87 300D center vent pod replacement - Page 2 - PeachParts Mercedes-Benz Forum

Bio300TDTdriver · #16 03-01-2009, 06:53 PM

Yes I remember those screws well. I had to borrow my wife's makeup with the mirror. I didn't have one of those nifty ones you have. That was not one of MB's better designs.

gsxr · #17 03-01-2009, 09:16 PM

Quote:

Originally Posted by Bio300TDTdriver

Yes I remember those screws well. I had to borrow my wife's makeup with the mirror. I didn't have one of those nifty ones you have. That was not one of MB's better designs.

Sadly, this is one of those items MB didn't intend to be serviced in the car.... I think they expect you to pull the entire heater box out and work on it out of the car (yes, we all know how impractical this is). Out of the car, it would be a breeze.

On a side note, for the nearly-invisible screws that need a mirror to remove, magnetize your screwdriver tip before starting this. That way the screw should stay attached and has less probability of falling in the nether regions of the car.

Oh, and you can buy the little C-clips separately, in case you lose one. EPC group 83, subgroup 045, callout 77 (for the 1987 300D anyway). P/N 201-835-01-34. One dollar each MSRP.

BTW - awesome photos, Sixto!!

Jeremy5848 · #18 03-01-2009, 11:16 PM

Yes, especially the pix of getting the screws out from the "back" of the airbox cover. Hard enough to get the mirror and screwdriver in there without having to operate a camera at the same time. Good job. C'mon up, you can do mine next!

bondtwin1 · #19 11-03-2009, 08:50 AM

Is this why I am not getting air coming out of the center vents. I noticed this more since I turned on the heat. How can I tell if all the switches are working. Is there something else I can try first. I have a 1987 300D turbo and I don't know how to remove the dash.
Thanks
bondtwin1

Bio300TDTdriver · #20 11-03-2009, 11:13 AM

The system was not designed to provide heat out the center vents. When it is set on heat you will get heat from the two side vents and the floor.

Jeremy5848 · #21 11-03-2009, 11:23 AM

You can "rewire" the vacuum plumbing so that the center vents are open all the time. It's really nice to have heat for your right hand as well as your left. All you have to do is to remove the glove box so you can get at the vacuum manifold, then remove the center pod line from the manifold (I forget the number -- it's in one of Sixto's threads) and tee it into the main vacuum line. The center pod then gets vacuum any time the engine is running and is thus open at all times.

gsxr · #22 11-04-2009, 10:09 AM

Quote:

Originally Posted by Jeremy5848

You can "rewire" the vacuum plumbing so that the center vents are open all the time. It's really nice to have heat for your right hand as well as your left. All you have to do is to remove the glove box so you can get at the vacuum manifold, then remove the center pod line from the manifold (I forget the number -- it's in one of Sixto's threads) and tee it into the main vacuum line. The center pod then gets vacuum any time the engine is running and is thus open at all times.

You can do this, but it only works if the center vent pod is good, and on most 1980's-vintage models it's usually dead. You have to test all of 'em with a Mity-Vac, as mentioned in the first post on this thread.

On a side note, my 1987 300D project car (to be for sale soon) had ALL the pods dead. Every single one was bad and would not hold vacuum. I had to replace all the buggers! The system works fine now...

Jeremy5848 · #23 11-04-2009, 10:30 AM

Quote:

Originally Posted by gsxr

You can do this, but it only works if the center vent pod is good, and on most 1980's-vintage models it's usually dead. You have to test all of 'em with a Mity-Vac, as mentioned in the first post on this thread.

On a side note, my 1987 300D project car (to be for sale soon) had ALL the pods dead. Every single one was bad and would not hold vacuum. I had to replace all the buggers! The system works fine now...

Indeed. The center vent pod (and most of the others) on my '87 300D (W124, OM603) were either dead or leaking (pinhole in the rubber) so that they worked poorly. The double-lift pods in particular were either half or all the way dead. In the 123 climate control system it's possible to jam the center vent open but that is more difficult in the 124. When I replaced the dash in the 124 I took the opportunity to replace all of the pods. I have to do the same later this month for the 123 when I replace its dash.

Jeremy

Keoki · #24 07-26-2011, 01:25 AM

I have a 1987 300E 3.0L which only blows air from the defroster vent on the dash and the side vents. Both the high and low fan speeds work. The center vent, the two footwell vents and the rear floor vents do not work.

When I press each climate control unit button it produces a clicking sound in the vacuum control valve, but no change in air flow from the the center and footwell vents.

I followed Jeremy's instructions to removing the radio and the center console to expose the various wiring harnesses. the two footwell vacuum pods, and the various vacuum lines. I tested the vacuum control valve (Y7 Switch-over unit) by putting 12 volts across the seven pins and the common pin. I found that each pin made a "click" sound when tested. Should I conclude the vacuum control valve is ok?

When I disconnect each vacuum line from the vacuum control valve I feel NO evidence of a vacuum in the line. I don't know if I should feel a vacuum from the line, but I wonder how the vacuum is generated in the first place. Also, I see from the manifold and from the photos that each nipple has what looks like a brass metal piece in the nipple. I presume that might be a piston for the solenoid, but this is just a guess.

Then I found your you article here. Many, many thanks for the accurate photos and clear instructions. Now I wonder if my problem might be a faulty center vent pod among others.

Is there a way of testing if the problem is the center vent pod short of removing the dash? And then there is the problem of no air coming from the footwell vents.

Many thanks in advance for any advice you can provide.

gsxr · #25 07-26-2011, 09:47 AM

Quote:

Originally Posted by Keoki

Is there a way of testing if the problem is the center vent pod short of removing the dash? And then there is the problem of no air coming from the footwell vents.

Yes - you have to test each of the 7 vac lines to the pods with a Mity-Vac, as described earlier in this thread. That is the definitive test to determine if a pod is good or bad. Since your car is a 1987, I would bet that you have several failed pods, and if you pull the dash it would be foolish to not replace ALL of them.

BTW - vacuum is supplied by the engine, and the engine must be running (idling) to get any vacuum, with either gas or diesel engines.

Jeremy5848 · #26 07-26-2011, 10:48 AM

X2 - highly likely you have several bad pods. Remove each hose from the valve assembly and pull a vacuum on it. Those that will not hold a vacuum are bad. Pulling the dash is time-consuming but not really a bad DIY job. There are several good threads in this forum on that subject. Best to replace all the pods, as GSXR says.

Aquaticedge · #27 07-26-2011, 12:07 PM

x3. It's what I just did. Job sucked (no pun) and took a little while. but after it was done. I have air going where it should be.

1stbenznc · #28 07-26-2011, 08:51 PM

Just finished doing all my pods yesterday (except the rectangular one - bought two round ones instead). What a job! - Not hard, just a bit time consuming!

All five of my pods would not hold vacuum and were broken. Typical no air from center vents. I got lucky and the rectagular one was still working.....and accessable later without pulling the dash

Cool air can actually reach the kids in the back now

Thanks for all these write-ups; from pulling the dash to how to replace these suckers.

It's pretty nice to hit the buttons and they do what they're suposed to.

Keoki · #29 07-27-2011, 08:15 PM

I am grateful for your advice and instructions which I will faithfully follow. I'll let you all know how it turns out. Again, thank you very much.