My AC Conversion Thread

Discussion in 'Technical' started by facelessnumber, Jun 8, 2009.

  1. facelessnumber

    facelessnumber Drew Pittman

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    I've talked about it a few times, but unless the deal falls through I'm going to actually be doing this in the next few weeks. Full factory AC installation in a non-AC car. I will post questions, findings, progress pics, etc. in this thread, and hopefully when it's all done I will distill it all into a tech article.

    Here's the plan... I called my brother in Jackson to scope out a Comet at the Pull-A-Part for AC stuff. Instead he connected me with a friend of his who has a wrecked Maverick. It's a '73 with a package tray dash like my '71, factory 302 with AC. It has some relatively minor front end damage and has been parked for a while, couple of years I think. Before it was wrecked the AC had just been serviced and was in perfect working order. I might even be able to crank it up and test it.

    I called the guy to see about buying the parts, and we worked out a deal so nice I just can't pass it up. It so happens that he needs help with a transmission swap in his Celica, so if I give him a hand with that he'll give me the parts! He intends to put his Maverick back on the road eventually, but he'll let me swap every part I need for the AC conversion provided I leave him my non-AC parts. (effectively I'll be doing TWO conversions, so I may end up writing an "AC car into non-AC car" article too...)

    I've been trying to piece an AC system together for this car since I got it, and it's not been easy. If I did get everything together from used parts, there's no way to know it would work right away and there's no model to look at for installation. This way I'm taking a complete working system, pulling it and immediately installing it while it's all fresh on my mind how everything goes together. Really a stroke of luck I think, and an opportunity I shouldn't pass up.

    The car is in Jackson where my family lives, so I'll be taking a few days off work, staying at my parents' place while I do this. My father-in-law has the equipment to evacuate and fill the system, so really my only expenses will be refrigerant, gas money, o-rings, and maybe I might have to replace the receiver/drier, a hose or two, I'll need a new heater core... Nothing major. Certainly less than I'd spend on a Vintage Air or piecemeal stock system...



    So I'll begin this thread with the first of what may be several questions. This is a big job but as of now I think I know what I'm getting into except for one thing - Firewall differences. Is it going to be a matter of putting a couple of holes in the firewall for hoses, or are we talking about surgery? Has anybody got a good pic of an AC car's firewall?
     
  2. Grabber5.0

    Grabber5.0 Gear-head wannabe

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    The firewall modifications are relatively easy. You have to drill a few new holes for the heater hoses and a couple of the heater box studs, and fill a few others, or plug them. I chose to weld them up. Here is my thread with pics and details. Installing factory AC box in non-AC car

    I was going to do the same conversion, but I would rather convert to a Sanden compressor. I have all of the factory parts except for the condenser and receiver/dryer, but those are easily enough obtained. I hope to complete mine before the Gathering next month. Did not have time to do everything last year, my goal was just to get the car driveable, and I did not do anything with it after that. I started checking my factory AC parts last month to make sure everything is operational. Make sure you check all of the vacuum controls to make sure they don't leak.
     
    Last edited: Jun 8, 2009
  3. Jsarnold

    Jsarnold Senior Member

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    Great!

    I'll be following your thread closely. I also have a '72 302 with AC that's been sitting for many years. Had NO freon left in it. At some point I'll try to make it work. Be interested in what you do about conversion to newer refrigerant.

    Picture shows my 1972 Mav firewall with original 302 AC. I'll be happy to provide any measurements or other info on the stock setup.

    Jim
     
    Last edited: Aug 13, 2011
  4. Grabber5.0

    Grabber5.0 Gear-head wannabe

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    Interesting that the vacuum lines came out a different hole on your 72. I even see now the dimple in my firewall for that hole. Also note that I apparently filled in one of my brake line clip holes and one of the firewall insulation retainer holes. :huh:
     
  5. 71gold

    71gold Frank Cooper Supporting Member

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    what are you doing for the...defrost and center dash vent and are you changing out the controls and box also.

    when i did my AC i put everything new from firewall out, w/Sanden compressor.

    good luck...

    Frank
     
  6. facelessnumber

    facelessnumber Drew Pittman

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    Thanks for the info, guys. Looks like the firewall part will be pretty straightforward, as I'd hoped. Regarding refrigerant, I haven't decided yet. I may go with 134 if it's already been converted correctly, but more likely I'll try Freeze 12 or "Enviro-Safe." If possible though, I've got a friend who's licensed to buy R12 and I'm leaning in that direction.

    Frank, my plan is to use everything from the donor car, including the dash if I have to. I figure since both cars will be right there and I need to swap him my non-ac parts anyway, I'll do the whole conversion while I'm in Jackson, then fill it at my in-laws' house down there and drive back home nice and cool. I just need to anticipate whatever parts or supplies I can't get locally, and order them before I go.
     
  7. Jamie Miles

    Jamie Miles the road warrior

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    Freeze12 works well. My understanding is that it's just R134A with a different lubricant in it that's compatible with the R12 systems. Terry and I took that Chevy truck I'm buying to a local shop by his house and had them service the A/C. R12 system and they recharged it with Freeze12 after replacing a leaky schrader valve.. It was 90 degrees in the shop and the temp got down to 49 degrees at the vents with the truck sitting there idling. I found myself turning the A/C down a notch or two several times while driving down the road.
     
    Last edited: Jun 8, 2009
  8. Mavaholic

    Mavaholic Growing older but not up!

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    To change the dash, you have to pull the windshield. If your thinking of just cutting a hole in yours to install the center register, it will stick out a bit further than stock because there is a recess around the hole on the stock ac dash. Plus you will leave him a dash with a hole in it. I swapped a fact system in my 77 way back and it is pretty straight forward. Be very careful with that vacuum switch. After cooking under the dash for 35 years the plastic becomes brittle and they are prone to breaking the end cap off. If that happens, your screwed. All the doors are vacuum operated. When I did my swap, Green Sales had a nos switch so I got lucky. Another part that loves to break off is the condensate drain tube on the bottom of the ac box. Make sure you disconnect the rubber drain hose before pulling on the box. That hose is also a speciality hose. The end that sticks outside is flattened to prevent water from back flowing into the box, so carefully remove it. Dont cut it.
     
  9. Craig Selvey

    Craig Selvey Indiana State Rep - MCCI

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    There is also a piece of metal inside the drain hose.
     
  10. 71gold

    71gold Frank Cooper Supporting Member

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    check to make sure the waterpumps are the same...:yup:
    you will also need the...fan shroud ,fast idle solenoid (w/ wire) condenser and heater control valve......you may have to cut the hole in the radiator support for the hose.
    check the alts. to see if they will swap or need to be clocked for the compressor bracket. motor pulleys may be diff.
    get your camara and take a 1,000 pictures...:yup:
    ...have the...new heater core/old condenser...pressure tested before installing...:rolleyes:

    ...Frank...:Handshake
     
  11. facelessnumber

    facelessnumber Drew Pittman

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    Excellent, guys. It's great to have all this info in one place.

    Um, yeah... I'm not doing that then if I can avoid it. I can tell you how that's going to work out: Best case, I'm stuck out of town waiting for a windshield. More likely I'm stuck in the hospital waiting for a surgeon to sew my hand back on. Usually I'm not one to shy away from learning a new skill, but I don't think this will be a good time or place to teach myself about pulling windshields.

    This means either I need to cut a place for the center vent, or I need to omit/reroute it. Can someone post a pic of what exactly is behind the dash that relates to that center vent? My first gut feeling is to trim it back and run a duct to aftermarket vents in the package tray, but I don't know how feasible that would be. Next idea would be to block them off and let the other factory vents do the work.

    Let me guess... The vacuum switch is Maverick/Comet-specific and it's not reproduced. Thank you for that. You have convinced me that I need to secure a spare before I touch that. Are all of the factory AC vacuum switches through 77 the same?

    Noted. Thank you.


    Should be. My understanding is that this car is all stock, and I know my water pump is for a Maverick. Is there an AC/non-AC Maverick water pump? Either way, I will compare them. Didn't think of that one, thanks.

    I have a fat aluminum radiator with electric fan on the back of it. I was thinking if my fan doesn't pull enough air through the condenser, I'll put a small "pusher" fan on the front of it and wire that to the compressor with a relay. Thoughts on this?

    As for the fas idle solenoid... I have an Edelbrock/AFB carb. You think the stock solenoid will work with that linkage? I was expecting I might have to buy one specifically made for my carb. Last I checked Summit had these for about $80. More than I think it ought to be, but if I need one I need one...

    My alternator is mounted on the passenger side, and power steering pump is mounted low and out of the way on the driver's side, so I think I'm ok there. If not I will swap the brackets and pulleys over from the other car.

    Count on that!

    Good info there, Jamie. I keep hearing great things about Freeze12...
     
  12. maverick1970

    maverick1970 MCG State Rep

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    There should be a spacer in place on your power steering bracket that you remove to make room for the AC brackets.
     
  13. facelessnumber

    facelessnumber Drew Pittman

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    And there is... Good, thank you!
     
  14. flynbrd

    flynbrd Member

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    I'm in finally stages of my a/c repair which involved gutting out the old system and switching it for the new. Few things to note when installing the system.

    1. You'll need to wire in de-icer switch. Its the two prong switch, steel box shaped that sits on top of the heater/ ac box. As a steel tube going to the evaporator core.
    2. If the box is used pop it open, check the evaporator core for oil residue(residue would indicate the core was leaking), replace the heater core for peace of mind. Clear out the drain plug! Finally I would replace the blower motor also.
    3. Gently blew out the dust and cleaned the evaporator core.
    4. You can get foam kits to redo the box. About 15$
    5. TEST ALL VACUUM ACTUATORS! my new(being used) box was in awesome shape however the most of the vacuum actuators were bad. Lucky for me my old trashed box still had good ones.
    6. Use heater/ac controls from an a/c car of course, you can also get vacuum line kit for cheap 15$. This will replace everything you need.
    7. The heater/ac controls has one wire running down to the de-icer switch and from there to the a/c clutch switch on the compressor.(actually factory has it running through the fuse box)
    8. 3 vacuum lines run into the engine bay, 1. heater control valve 2. vacuum line 3. vacuum canister (get a comp vacuum canister off ebay, work far better than the stock one)
    9. Raid the donor car for the lower tray for vents, tubing, and dash pad.
    10. Buy a universal condenser off ebay. You'll spent 50$ for a condenser thats far superior to the stock replacement.
    11. Dryers are cheat, about 20$ I think.
    12. If you can swing it, run a rotary a/c compressor, sanden etc. I'm converting my 302 to run serpentine so the modern 5.0 compressor was a given.
    13. A/C shop is going to charge 60$ to make custom a/c lines for my system :thumbs2:
    14. Finally chill

    Hope this was ... kinda helpful.
     
  15. Jsarnold

    Jsarnold Senior Member

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    Great tips for rebuilding the AC. Will file it away for when I do mine. How about some sources for the inexpensive vacuum line kit, foam kit and $20 dryer. Thanks!!
     
    Last edited: Aug 13, 2011

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