A/C ducts

Discussion in '1978 - 1981 Specific' started by Macsouthcarolina, Sep 20, 2020.

  1. Macsouthcarolina

    Macsouthcarolina Member

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    Seems to be a Lot of AC questions right now!

    I put in a new AC system in my 80 Z recently and am trying to figure the inside of the car stuff now. I got the system from original air and it’s like the factory set up. Couple issues I’m sure y’all can help me with.

    1. The connection between the upper air distributor and the lower air duct is not even close to fitting. From what I can find on the net it looks like there’s a gasket (pic) that goes around the lower. Is this enough to seal it off?

    2. The blend door? Doesn’t move. I assume the temperature slider on the control panel opens and shuts this? I see there’s a cable from the control panel to the door, maybe it broke? I assume this is why there's always heat coming out unless I turn the ac on?

    3 I assume there’s some vacuum control in the system too. Where’s this come into play?
     

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  2. Twisted_Metal

    Twisted_Metal Administrator Staff Member Lifetime Gold Member

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    BonzoHansen and Coadster32 like this.
  3. Macsouthcarolina

    Macsouthcarolina Member

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    Thanks for that!

    on the fit between the air distributer and lower air duct (pic I posted). Online it shows some foam with tape on one side, is thus supposed to seal it off? Those two pieces don’t look like they fit together at all.
     
  4. Twisted_Metal

    Twisted_Metal Administrator Staff Member Lifetime Gold Member

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    Yes... Those two pieces need to be sealed.
    You will lose a lot of air flow to the vents if they aren't sealed somehow.

    I'm tackling a heater core and A/C evaporator replacement in the next few weeks and haven't quite figured out what to use for a seal, yet.
    You may be able to wrap a piece of tape around them if you don't use a foam seal.

    Post up what you figure out.
     
  5. Macsouthcarolina

    Macsouthcarolina Member

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    Made some progress

    talked to a guy at Chicago muscle car parts about some gasket in the diagram. He confirmed that there was a pretty good gap there and that the gasket would seal it. Have the gasket on the way (circled in the diagram)

    ordered the vacuum reservoir ball and some vacuum line. Crossing my fingers that lines are still hooked up under the dash and will work once I get vacuum going. Wasn’t sure if the vacuum line size, thought I’d read 1/8 somewhere so I ordered that C6A8BF0E-65FA-477E-AB2E-87732F177677.jpeg
     
  6. Macsouthcarolina

    Macsouthcarolina Member

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    Got the reservoir tank and hooked up the vacuum (Holley sniper). The door is moving some but will not close all the way, I assume it should. Don’t think I have enough vacuum to operate the system. I can feel a little at the Passenger kick panel actuator. The actuator on the passenger side doesn’t seem to have vacuum when I remove that hose. Feels like good vacuum at the reservoir (don’t have a gauge). I’m assuming there’s a cracked Or unhooked hose somewhere? Anyway to check them at the firewall without removing the dash? I’ve got the instrument bezel out and that doesn’t seem to help. Made a video showing the door movement. Does go from cold air to heat.
     
  7. Macsouthcarolina

    Macsouthcarolina Member

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    Bought a cheap brake bleeder to check try and chase down the vacuum issue. When I apply vacuum at the firewall it won’t pull a vacuum at all. I hooked it up to both the actuators I could get to (kick panel and on the end of the heater box) and both of these held a vacuum but did nothing. I pulled the hvac controller and pulled the hoses off the back (there were 5 tubes). 2 held a vacuum, the other 3 would not. One of the tubes that held, made the outer door on the heater box Open all the way. Couldn’t tell that the other was doing anything.

    im thinking I’m going to have to remove the dash to get to firewall and see where my leak is. Any other ideas?

    how bad is the dash removal? I need a new one, might be the time
     

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  8. Twisted_Metal

    Twisted_Metal Administrator Staff Member Lifetime Gold Member

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  9. Twisted_Metal

    Twisted_Metal Administrator Staff Member Lifetime Gold Member

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    Can you post the dimension of the upper/lower duct seal when you get it?

    It looks like something that would be available at the local hardware store but I don't want to buy a roll that's the wrong size.

    Thanks, in advance!
     
  10. Macsouthcarolina

    Macsouthcarolina Member

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    Will do. I thought the same and looked on amazon. I was able to find the correct size, but in longer rolls for like $30. The 2 I bought were $10 each
     

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