The last weeks brought some serious 928 wrenching fun. Because of slow vacuum leaks in the climate control that caused the recirculation flap to flip flop depending on engine speed, I decided to replace the old rubber manifold at the solenoids in the console, along with the ajoining connector pieces. Well, that fixed one slow leak, but when testing everything I found two slow leaks in the vacuum actuators further down the lines...

So I decided to take the console out all the way and bite the bullet - replace the center vent and footwell vent actuators. I searched rennlist and read Ed Scherer's clever procedure for the airbag cars that saved me from having to removed my dash...

So, I got the parts and decided to to the footwell actuator first. Since it's sitting outside I thought I'd just replace the whole unit. But in typical 928 fashion that wasn't possible without further major disassembly (the bracket appears to be screwed on from inside the heater box). So I opened up the existing actuator and replaced the rubber diaphragm with its little arm.

Similar approach for the center vent comb flap. But first I had to drill a hole in the heater box <crinch>. Once that was done and the pain of destroying a perfect heater box eased, it was real easy to replace. I used a 1" plastic piece from the hardware store to close up the hole. They had no matching rubber piece, which I would have preferred.

I buttoned things up and did my vacuum testing before starting the reassembly of the center console - which took forever due to a parallel interior remodeling project. Nice thing is that I was able to realign the console better with the dash than before. Now everything is straight as can be, and my footwell flap is no longer flip-flopping around...

Most puzzling to me, however, are the old diaphragms - they are nice and soft, without any visible cracking. I can't see where these would leak. Only thing I can imagine is that in one actuator, there was a hint of debris - maybe that didn't allow it to create a proper sealing surface. Really strange... I'll keep these for reference. The new diaphragms were brick red, BTW.

 

Stretch the diaphrgam with your fingers and you will find small splits. Some are very small.
I have the replacements for the large fresh air actuator.

 

Just like ROG says, you need to stretch it out a bit.

 

Nicole
Did you replace the recirculation actuator? I need to do mine soon...?

 

No, the recirculation actuator as well as the defroster vent actuator are air tight on my car.

 

Nicole,

So you like taking the dash off? I would have replaced as much as reasonable/necessary to prevent a second entry.

Cheers,

 

No, the dash wasn't out. From what I understand you don't need to take the dash out for the other two actuators. One requires pod removal, the other one is accessed from the engine compartment side after removing a bunch of stuff...

 

You've inspired me to tackle mine. Thank you.

 

Boy oh boy, how timely. Yesterday, I took out the console (airbag car) to chase known vacuum climate leak and to get to the manifold for a thorough check. It had been done before, probably by a dealer for warranty work. Found a pile of the small black screws that retain the climate controller and warning module stuck to the sound insulation. The hardest part turned out to be one of the bolts holding the console at the top in the air vent. PO (dealer?) had glued some plastic made-up spacers to the dash, and one of the bolts would NOT let loose because it was spinning that plastic washer/spacer thingy. Was going to Dremel my way to success, but not enough room. Had to use very long angled needle nose pliars to grab that plastic bit and slowly turn the bolt. Thanks to this forum, I knew about the bastard 8mm screw on the passenger side hiding beside the air bag. Thankfully, it was loose, and with only a coupla turns with a box wrench, I was able to get one finger up there to twist it all the way out. I'm impressed whoever actually did the prior work got it back up there.

Turns out the center vent servo has a tear. I'm going to take one more run at removing the plastic air duct between dash and air back, but expecting to do the hole-drill-and-plug procedure.

Question for Nicole: I'm assuming you got a new pod and just swapped out the guts, or did you get one of those AutoluxMBZ parts to work?

 

Rog, how are those replacement diaphragms coming?

 

As I already mentioned I have the replacement diaphragms for the actuator above the blower, fresh Air/Inside Air Flap (usually the Blue Line on the 928).
The others are progressing well with tooling already ordered.
I have had each diaphragm drawn up and tooling designed. I am paying 100% for the full ownership of the tooling. The next step is to review samples in different materials as the technology has moved on significantly. We should be able to use a material with wear characteristics that outlive us.
As soon as I know you will.
PM me if anyone needs the fresh air diaphragm.

 

JP Rodkey: I had ordered two complete actuators - one for the comb flap, and one for the footwell flap. I used only the guts of these new ones, after cleaning out the old housings. It seems impossible to replace these housings without access from inside the heater box.

 

Thanks.......that's pretty much what I thought. Will order the center pot. I was able to see into the box and get the old arm where it connects to the flap. It might be possible to get something in there to snap them together without drilling the hole - at least worth a try.

 

Perhaps some kind of flexible long armed grabber, sort of thing used in endoscopic surgery.

 

I have a surgical clamp, that that won't work - hole is too small. I'm going to try a long flat blade screwdriver (with small shaft) to try to weasel it onto the connector. It will be a surprise if it works, and I expect to do the hole-saw dance - but certainly worth a try. Will post results back on this thread after I get the actuator.