Fixing HVAC leaks
04-10-2007, 07:53 PM
#1
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Fixing HVAC leaks
I have just finished fixing my HVAC actuator system in the dash.
Found two leaking vacuum clocks, Center Comb and Footwell flap.
Took them apart in the car and saw two small holes next to each other in the rubber membrane on the first one.
Since I have been repairing flat tires three times the last week on my sons bike i thought why not, let's fix them the same way.
Not sure how long this will hold up but it is wort giving it a try considering the cost of these babies.
Tested to pump vacuum and they now hold it perfect and the actuators move like they should.
Have anyone else tried this quick and dirty fix for this rather common problem?
Cheers/Peter
Found two leaking vacuum clocks, Center Comb and Footwell flap.
Took them apart in the car and saw two small holes next to each other in the rubber membrane on the first one.
Since I have been repairing flat tires three times the last week on my sons bike i thought why not, let's fix them the same way.
Not sure how long this will hold up but it is wort giving it a try considering the cost of these babies.
Tested to pump vacuum and they now hold it perfect and the actuators move like they should.
Have anyone else tried this quick and dirty fix for this rather common problem?
Cheers/Peter
04-12-2007, 03:43 AM
#3
Drifting
Not tried the HVAC actuators (bought new from Roger Tyson instead), but did this over two years ago with the track control arm.
I'll attach a pic later when I can work out why I'm not allowed to anymore...
04-12-2007, 05:22 AM
#4
Drifting
That's very interesting Peter. I had exactly same leaks as you (footwell, centre comb) and got round to doing them last week but I had already bought the footwell actuator (decided just to seal off the centre comb line for now as not very important).
Found two tiny tears in the footwell 'bladder' which of course expand as the bladder expands when vacuum applied to it. I just replaced the bladder and I think the arm (you could just replace the bladder which makes the cost even sillier!) but I thought a day or two later when my wife's bike had a puncture whether a puncture repair would do the trick. Can't see why not so please report back after a few weeks use whether still ok and I will try repair the center comb that way (nothing to lose except time fiddling with the actuator arm in the heater box!)
Found two tiny tears in the footwell 'bladder' which of course expand as the bladder expands when vacuum applied to it. I just replaced the bladder and I think the arm (you could just replace the bladder which makes the cost even sillier!) but I thought a day or two later when my wife's bike had a puncture whether a puncture repair would do the trick. Can't see why not so please report back after a few weeks use whether still ok and I will try repair the center comb that way (nothing to lose except time fiddling with the actuator arm in the heater box!)
04-12-2007, 06:43 AM
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The center comb actuator is the most difficult to replace and also the most expensive of the actuators.
I repaired mine in the car, just removing the cap and spring, it is a bit tight but can be done relatively easy.
Since it is vacuum the repair on the outside will see no pressure just the vacuum.
On my car it was the side facing down on the rubber lip that had holes, just on the edge to the plastic cup/piston it sits over.
I pumped vacuum up to 300 mm Hg on the meeter, after half an hour it was 250 and after one full hour 200.(at slightly above 200 the center comb flap started to close again.
I will keep you posted on how it works
/Peter
I repaired mine in the car, just removing the cap and spring, it is a bit tight but can be done relatively easy.
Since it is vacuum the repair on the outside will see no pressure just the vacuum.
On my car it was the side facing down on the rubber lip that had holes, just on the edge to the plastic cup/piston it sits over.
I pumped vacuum up to 300 mm Hg on the meeter, after half an hour it was 250 and after one full hour 200.(at slightly above 200 the center comb flap started to close again.
I will keep you posted on how it works
/Peter
04-12-2007, 09:15 AM
#6
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The center and footwell actuators are the same diaphragm. As it is only the diaphragm that you are changing you only need to purchase the footwell actuators to get the diaphragms.
I sell the center for $78 and the footwell for $62 so there is a saving in buying the two footwell units.
Take out the diaphragms and throw the rest away unfortunatly.
I sell the replacments diaphragms for the recirculation and defrost actuators at $10 each.
Let me know if I can help?
Best,
Roger
I sell the center for $78 and the footwell for $62 so there is a saving in buying the two footwell units.
Take out the diaphragms and throw the rest away unfortunatly.
I sell the replacments diaphragms for the recirculation and defrost actuators at $10 each.
Let me know if I can help?
Best,
Roger
__________________
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
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928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
George Layton March 2014928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
04-12-2007, 03:03 PM
#7
Drifting
Originally Posted by Peter F
The center comb actuator is the most difficult to replace and also the most expensive of the actuators.
I repaired mine in the car, just removing the cap and spring, it is a bit tight but can be done relatively easy.
Since it is vacuum the repair on the outside will see no pressure just the vacuum.
/Peter
I repaired mine in the car, just removing the cap and spring, it is a bit tight but can be done relatively easy.
Since it is vacuum the repair on the outside will see no pressure just the vacuum.
/Peter
Very useful info Peter for which many thanks. Wish I'd have thought of trying this when I had the console out last week!
An advantage of your method is that presumably you didn't even have to fiddle with detaching/re-attaching the actuator arm, but just repaired the bladder without removing it? You must have very small/nimble fingers too...
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04-12-2007, 04:56 PM
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Thanks Roger,
I did get your email as well but since the actuators have been repaired and seems to hold enough vacum to operate properly I will give it a try before ordering new parts.
I tested the footwell actuator today and it was not as good as the comb actuator holding vacum.
I took it apart again and stretched the rubber bladder and could see some more week spots, no holes yet but it is on it's way out.
So I used some more rubber glue all orund the outside of the rubber and wrapped two turns of self vulcing tape to strengthen it.
(started with four but it caused it to bind in the plastic housing)
It is in test right now but after half an hour it still holds vacum enough to keep the footwell actuator open.
With regards to my fingers I wish they where smaller sometimes working on a 928
/Peter
I did get your email as well but since the actuators have been repaired and seems to hold enough vacum to operate properly I will give it a try before ordering new parts.
I tested the footwell actuator today and it was not as good as the comb actuator holding vacum.
I took it apart again and stretched the rubber bladder and could see some more week spots, no holes yet but it is on it's way out.
So I used some more rubber glue all orund the outside of the rubber and wrapped two turns of self vulcing tape to strengthen it.
(started with four but it caused it to bind in the plastic housing)
It is in test right now but after half an hour it still holds vacum enough to keep the footwell actuator open.
With regards to my fingers I wish they where smaller sometimes working on a 928
/Peter
