A/C System Repair/Retrofit

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Our DisclaimerIROCZONE.com, its affiliates, owners and members, claim no responsibility of damage to your AC system or any other component of your vehicle as a result of using the following documentation.  By proceeding, you agree that there may be some error in documentation and you will assume all risks from here on out.  We recommend that if any AC work is to be done, that your vehicle should be taken to a local repair shop.  These instructions are for educational purposes to show what is involved in retrofitting an AC system correctly, versus one of those cheap kits you buy at Wal*Mart that don’t work worth a dime.

Please read the following link to understand how and air conditioning system works.  I’m sure this information will prove to be helpful in performing the retrofit.  We strongly recommend it!  AIR CONDITIONING SYSTEMS

So your A/C has called it quits and it’s summer. Welcome to the club. It’s due time our cars start to deteriorate and the A/C system is no exception. But what do you want to do? Our systems were originally equipped with CFC R-12 refrigerant, which is not only now difficult and costly to obtain, you must be EPA 609 certified to buy it.

This project will explain basic A/C repairs and retrofitting our cars to the new, non-CFC refrigerant, R-134a. Why should you retrofit? Well, we’re not going to tell you to retrofit. It is a time consuming, sensitive project that must be done carefully. By all means, R-12 is a much better refrigerant and if all you need is a top-off, then we would recommend sticking with R-12 as it would be a cheaper fix since it IS still available in most areas. If there is any system damage (busted hoses, lines, leaking or bad compressor, leaking or damaged condenser, etc.) that requires opening the system for repair, you may want to consider retrofitting. If a situation arises that a compressor needs to be replaced, chances are, it would be cheaper to buy the tools you need and retrofit yourself then it would be to have an A/C shop do the repairs with R-12 or even have them retrofit to R-134a for you. Plus, the next time you need to do any repairs to any other vehicles, you’ll already have the tools (and experience).

Although, most people experience better cooling with R-12, we’re going to show you some tips and tricks to get the most out of your R-134a conversion for our particular vehicles. We won’t guarantee it’ll be just as good, but damn close! Plus, next time you need to repair your system for anything, you’ll already be converted and R-134a refrigerant will be a lot more easily obtainable and cheaper.

SUMMARY: Do NOT use kits from local discount stores.  They DO NOT WORK!  I only recommend ACSource.com and ACKits.com due to quality of services and parts.  IROCZONE does NOT receive any compensation for mentioning their names.  Only from experience and rave reviews from many other people that have used their parts and services.  If you feel like cutting corners or going with cheap parts, I suggest you stop here and take your car to a professional.  I have tried the cheap way and it ended up costing me more in the long run.  Please pay close attention to the following directions as they are based on real experience, not guess work.

If your system is under pressure (still has R-12 in it), you should have it recovered by an A/C shop. Intentional venting of CFC refrigerants is highly illegal and is subject to a $25,000 fine by the EPA … we didn’t make it up.

Parts Needed (Minimum):




R-134a compatible, XH-7 or XH-9 desiccant.  About $33 plus shipping from ACKits.com.  Stores cost about $40 to $50.


An absolute must in a retrofit. If you don’t feel like spending the money on this replacement part, stop now and don’t continue. We’re serious!  ACKits.com sells these at good prices.




Green, R-134a compatible, complete set for ALL parts you can access.  The complete set is most recommended.  It’s better to have more than not enough.  About $30 for a whole set with more than just O-Rings.

O-Ring Lube

  • Generally, coating the O-Rings with AC oil helps in sealing the lines.  To prevent breakdown of the O-Ring material and help connections last longer, we recommend Nylog O-Ring lube from ACSource.com.  It’s only a few bucks more.


  • PolyAlpha+ from ACSource.com or 
  • Texaco Capella HFC 100 (POE) from ACKits.com or
  • POE (Polyol Ester) 100 oil from most automotive distributors if you don’t feel like ordering online.

TIP: We strongly recommend either the first or second item. It’s worth the wait. And while you’re at it, you can order all of the tools and other replacement parts at the same time. Let’s take our times on this … it’ll last a lot longer if you do it right the first time!  Oils cost about $5 for 8oz or $12 per quart.




Low side port 7/16" (20 threads) Less than $3

  • High side port 3/8" (24 threads) Less than $3

TIP: We’ve heard this way too often. "Best kind of adapter is no adapter. Second best are made of brass." Keeping this in mind, we recommend brass adapters from ACSource.com. They are much cheaper than what you’d find anywhere else and have their own Schrader valve (to replace the old worn out ones in your system). If you bought one of those cheap retrofit kits with the adapters included (Interdynamics), DO NOT USE THOSE ADAPTERS! They are cheap aluminum and use the existing Schrader valves. They would do better in the trash!  You have been warned!

Orifice Tube

  • GM standard Orifice Tube, for our application, is 0.72 White or White/Black (designed for R12).  TIP: The GM 0.72 Orifice Tube will work, however, research and experience have found that using the Ford 0.67 Blue Orifice Tube provides better performance for our retrofitted cars due to the smaller opening (for the smaller molecular makeup of R134a compared to R12).  A better regulated flow into the evaporator proves to have better and more efficient cooling.  We recommend the Ford 0.67 Blue Orifice Tube for this application.  These should be available at most automotive stores (NAPA) or other local automotive AC shops.  If needed, ask for one for an 82 to 89 Ford Thunderbird w/ 302 CID V8.  You can also order one online at ACKits.com or if you prefer a kit of multiple sizes for different applications, ACSource.com has these.  They run about $2 to $5, depending on where you buy it.


Refrigerant 134a 

  • 3 to 4, 12 oz. Cans (depending on location, anywhere from $4 to $8 per can)

No special brand, Dupont Seva, Interdynamics, etc.


Tools needed:

Vacuum Pump (Electric)

  • Buy one, borrow one, rent one. You need one capable of pulling to near 30" of vacuum.  Prices range from $250 to $350, depending on the power you want (from 1.5 CFM to 6 CFM).  


: There are venturi type pumps out there that operate on compressed air. Although they are much cheaper than an electric one, they take one hell of a beating on your air compressor. Not only that, your air compressor should be able to maintain 90 PSI @ 4 CFM. If you decide to buy a venturi pump, DO NOT BUY HARBOR FREIGHT! They will not do the job. A Robinair pump from ACSource.com works very well with the right compressor. We still recommend spending the extra money and buying an electric pump. If you can’t afford it and you only plan on doing this job once, borrow one or rent one from somewhere.


Pressure Gauges

  • R-134a Compatible.  High and low side manifold gauge set.  These are also available at ACSource.com at a reasonable price.  Charging with only one gauge is a big NO.  We STRONGLY recommend picking up a decent manifold gauge set for high and low side readings plus a hook up for vacuuming and adding refrigerant.  Good set of Yellow Jacket gauges are about $100, well worth the investment!


Vent Thermometer

  • Available at most automotive parts stores for less than $10.


R134a Can Tap

  • To hook cans up to your manifold set.  Generally around $10 for a good quality tap.

Miscellaneous Items:

AC System Flush

  • Available at ACSource.com or some local AC shops.  About $12.50 per can.

TIP: Brake Cleaner has been suggested as an alternative use.  It leaves no reside but it WILL destroy plastic parts so if you use it, be very careful as to not get it on paint and plastic parts.  If you can, get the AC Flush and gun specifically designed for this use.  Whatever you decide to use, DO NOT FLUSH WITH WATER!!!

Replacement Parts (Optional)

  • Any parts that may have failed, hence is why retrofitting is being considered.  Leaks in condensers, evaporators, compressor failures, etc.  One thing is for certain;  If you need to purchase a compressor, PLEASE do NOT go to any local discount auto parts stores for most of them sell rebuilt compressors that have a HIGH failure rate.  Stay away from chain store remanufactured compressors.  You have been warned, again!!!  If you can’t go new and need to go rebuilt, we STRONGLY recommend one from ACKits.com.  You may need to order the clutch separately for those with serpentine belt systems.  Heed this advice … we only want to do this once!  A rebuilt Harrison R4 sells for about $133 plus shipping at ACKits.com.  They didn’t mention core charge, but keep that in mind.

Click [Next] to continue …

Allan Reinike

If you would like to contribute your projects to IROCZone.com, e-mail us at info@iroczone.com!

17 Responses to “A/C System Repair/Retrofit”

  1. keith says:

    the next page will not com up could someone email the article

  2. Marty says:

    Please fix the page Links from this article that when you click on next it just takes you back to the 1st page.
    projac01.html projac02.html projac03.html projac04.html
    Click [Next] to continue …

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  4. I agree with everything thats been said so far about the electrics, remember grounding is our friend. Take the time to clean and protect EVERY connection . Another quirk these cars have is crankshaft runout when they get into high mileage find a mechanic that really knows these cars .Going forward this step will prove invaluable ,good luck and have fun.

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