the car of Theseus. )