awilli6

Will a leak in the defrost flap actuator affect the cooling on an 87S4? I replaced the footwell actuator already & now it holds vacuum. Are the diaphragms the same size?

awilli6

Any responses on this? Are the footwell & defrost diaphragms the same size? Is there a picture of the defrost actuator available.

Mrmerlin

the defrost actuator is on the left hand side of the HVAC box you have to remove the pod for access.
Note it doesnt usually go bad as it doesnt get used,

Note the defrost pod is the same size as the 2 pods in the center of the console, These 2 center pods do fail however.

The footwell pod on the bottom of the blower box is a bigger size.

any leaks in the pods will cause the whole system to run low on vacuum when any of the leaking pods are actuated.
Otherwise the solenoid rail will vent all of the pods to atmosphere when the pods are not being actuated

lonnie77

http://www.flickr.com/photos/lonnie7...57623788139925
It's the red and black thing to the right. If you replace it remove the bracket on the new one and use the old bracket. The lever arm should come off with a little help of a screwdriver.

awilli6

Can I just replace the rubber diaphragm in the defrost actuator?

dprantl

Yes, you can.

Dan
'91 928GT S/C 475hp/460lb.ft

WICruiser

Talk to Roger at 928sRus. He can sort out what you need.

ROG100

I have never found a diaphragm for the defrost actuator but at only $46 for the complete actuator it is not such an issue unlike the highly priced center and footwell actuators.

dprantl

You can buy the whole actuator and then just replace the diaphragm without removing/replacing the whole thing.

Dan
'91 928GT S/C 475hp/460lb.ft

awilli6

Thanks guys. Got the actuator ordered today & some very good advice from Roger.

SMTCapeCod

Sharing the advice would be good/appreciated.

Anyone else? I have other work requiring pod removal, and have the complete actuator on hand, but not having much success finding stepwise R&R and gotchas, aside from ammonman's replacement of the membrane with pod in place. I'd prefer to do the whole thing, depending on degree of engineering and fantabulous specialized tools required.

syoo8

Steve, as I wrote you in a PM, when I did this job (three years ago) I thought I would be "cute" and disassembled the pink HVAC actuator and replaced the rubber membrane only.

BIG MISTAKE.

The old HVAC actuator with the new rubber membrane failed to hold vacuum, it was a bloody mess, and I had to call Roger to get a new one.

The tricky part of the job is to get the HVAC defrost actuator separated from the metal mounting bracket... It has been a few years but I remember separating the two with a flathead screwdriver, some elbow grease, and patience.

SMTCapeCod

HVAC- Scott that helps, thanks!
I thought I recalled a thread with someone griding off a rivet on one of the actuators and trying to replace with a bolt/screw and having a difficult time...must've been one of the units under the console where the membranes are typically replaced now.
So, I'm pleased to know it is a matter of angle, articulation and access rather than drill, dremel and disgust.
;-)

On the other hand, now I think I need to change my avatar~
I must've channeled your spotless shot subliminally when taking/picking my image!
Which wireset is that you have?

SeanR

I usually can replace the defrost actuator with out removing the pod. Granted, getting the new actuator in and the cap on so it seals can be a trial, but it's not necessary to remove the pod. You can access the top of the cap with the pod in the upper most position and the lower while hanging out upside down under it.

Take the vacuum line off, pop the cap out of the way, disconnect the arm on the defrost assembly and pull it out. Be gentle putting the new one in and pay particular attention to the diaphragm rubber ring, if it's not all the way around the cap do not force the cap on. Doing so may destroy the diaphragm.

SMTCapeCod

OK, so I got in there and was confronted with the riveted on bracket. I chose to work on the one-way press fit washers that secure the module and remove the pod from the bracket as others suggested. Biggest PITA for me was getting the actuator attached to the "arm" again Not my favorite job. And, to top it off, I rechecked for vac prior to removal, saw some slight loss....but then when I had the old pod out it held vacuum fine. Perhaps leaking from the manifold or back through the footwell or recirc. blah.