HVAC Head Removal 78
#16
Race Car
If this is a manual heater with cable you need to remove the clip holding on to the A/C console. This is a pain to get back on!!
On the 80 if you remove the vacuum lines as an assembly good luck with the vacuum hose placement. I have that all worked out with mine I can turn the head enough to get it out. But if you remove both side carpet areas, two screws holding the console on rear side bolt in glove box, two mounting bolts on center vent and two screws on bottom of console attaching to dash you can move it enough for reconnection.
My center trim piece comes out and all the screws are there, not sure why your screws are on the inside. The hardest part is reconnecting the heater cable and making sure all vacuum lines are connected. That is why I moved the console back about 4-inches to get everything in place first then mounted the air control box.
On the 80 if you remove the vacuum lines as an assembly good luck with the vacuum hose placement. I have that all worked out with mine I can turn the head enough to get it out. But if you remove both side carpet areas, two screws holding the console on rear side bolt in glove box, two mounting bolts on center vent and two screws on bottom of console attaching to dash you can move it enough for reconnection.
My center trim piece comes out and all the screws are there, not sure why your screws are on the inside. The hardest part is reconnecting the heater cable and making sure all vacuum lines are connected. That is why I moved the console back about 4-inches to get everything in place first then mounted the air control box.
#17
Rennlist Member
Yep
That is exactly what I ran into.......and that's why the screws are on the other side. Didn't take them very long to figure out that was a bad idea......
#18
Basic Sponsor
Rennlist
Site Sponsor
Rennlist
Site Sponsor
Thread Starter
What a difference a year makes.
I want to fully understand the vacuum layout and flap control so I am going to pull the console to play around.
Thanks for the help. I will post pictures and I have the vacuum layout.
The reason I am doing this is that I have a very restricted air flow when the AC is on. AC is ice cold (thank you Sean) but with a 110F ambient there is not enough air flow coming from the vents. There are two flaps that divert air to the heater matrix. My educated guess is that they open and making the cool air pass through the heater matrix and reducing flow in some way. Going to find out.
We thought it was the blower so we rebuilt a later style blower with a new motor and put that in. Rebuild motor worked great but no increase in air flow.
I want to fully understand the vacuum layout and flap control so I am going to pull the console to play around.
Thanks for the help. I will post pictures and I have the vacuum layout.
The reason I am doing this is that I have a very restricted air flow when the AC is on. AC is ice cold (thank you Sean) but with a 110F ambient there is not enough air flow coming from the vents. There are two flaps that divert air to the heater matrix. My educated guess is that they open and making the cool air pass through the heater matrix and reducing flow in some way. Going to find out.
We thought it was the blower so we rebuilt a later style blower with a new motor and put that in. Rebuild motor worked great but no increase in air flow.
__________________
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission? George Layton March 2014
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 2014
928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
#19
Rennlist Member
Several possibilities. It might be that your hoses are misconnected on the back of the head such that the flap from the blower is shut when in AC position. Is flow always restricted or just when AC is on? If it is always restricted then it might just be that the blower shut-off actuator is bad. Might also be to do with the mixture cable, although I kind of doubt it. Personally, I don't see any value to the blower shut off actuator and would not hesitate to ty-wrap it in position. You will want your mity-vac handy. No substitute.
#20
Basic Sponsor
Rennlist
Site Sponsor
Rennlist
Site Sponsor
Thread Starter
Mighty vac in hand no problem.
Blower shut off actuator - is that the one on top of the plenum just next to the blower?
I thought that in someway it diverted air for max defrost but after looking at the schematic it shuts air off - you are right I see no reason for it. We already have the recirc to stop bad air (skunk) entering the cabin.
Blower shut off actuator - is that the one on top of the plenum just next to the blower?
I thought that in someway it diverted air for max defrost but after looking at the schematic it shuts air off - you are right I see no reason for it. We already have the recirc to stop bad air (skunk) entering the cabin.
#21
Addict
Rennlist Member
Rennlist Member
Rog,
Did you or Sean clean out the condenser as in the other thread out there right now??
My 79 never pushed that much air either, but I wonder if there is 30 years worth of junk jammed in there under the blower motor.
Did you or Sean clean out the condenser as in the other thread out there right now??
My 79 never pushed that much air either, but I wonder if there is 30 years worth of junk jammed in there under the blower motor.
#22
Basic Sponsor
Rennlist
Site Sponsor
Rennlist
Site Sponsor
Thread Starter
Chuck,
You mean the evaporator - cleaned that as well as all the leaves and crap from under and around the blower motor.
So is low air flow an issue with earlier cars? Same blower as in the later cars but the amount of air is at least four times better. In this case the earlier blower was changed out for a later style with a new motor. They both (early and late) pushed the same volume of air. Just not making it to the passengers.
You mean the evaporator - cleaned that as well as all the leaves and crap from under and around the blower motor.
So is low air flow an issue with earlier cars? Same blower as in the later cars but the amount of air is at least four times better. In this case the earlier blower was changed out for a later style with a new motor. They both (early and late) pushed the same volume of air. Just not making it to the passengers.
#23
Rennlist Member
Not only can you clean everything on the '78 console after removal, but you can mix up lots of epoxy glue and build up cracked and broken things!
And the vacuum hoses are easy with the workshop diagram.
And the vacuum hoses are easy with the workshop diagram.
#24
Addict
Rennlist Member
Rennlist Member
Chuck,
You mean the evaporator - cleaned that as well as all the leaves and crap from under and around the blower motor.
So is low air flow an issue with earlier cars? Same blower as in the later cars but the amount of air is at least four times better. In this case the earlier blower was changed out for a later style with a new motor. They both (early and late) pushed the same volume of air. Just not making it to the passengers.
You mean the evaporator - cleaned that as well as all the leaves and crap from under and around the blower motor.
So is low air flow an issue with earlier cars? Same blower as in the later cars but the amount of air is at least four times better. In this case the earlier blower was changed out for a later style with a new motor. They both (early and late) pushed the same volume of air. Just not making it to the passengers.
I wonder if it's a function of the alternator not puting out enough juice as well.
My volt gauge would always crater when the AC was on. Especially at night, Lights would dim, blower motor slower, etc.