[Austria_Hungry]

Since I pulled out my center console I decided I'd investigate my lack of footwell air. I got a MighyVac and disconnected the elbows on the solenoid switch and pulled a vacuum. Stations 7,6,5, and 4 held a vacuum (and I could hear the pods actuate for some - some pods would actuate just once). Station 3 didn't hold a vacuum. I pulled the pod out and tested it, and that held true. Stations 1 and 2 did not hold a vacuum. I pulled both of the recirculation vacuum pods and tested them outside the car. Both held a vacuum and actuated.

My logic is that my rubber elbows and tubing are bad, but perhaps I am doing the testing wrong for the recirculation pods. Both these pods seem to be interconnected. The vacuum line that powers the short-stroke pod also goes to the long-stroke pod. Is there a different way of testing these pods through the solenoid? Could my solenoid be bad? Any great difficulty in replacing the vacuum tubing? Also, since these pods are out I might as well get new ones. How difficult was it to switch the long bronze arm over to a different pod? Does anyone know the part number for the 3-way rubber connector? Does anyone know the part numbers for the vacuum tubing?

 

[Austria_Hungry]

I tested just the piping by plugging the exit at the 3-way connector and the exit at the elbow. The line held a vacuum. I believe the part number for those 3-way connections is 201-805-01-22. Mercedes calls it a distributor. I am a little confused, why is there a vacuum in every instance except when the pods are attached?

 

[isthenew]

The tree of seven can go bad. Some of the pods are NLA. I bought the diaphragms and rebuilt all of mine. The vacuum line can be purchased at places like NAPA. However, it will no longer be color coded to the tree of seven. I believe the color coded lines are NLA, but I could be wrong.

I'm having basically the same problem. I replaced all my connections a couple weeks ago, and I'm still blowing air up through the defogger. I plan to test each line again today.

That three way splitter, I ordered them based on the part number I came across. What I received is what is in your picture. However, they are HUGE! At least 3 times the size of my old splitter. The new ones seem to be equilateral, where as the old one looked directional. With an in and two out on the other side. Because of the size, the new ones were tight upon install.

 

[MBL87560SEC]

I tested just the piping by plugging the exit at the 3-way connector and the exit at the elbow. The line held a vacuum. I believe the part number for those 3-way connections is 201-805-01-22.

Since I pulled out my center console I decided I'd investigate my lack of footwell air. I got a MighyVac and disconnected the elbows on the solenoid switch and pulled a vacuum. Stations 7,6,5, and 4 held a vacuum (and I could hear the pods actuate for some - some pods would actuate just once). Station 3 didn't hold a vacuum. I pulled the pod out and tested it, and that held true. Stations 1 and 2 did not hold a vacuum. I pulled both of the recirculation vacuum pods and tested them outside the car. Both held a vacuum and actuated.

My logic is that my rubber elbows and tubing are bad, but perhaps I am doing the testing wrong for the recirculation pods. Both these pods seem to be interconnected. The vacuum line that powers the short-stroke pod also goes to the long-stroke pod. Is there a different way of testing these pods through the solenoid? Could my solenoid be bad? Any great difficulty in replacing the vacuum tubing? Also, since these pods are out I might as well get new ones. How difficult was it to switch the long bronze arm over to a different pod? Does anyone know the part number for the 3-way rubber connector? Does anyone know the part numbers for the vacuum tubing?

201-805-01-22 I don't think that's the three-way you seek.

See part 38 in this image below.
Also for the vacuum tubing reference, see 32 of course.

Here's a reference for the pods.. As has been mentioned, several are NLA at this point.... I think it will be fairly 'easy' to swap actuator linkage from one to another, at least in theory.. :/ I have purchased several with that idea in mind as I have found the recirc/fresh air ones have been the first to fail on my early gen 2 SEC.
Initially, [and many years ago], I rebuilt them using replacement kit from Performance Analysis. This proved unsuccessful really, so I ended up replacing them with new the next driving season.
I find the double diaphragm pods overall to be first to go/ be needing attention.

As you can see in these pod linkage images the metal rod/arm is assembled over an indexing pin in the white plastic 'footer' and then a built in tab clips the metal part in place.
One may need to rotate the top vacuum chamber in relation to the bottom one to emulate the original vacuum port configuration when modifying.

MBL

 

[ProgMuscle]

Just a WAG... Have you done a smoke test of these vacuum lines?

 

[isthenew]

I tested each of my lines today, and made a couple changes. One thing I did was swap out one of my pods at the air flap for an extra one I had for another location. It has a different part number. But if memory serves, all the rebuild diaphragms were the same for the dual action pods. So swapped the metal connectors, and put it in.

In the picture below, reading left is the replacement pod, with the needed metal connector on it. Its original metal connector is next to it. And my original pod at the flap, with its original connector, are on the right.

After my changes, my vacuum system still seems to be not changing flow, even though every line (and connector) pulls and holds vacuum. Tomorrow I'll plug all the outlets on the Tree of Seven, add the pods individually, and see if I can track the problem further.

 

[MBL87560SEC]

I tested each of my lines today, and made a couple changes. One thing I did was swap out one of my pods at the air flap for an extra one I had for another location. It has a different part number. But if memory serves, all the rebuild diaphragms were the same for the dual action pods. So swapped the metal connectors, and put it in.

In the picture below, reading left is the replacement pod, with the needed metal connector on it. Its original metal connector is next to it. And my original pod at the flap, with its original connector, are on the right.
View attachment 2811725
After my changes, my vacuum system still seems to be not changing flow, even though every line (and connector) pulls and holds vacuum. Tomorrow I'll plug all the outlets on the Tree of Seven, add the pods individually, and see if I can track the problem further.

Hi there,

Noting the 5775 & 5875 of the part numbers there I see these pictured are the Fresh/Recirc pods, as you said above...

If so, here's perhaps a related story from my 126 archives:
Way back in the day, I rebuilt those two on my 560 as they would not hold vacuum. [Each had a ripped diaphragm.]
I installed diaphragms sourced from a well known & respected Mercedes enthusiast.

Though a PITA at times, the rebuild went well, both pods now held vacuum and seemed to work OK.. They were reinstalled, etc. The system was checked for vacuum integrity and all was good, right?.
On the way home I immediately noticed the recirculate function was partial at best. I could still smell the diesel fumes from a gravel truck ahead in traffic.
I'm here to say I never got satisfactory recirc action with the rebuilt dual diaphragm pods.. ever. Apparently they just could not exert as much pull as original ones in good shape.
My rebuilt single diaphragm pods worked just fine.

****
"#22 · Oct 16, 2016

I'm with Dan & Mike on this too…

Over a year ago, I rebuilt my recirc/fresh air flap actuators with the diaphragm kit mentioned earlier… It NEVER worked properly after that and was a step backward in my opinion.

Wrestling with the old & brittle actuators was NOT fun and coupled with additional R&R to make it right using brand new…. Uff..

Early this season I replaced the pods with new from MB and problem solved.

Just 2 cents

MBL "
****
As above, these rebuilds were replaced with new pods during the next driving season with good results generated.
I have had zero ACC air distribution problems since that time.

M

 

[compu_85]

On my car I found the vacuum solenoid stack had developed leaks. I first added some glue to it, which lessened the leak, and eventually replaced it.

-J

 

[isthenew]

I got my system working today. The first thing I did was take some extra hard vacuum tubing and sealed one end. This allowed me to plug any and all of the connectors. I found leaks on the 2 lines to the recirculation flap vacuum pods, and at the defogger vacuum pod.

Going through things systematically, I had a couple insights. First, while we all say the system defaults to blowing up at the windshield (defog) when there is a vacuum leak, that is the first line I connected and got working. And, even with other lines unplugged and open on the tree of seven, the defog vacuum pod still held vacuum, so I did not have air blowing up onto the windshield.

With regard to the defogger vacuum pod, what I did find is the white plastic lever needs to be almost all the way up to block airflow to the windshield. In my car now, the vacuum pod was activating, but not enough to pull the lever all the way up. The vacuum pod in there was one I rebuilt. And I checked a couple other dual vacuum pods I rebuilt. None of them have enough pull to lift that white lever enough to block the upward air. I installed an original one I had and it does fully close the flap.

Also, I found on the recirculation flap's vacuum pods that I could not find/stop a leak from the first pod (left) to the second (right). What I did find is the first pod is capable of opening the flap by itself. So I simply removed the second flap.

I'm of the opinion that the single vacuum pods are all the same. And the dual vacuum pods are all the same. With the different part numbers being for the metal connecting rods. At some point I'll buy a bunch of new ones and swap them out.

 

[Austria_Hungry]

I realized that the recirculation pods can hold a vacuum in two different chambers (thus double diaphragm...). The diaphragm controlled by the bottom tube worked fine, but the diaphragm controlled by the upper tube (one closest to the bronze arm) would not hold a vacuum. I pulled out my defrost pod and it held a vacuum on both tubes (thus why it didn't fail when I tested it at the tree). Kind of silly on my part but I'm glad I figured it out.

When I tried to order two of the short-arm recirculation pods my local dealer told me they were on backorder with no ETA. I ordered the last 2 that were in stock from PelicanParts. Looking at my pods it seems like the arms are interchangeable between the recirculation pods and the defrost pods. I think anyone could make their own arms and plastic clips and attach them to any double diaphragm pod to recreate the recirculation pods when they go out of stock.

 

[MBL87560SEC]

With regard to the defogger vacuum pod, what I did find is the white plastic lever needs to be almost all the way up to block airflow to the windshield. In my car now, the vacuum pod was activating, but not enough to pull the lever all the way up. The vacuum pod in there was one I rebuilt. And I checked a couple other dual vacuum pods I rebuilt. None of them have enough pull to lift that white lever enough to block the upward air. I installed an original one I had and it does fully close the flap.


I'm of the opinion that the single vacuum pods are all the same. And the dual vacuum pods are all the same. With the different part numbers being for the metal connecting rods. At some point I'll buy a bunch of new ones and swap them out.

I am sure your vacuum pods assessment is spot on there... in round numbers, the linkages are the differing factors....


I found exactly the same as you in regards to the rebuilt pods.. they just did not have enough travel from 'at rest' to 'full actuation'.

M

 

[MBL87560SEC]

Looking at my pods it seems like the arms are interchangeable between the recirculation pods and the defrost pods. I think anyone could make their own arms and plastic clips and attach them to any double diaphragm pod to recreate the recirculation pods when they go out of stock.

I think it might be even easier than fabbing up new actuating linkage. Those metal links just clip onto the business end of the pods. My way of thinking is if it clipped together, unclipping seems a natural progression, you know?



For that endgame, I bought 2 of the same fresh/recirc pods intending to repurpose one for NLA duty later on.

 

[isthenew]

Yeah, the metal connectors unclip and are interchangeable with other pods. As you can see in my picture. The the reading left pod, the original clip is underneath. And a swapped clip is on the left pod. Maybe it's difficult to see as the plastic is black on both of those clips.

 

[Austria_Hungry]

Part 201-805-01-22 arrived and it's exactly like what I pulled out of my car. It works very well as a 3-way connector and is snug with the pod and the tubes. I ordered 2 of the short-stroke pods and changed out one of them with my old long bronze arm. Apparently, they are not exact copies of each other, but rather mirrors. When I twisted the pod into its mount little nubs were not pointed the right way. I will need to add some extra tubing

 

[MBL87560SEC]

I have considered rotating the pink 90 degrees in relationship to the black base to match...

Additional hose is probably an easier approach though..

M

 

[Austria_Hungry]

Here is the extra tubing to make it work.

 

[isthenew]

Ohhhhhhh, I like that. I ordered a couple of those splitters and some extra hard vacuum line a couple weeks back so I could add back in that right side pod (which I currently have removed). I think I'm going to do this.

 

[Austria_Hungry]

Ohhhhhhh, I like that. I ordered a couple of those splitters and some extra hard vacuum line a couple weeks back so I could add back in that right side pod (which I currently have removed). I think I'm going to do this.

I cut the white hard tubing to 6.5 inches. 7 inches will give you more to work with but I was worried it would take up a lot of space. It is a tight fit.

 

[MBL87560SEC]

Here is the extra tubing to make it work.

Nicely done!