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Thread: Project Summer Comfort - Refreshing factory A/C

  1. #1
    Serial old car rescuer Arne's Avatar
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    Project Summer Comfort - Refreshing factory A/C

    I've decided it is time to undertake the last semi-major task in the refresh-toration of my '72T coupe - reinstalling and upgrading the factory air conditioning. I put this on the back burner last year when I got the car assembled after the paintwork, as I had other things going on that seemed more important. But I had to skip a PCA drive over the weekend due to record-breaking heat here in Western Oregon, with highs around 110F. So it is time to get back to this.

    My goal is decently functioning A/C, but without getting too worked up about strict original appearance. I'm not expecting miracles, so ice-cold modern car A/C in all ambient temperatures is not required. I've done this before. After updating and slightly enhancing the A/C in my prior '84 Carrera it worked quite well, even in the 110-115F heat of the Central Valley of California. I should be able to get similar results in my '72, maybe even a touch better due to the '72 car's greater vent area.

    My car's A/C came with the car—mostly in boxes. The front condenser fan was sitting loosely in place, and the under dash vent plenum was still mounted, but all else was in boxes and bags. So the first step was to verify what I have and assess its condition. This is not as tough as it sounds. Here is a list of the main parts:

    • Compressor and mounting parts
    • Deck lid condenser
    • Front condenser, fan and mounting parts
    • Receiver/dryer
    • Evaporator box with expansion valve and blower fan
    • Under dash vent plenum with fan and temp controls
    • Hoses (5 pieces)

    After going through the boxes, I had all the main parts except the compressor and most of the compressor mounting brackets. The lack of compressor was no issue, as the old York piston type compressors are crude, inefficient (by today's standard) and power-robbing. So that was already on my replacement list. I did need the brackets, however.

    Most of the rest of the parts will also be replaced and upgraded, other than the deck lid condenser. I will re-use that part, as new ones are not functionally better. But the front condenser, receiver/dryer, evaporator w/expansion valve, thermostatic temp control and all hoses will be replaced. Both blower fans test fine, run at proper speed and are quiet. So I could reuse both of them. But they are still 50 years old, and in the case of the evaporator fan, if it needs replaced later I'd need to de-pressurize the system to get to it. So while I will reuse the original fan motor for the front condenser, I will replace the main fan motor with a modern upgraded unit.
    Last edited by Arne; 07-01-2021 at 03:25 PM.
    - Arne

    Mostly done
    - 1972 911T coupe, Silver Metallic, Fuchs, Appearance Group, F&R sway bars, factory installed Frankfurt, upgraded factory A/C.
    Sold - 1984 911 Carrera coupe, Chiffon white; 1973 914 2.0, Saturn Yellow; 1984 944, Silver Metallic

  2. #2
    Serial old car rescuer Arne's Avatar
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    While I didn't decide to get serious about completing this until now, I did do some prep work on the project over the past year or so. The compressor brackets were acquired and mounted. Some replacement vent louvers were sourced, and the vent plenum mounted under the dash.

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    - Arne

    Mostly done
    - 1972 911T coupe, Silver Metallic, Fuchs, Appearance Group, F&R sway bars, factory installed Frankfurt, upgraded factory A/C.
    Sold - 1984 911 Carrera coupe, Chiffon white; 1973 914 2.0, Saturn Yellow; 1984 944, Silver Metallic

  3. #3
    Serial old car rescuer Arne's Avatar
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    I also spent some time doing further assessment of the various parts I have, including test re-fitting to make sure I have all the hardware. Also tested and de-bugged the electrical circuits.

    The good news - after a small amount of troubleshooting, all the wiring is fine. The factory A/C installation included a small supplemental 2-circuit fusebox, mounted just above the main 10-circuit box. I noticed right away that this box was damaged, and worse, to deal with the damaged part someone had hot-wired (un-fused) the damaged circuit. At first I figured I'd need to buy a replacement fusebox, but after thinking this through a bit, I realized that since my car was not originally fully optioned, I had 2 or 3 unused circuits on the main fuseboxes. So I moved the two A/C circuits down into the main fusebox using the spots for power windows and sunroof that my car doesn't have. Cleaner installation overall, and no extra parts needed. I relabeled the inside of the fusebox cover appropriately.

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    After re-wiring the fusebox, connecting components, testing relays and finding one unplugged connection in the luggage compartment, everything electrical worked, mostly as it should. The fan switch was a bit flakey and had a mind of its own, so I acquired and installed a replacement. Same with the thermostat due to the original having a damaged capillary tube. So that part is now all figured out.
    Last edited by Arne; 07-01-2021 at 03:32 PM.
    - Arne

    Mostly done
    - 1972 911T coupe, Silver Metallic, Fuchs, Appearance Group, F&R sway bars, factory installed Frankfurt, upgraded factory A/C.
    Sold - 1984 911 Carrera coupe, Chiffon white; 1973 914 2.0, Saturn Yellow; 1984 944, Silver Metallic

  4. #4
    Serial old car rescuer Arne's Avatar
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    That pretty much brings us to the present. Time to order parts.

    For the '84 Carrera, when I went through this I used parts from RennAire (hoses, evaporator, front condenser) as they were a bit more affordable than the apparently similar parts from Griffiths. But while the end result on the Carrera was fine, I was not totally happy with the RennAire parts. The fit of the condenser and evaporator was not great, and RennAire's barrier hoses are "reduced diameter" hoses. This was claimed to be a plus, as they are lighter and more flexible, and so installation was supposed to be easier. But what wasn't mentioned is that none of the factory hose mount clips fit the reduced diameter hoses. So properly securing the hoses to the body took a lot more time than it should. And ordering from RennAire is a hassle as they don't even have all their parts listed online (ancient, never updated web page), and contacting them on the phone is difficult.

    Lesson learned. This time I've ordered all Griffiths parts. His compressor upgrade kit is very complete, and the upgraded condensers and evaporators he makes are said to fit like factory. The barrier hoses are also stock diameter throughout, so all the original mount clips should fit.

    Griffiths is currently running 2 weeks shipping lead time. I've ordered their compressor kit #3B and the front parallel-flow condenser direct. I ordered the Griffiths evaporator and upgraded fan motor from Pelican. There are a couple of advantages to getting those two parts from Pelican. First is that I used my annual 10% PCA discount, plus Pelican has free shipping. They also had those two items on the shelf, and they ship from here on the west coast so I'll have them by the end of the week. The parts from Griffiths will ship from NJ, so add 5-7 business days transit time to their 2 week lead time.

    So next will be complete refresh and upgrade of the evaporator box.
    Last edited by Arne; 07-12-2021 at 03:59 PM.
    - Arne

    Mostly done
    - 1972 911T coupe, Silver Metallic, Fuchs, Appearance Group, F&R sway bars, factory installed Frankfurt, upgraded factory A/C.
    Sold - 1984 911 Carrera coupe, Chiffon white; 1973 914 2.0, Saturn Yellow; 1984 944, Silver Metallic

  5. #5
    Serial old car rescuer Arne's Avatar
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    One last note - I am not going to add additional rear fender condensers to the system. Just mildly upgrading the factory 2-condenser equipment. Staying with the original 2 condensers on the light-colored (Chiffon White) Carrera was quite adequate for my needs and climate. So a similar approach to the light-colored (silver) '72T should be enough for me.
    - Arne

    Mostly done
    - 1972 911T coupe, Silver Metallic, Fuchs, Appearance Group, F&R sway bars, factory installed Frankfurt, upgraded factory A/C.
    Sold - 1984 911 Carrera coupe, Chiffon white; 1973 914 2.0, Saturn Yellow; 1984 944, Silver Metallic

  6. #6
    Serial old car rescuer Arne's Avatar
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    New evaporator and fan motor have an ETA of Friday. So I began disassembling, cleaning and prepping the evaporator box while waiting. No unpleasant surprises yet...

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    - Arne

    Mostly done
    - 1972 911T coupe, Silver Metallic, Fuchs, Appearance Group, F&R sway bars, factory installed Frankfurt, upgraded factory A/C.
    Sold - 1984 911 Carrera coupe, Chiffon white; 1973 914 2.0, Saturn Yellow; 1984 944, Silver Metallic

  7. #7
    Looking forward to following this thread, Arne !!
    George Kehler in Tennessee

    1955 356 coupe
    1971 911S (knee deep in restoration)
    1997 993 Targa

  8. #8
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    Thanks for starting this thread as well - I'm planning to do this exact same project soon. Currently trying to decide what original parts to keep vs upgrade. I do wish Frank Beck or someone else would have come through with red fabric replacement (barrier) hoses, but looks like those efforts are all dead.
    Last edited by cwrm4; 07-01-2021 at 06:56 AM.
    '70 911T Coupe
    '93 964 C2 Coupe

  9. #9
    Serial old car rescuer Arne's Avatar
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    Yes, if red hose was available I would have re-worked my plan to stay with a York/Tecumseh compressor for period looks. But since I can't have red hoses, I figure there's no need to use less effective parts just for a partial period appearance. Might as well just make it as effective as I can instead.

    As for reusing original parts, the rear condenser is really the only one I figure is worth keeping, since replacements are not functionally better. And even there, my wife is not sure that's wise. She would rather see all of it be new.
    - Arne

    Mostly done
    - 1972 911T coupe, Silver Metallic, Fuchs, Appearance Group, F&R sway bars, factory installed Frankfurt, upgraded factory A/C.
    Sold - 1984 911 Carrera coupe, Chiffon white; 1973 914 2.0, Saturn Yellow; 1984 944, Silver Metallic

  10. #10
    Serial old car rescuer Arne's Avatar
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    Another change in plan. After explaining to my wife why it was not necessary to replace the rear condenser, I then grabbed the original out of storage so that I could flush it and reinstall it on the car. And I thought it odd that all of the other A/C hoses were neatly coiled up, labeled and placed in boxes when removed, except the short one between the rear condenser and compressor. That hose was still attached to the condenser.

    I spent 15-20 minutes trying to remove the hose non-destructively. Failed. The hose is seized tight, and all attempts to break it loose either round off the flats on the condenser fitting and/or want to twist the tubing.

    Not worth messing with any further. So I now have a rear condenser on its way as well. That means that the refrigerant circuit will be entirely new. The only part that cools or moves that will be reused is the front condenser blower fan motor.
    Last edited by Arne; 07-03-2021 at 08:59 PM.
    - Arne

    Mostly done
    - 1972 911T coupe, Silver Metallic, Fuchs, Appearance Group, F&R sway bars, factory installed Frankfurt, upgraded factory A/C.
    Sold - 1984 911 Carrera coupe, Chiffon white; 1973 914 2.0, Saturn Yellow; 1984 944, Silver Metallic

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