72 AC Vacuum line connection and routing

1971 - 1974 Mopars

  1. Robliepse

    Robliepse FBBO Gold Member FBBO Gold Member

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    I'm trying to figure out where I should connect the AC vent control vacuum line on my 440. I also need to know where the vacuum line goes through the firewall. The AC is one of the final parts of my 5 year restoration project

    AC Lines.jpg lines 2.jpg
     
  2. Nacho-RT74

    Nacho-RT74 FBBO Gold Member FBBO Gold Member

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    The hose goes from the vacuum tee on manifold through a grommet between brake booster and driver side inner fender. Same grommet used for the heater valve cable
     
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    • 72RoadrunnerGTX

      72RoadrunnerGTX Well-Known Member

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      On a ’72, the hose passes through a hole below the A/C fan opening, near the A/C box drain on the passenger side. Large grommet molded to the original vacuum line. The connection would be at the same manifold fitting as the brake booster.
      Firewall.jpg
       
      Last edited: May 16, 2019
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      • SureGrip

        SureGrip FBBO Gold Member FBBO Gold Member

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        I love you, man!! :thumbsup:
         
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        • 1972GY8SE

          1972GY8SE FBBO Gold Member FBBO Gold Member

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          I have been searching this topic for months!
          On my 72 Charger with A/C a vacuum hose runs through the same grommet as the heater control cable. it is connected to the small port at the brake booster fitting and feeds the HVAC control head.
          I think the one under the A/C fan is for models with vacuum controlled heater valves. the firewall shown is a e-body. I studied that same picture.

          20190517_182748.jpg 20190517_182755.jpg
           
          Last edited: May 17, 2019
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          • 1972GY8SE

            1972GY8SE FBBO Gold Member FBBO Gold Member

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            Here is my 72 Charger firewall.

            Capture.PNG
             
          • 1972GY8SE

            1972GY8SE FBBO Gold Member FBBO Gold Member

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            Confusing thing is on my car, the grommet under the A/C box appears it had a hose through it at one time. pic is from inside the car.

            IMG_20180218_122012.jpg
             
          • 72RoadrunnerGTX

            72RoadrunnerGTX Well-Known Member

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            The ’71-72 B-body firewall, inner fenders, and front frame rails are basically the same stampings as ’70-74 E-bodies. The holes used varied a bit depending on equipment. The picture posted is the same as the ’71 & 72 B-body. The labeling is accurate for A/C cars with one exception, shows three small screw holes around the grommet hole for the A/C vacuum supply, never seen that.

            So, two Charger guys indicate the vacuum supply line combined with the water valve cable, never seen that way from the factory.
            BTW, the original water valve cable hole is about a ½” in size, no way it would allow a vacuum hose to pass through with the original cable in the same ½” hole with a grommet.
            20190517_200425.jpg
             
            Last edited: May 18, 2019
          • 72RoadrunnerGTX

            72RoadrunnerGTX Well-Known Member

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            That is the original supply line
             
          • 1972GY8SE

            1972GY8SE FBBO Gold Member FBBO Gold Member

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            Well sir you are correct, I just went out and checked and there is no way that grommet will fit in the correct hole. I had it in the larger washer hole before and it was loose, solves the mystery for me.
            Thanks for the info and correcting the wrong information.
            BTW, the grommet part number is 3431279. its a Mopar number for a vacuum harness.
             
          • 1972GY8SE

            1972GY8SE FBBO Gold Member FBBO Gold Member

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            Last edited: May 18, 2019
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            • Nacho-RT74

              Nacho-RT74 FBBO Gold Member FBBO Gold Member

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              Well on my 74 is like that and a 73 of a friend of mine the same. Maybe a 73/74 diff with 71/72. Never have paid attention of that on my buddies 71/72s actually
               
            • 1972GY8SE

              1972GY8SE FBBO Gold Member FBBO Gold Member

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              What hole does it use?
               
            • Nacho-RT74

              Nacho-RT74 FBBO Gold Member FBBO Gold Member

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              My car? The one I’m describing, a hole between inner fender and brake booster. And the same grommet you shown on pic carrying heater valve cable and vacuum hose for the AC actuator system

              Charger 74.

              The hole for manual washer is unexistent on 73/74 because all were electric. And cruise control hole is on a diff location too. My car gets there the AC harness ( 74s run those out of the bulkhead )
               
              Last edited: May 18, 2019
            • 1972GY8SE

              1972GY8SE FBBO Gold Member FBBO Gold Member

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              Found this grommet, installed it next to the speedo cable, fits perfect.
              Thanks 72GTX.
              Now where does that pesky hood release cable go?

              20190518_143629.jpg 20190518_141342.jpg
               
              Last edited: May 18, 2019
            • rrTor-Red

              rrTor-Red FBBO Gold Member FBBO Gold Member

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              I have those three holes on my car. When I took it apart, I wanted to make sure I kept the grommet and screws together because that grommet isn't repopped anywhere that I know of. They go, at least one if not both, to the vacuum can under the battery tray on my '71. That is, if memory serves me right :)
               
            • 72RoadrunnerGTX

              72RoadrunnerGTX Well-Known Member

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              I saw another picture with the holes, sounds like the ’71 A/C two hose grommet is secured with screws. None of my ‘72s with single hose grommets had screws or holes. Yea, the ’71 A/C with a vacuum actuated water valve also had a vacuum reservoir under the battery box. The ’72 and later, with a cable operated water valve, did not.
               
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              • 1972GY8SE

                1972GY8SE FBBO Gold Member FBBO Gold Member

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                What hole does that cable use?
                 
              • 72RoadrunnerGTX

                72RoadrunnerGTX Well-Known Member

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                cables.jpg
                Hood cable hole.jpg
                DSC00200.JPG
                 
                Last edited: May 19, 2019
              • 1972GY8SE

                1972GY8SE FBBO Gold Member FBBO Gold Member

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                Thanks, on my way to garage.
                maybe its covered by the insulation.
                 
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