Subject says it all. In order to replace the diaphragm I need to get the top off the servo. In order to get the top off I need to depress the four clips on the lid. In order to get to the back two clips the servo has to come out of the car.

However the bottom of the servo has three plastic things that go into grommets into a bracket that seems to have no screws or other attachment points. So how do I get the servo out? Linkage is disconnected, but I think if I pry with a screwdriver I will break the three plastic things then what?

Can't find a procedure, stuck.

Thanks!
C

 

I think I used two small screwdrivers to release the tabs. Once one is released you have to hold it while you work on the next one or it pops back into place. Maybe with strong fishing line or floss you could loop around all the tabs and tighten the line like a tourniquet with the shaft of a screw driver?

You will have to bend the arm slightly to get the diaphragm out.

 

Well hm. Floss just breaks and I could not get in there with screwdrivers to pop the clips. Realizing that something else was going on I decided to just use Porsche tool P0999 (brute force).

Started by trying to remove the one way captive washers on the bottom. There are three of them and they bite into the plastic feet of the servo, putting pressure on them by slipping a screwdriver between the servo and the mount allowed me to get one off with a pair of jeweler's screwdrivers but wound up breaking the feet on the other two. Oh well, that's life in big city. At least the servo is out of the car.

Next step was to depress the tabs. Funny, I depressed a tab and it would not "set" (like picking a lock) when pressure was placed on another one. Something else was wrong. I tried using pliers to close two of them and fingers for the other two but nothing was moving. Great.

So I went to Porsche tool P0998 (Whatever you got). I tried the dental floss, that broke. Then I realized if I could slip some metal shims between the tab and the top it would keep the tab down and allow me to lift the top. But what do we have in the shop that is small, thin, very hard?


Why not.....

Yep, my spark plug gap feelers. I took four of them out, and slipped them around the tabs. Then once all four were set I angled them so they were 100% engaged. And....


Sort of works.....

Nothing.

Top would not come off. Oh THAT is great, it's on so tight it will not move. No wonder I couldn't get it off in the car.

So I used another screwdriver to put pressure against the tab holders and the bottom half of the servo to lift the top. Finally it came up and off but it is a very tight fit (which makes some sense as it's a vacuum seal).

Now the servo is open. And I can see the source of the leak, just a weak point in the rubber, the rubber looks fine otherwise.


Them's the breaks.....

And now I have to figure out where my $(*@(@ spare diaphragms are.

Hopefully this will help someone in the future. My guess is you can do this in the car if:

1) You shim each one of the tabs with a spark plug feeler gauge shim
2) You then use a screwdriver to gently break the seal between top and bottom.

For this, I'll just put the thing back in and let the spring pressure hold it. If it's sloppy I'll use some JB Weld and leave a note for the person in 20 years to have fun with it when it ruptures again.

My guess is Porsche's solution to this was to charge the person $15,000 to have the entire HVAC system pulled and replaced with a new unit as this is not very service-able in the car... Next up later will be the comb filter, then the defrost valve.

C

 

Final thoughts:

1. Make sure you line everything up and test fit the servo before replacing everything. The pins on the bottom are not at 120 degree angles, thus there is only one combination of top, bottom, and linkage orientation that works.
2. Get the linkage set up and marked before putting it all together: With the top on, turning the linkage can twist the bladder inside with the usual eventual ripp-age.
3. When done enjoy the fact that your bottom heater flaps will now work, however since the default with a blown servo is "flaps closed" it will not increase the AC volume (which is blowing out the defroster vents due to that servo failing in an open manner). Oh well.

With my feeler gauges, swapping out the comb filter bladder should be a snap. Just need to pull the console, and the glove box, and the passenger tray and the....... :-)

 

Mine did not give me this much of a fight but I had the whole front half of the HVAC box out of the car so it was easier to work on. Nice trick with the feeler gauges!