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air-conditioning question.

P peterfenlonMember
We don't generally need an A?C here in the UK, but there are times (FEW I KNOW) when it would be a luxury, I have all the original AC equipment on 3840, and I was told by a local garage with 2 De Tomaso's in stock that new seals could be fitted to the original compressor and I wondered if anyone can expand on just what I need to make the system accept the new fluid and not R12?, also where can I buy the parts from in the USA.

regards Peter
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lousbbylousbbyMember
I also have the stock york style compressor. You can buy a retrofit kit to switch from R12 to R134. You need to remove the schrader valve from the old nipple that you add freon to and screw on the new nipple that comes with the kit. I have done this conversion to a few of my cars. If your budget allows I would upgrade to the newer aluminum compressor Bosswrench mentioned.
P peterfenlonMember
quote:
Originally posted by Bosswrench:
First, what compressor are we talking about? Stock was an iron York which dates back to the late '50s and is a single-cylinder compressor and weighs 38 lbs. The one most people retrofit is a Sankyo 508 with is aluminum, quite small and weighs 16 lbs with Sankyo's adapter bracket. All stock hoses bolt on.

I should have said that my car has all the original A/C equipment I wasn't aware that it was so old, a 50's item! Its hard enough to get parts to the UK and a set of seals is preferable to an update to a new compressor, cost is a factor here, not every Pantera owner can afford all the updates that are out there. We also have tax to pay on imports which, when turned around our American UK car owners when buying parts don't have to. I agree that it would be good to go to newer compressor but I would like to keep the car as I bought it if at all possible.

best Peter
panterrorpanterrorMy 74 GTS
quote:
Originally posted by Peter Fenlon:
We don't generally need an A?C here in the UK, but there are times (FEW I KNOW) when it would be a luxury, I have all the original AC equipment on 3840, and I was told by a local garage with 2 De Tomaso's in stock that new seals could be fitted to the original compressor and I wondered if anyone can expand on just what I need to make the system accept the new fluid and not R12?, also where can I buy the parts from in the USA.

regards Peter


Peter,

Many will tell you all that is required to convert from R-12 to R-134 is to change the compressor seals, hoses, and expansion valve but while this is for the most part true, it significantly trivializes the task and actually doing the job properly is quite involved.

The OE/R-12 hoses need to be changed because they are made of a material and have fittings that cannot adequately contain the smaller R-134a molecule. Some report that after use R-12 hoses become laden with use they can work marginally in this regard but if yours are original, I’d say the chances of them retaining an R-134a charge for more than a few days or weeks are remote. I bought the fittings and barrier hose and made my own hose assemblies. The beadlock style AC fittings have a crush sleeves that retain the hoses on the barbs that need to be crimped. I have a crimper but most AC shops will do the job for you for a nominal fee if you make the hoses and bring them to them. I bought the hose, fittings, desiccant drier, and trinary switch in a kit with extra length hose for $120. I think you’ll find that both removing and reinstalling the hoses will take considerable effort.

If your car has the OE hose routing, the hoses in the engine compartment are all easily accessible but the two others are routed through the firewall and tunnel on their way to the evaporator under the dash. You will need to remove the interior seats, firewall, and center console, and I would tell you the dash as well. Some folks report they have managed to route the hoses and swap the expansion valve mounted on the evaporator without removing the dash but they are better men than I am. The expansion valve will be encased in tarred cork and I couldn’t manage to get wrenches on it or the hoses with the dash in. It wasn’t easy even with the dash removed.

The R-134a hoses use O-ring fittings instead of flares. Your OE condenser and evaporator coils will have flared fittings as will your OE compressor. You can by adapters or just buy flare fittings for those connections, which in your case will be pretty much every single connection except maybe the desiccant drier which should be replaced. As some advice, the typical R-12/R-134a fitting adapters are usually just the cone of a flare with a step on the other end that allows you to connect R-134a O-Ring fittings to a flare fitting when the adapter is installed inline. The problem with this is you still have the metal/metal sealing surface on the flares and you are really no better off in regard to sealing than just using a flare fitting. However, if you chuck up the adapters in a lathe, cut a small O-ring groove in the conical face, then polish the mating flare surface of the flared tube a bit, you should have an adapter that contains R-134a just as well as the spec O-ring fittings. This is especially helpful on the high pressure side fittings.

Some would question whether the OE Pantera condenser and evaporator coils are up to the task with R-134a use with the stock coils but I think they’ll be just fine, especially for your climate if a good job is done on converting the rest of the system. Replacement coils would easily double the cost of R-134a upgrade and increase the labor required.

You should buy a new desiccant drier anytime you open your AC system. These are inexpensive. Your binary switch is probably OK but you should check it. They are also inexpensive and in most OE installs will be located in line by the evaporator. As I mentioned, I received new ones with the hose kit I purchased.

You can rebuild your OE compressor with compatible seals but you should check into the price of the rebuild kit and invested time versus buying a contemporary 5 piston rotary compressor. These can be had for ~$130, or $250+ if want a Sanden branded compressor. There are mounting adapters you can buy that allow these compressors to be mounted to the OE Pantera AC mount, typically for $40-$50. As was also mentioned, you may also be able to enjoy a considerable weight savings with a new compressor.

The lubricants used in R-12 and R-134a systems are not compatible. If you are rebuilding your compressor, the old lubricant can be easily cleaned. You should consider flushing your OE condenser and evaporator coil with refrigerant solvent to remove any residual oil. This can be done in place without removing them. You can probably get by without doing so, but by the time you read perform the rest of the task, you’ll probably conclude why not.

I sourced all my bits because it was a custom install with the condenser relocated to the front and other custom components but I suspect some of the Pantera vendors have conversion kits to do the above for OE configurations. However, it still requires all the associated labor.

Once you get everything buttoned up, the system needs to be pulled down to vacuum for a period of time then charged with refrigerant and lubricant. This requires specialized equipment that sometimes can be rented or merely bring your completed car to a qualified service center.

If you do all that is described above, you’d likely have a system that would work on demand for a number of seasons. Without the attention to detail, it may require recharging multiple times per year. It just depends on how leak tight of a system you can achieve.

If you are still interested in tackling the task, I can list sources.

Best,
K
P peterfenlonMember
quote:
Originally posted by Panterror:
quote:
Originally posted by Peter Fenlon:
We don't generally need an A?C here in the UK, but there are times (FEW I KNOW) when it would be a luxury, I have all the original AC equipment on 3840, and I was told by a local garage with 2 De Tomaso's in stock that new seals could be fitted to the original compressor and I wondered if anyone can expand on just what I need to make the system accept the new fluid and not R12?, also where can I buy the parts from in the USA.

regards Peter


Peter,

Many will tell you all that is required to convert from R-12 to R-134 is to change the compressor seals, hoses, and expansion valve but while this is for the most part true, it significantly trivializes the task and actually doing the job properly is quite involved.

The OE/R-12 hoses need to be changed because they are made of a material and have fittings that cannot adequately contain the smaller R-134a molecule. Some report that after use R-12 hoses become laden with use they can work marginally in this regard but if yours are original, I’d say the chances of them retaining an R-134a charge for more than a few days or weeks are remote. I bought the fittings and barrier hose and made my own hose assemblies. The beadlock style AC fittings have a crush sleeves that retain the hoses on the barbs that need to be crimped. I have a crimper but most AC shops will do the job for you for a nominal fee if you make the hoses and bring them to them. I bought the hose, fittings, desiccant drier, and trinary switch in a kit with extra length hose for $120. I think you’ll find that both removing and reinstalling the hoses will take considerable effort.

If your car has the OE hose routing, the hoses in the engine compartment are all easily accessible but the two others are routed through the firewall and tunnel on their way to the evaporator under the dash. You will need to remove the interior seats, firewall, and center console, and I would tell you the dash as well. Some folks report they have managed to route the hoses and swap the expansion valve mounted on the evaporator without removing the dash but they are better men than I am. The expansion valve will be encased in tarred cork and I couldn’t manage to get wrenches on it or the hoses with the dash in. It wasn’t easy even with the dash removed.

The R-134a hoses use O-ring fittings instead of flares. Your OE condenser and evaporator coils will have flared fittings as will your OE compressor. You can by adapters or just buy flare fittings for those connections, which in your case will be pretty much every single connection except maybe the desiccant drier which should be replaced. As some advice, the typical R-12/R-134a fitting adapters are usually just the cone of a flare with a step on the other end that allows you to connect R-134a O-Ring fittings to a flare fitting when the adapter is installed inline. The problem with this is you still have the metal/metal sealing surface on the flares and you are really no better off in regard to sealing than just using a flare fitting. However, if you chuck up the adapters in a lathe, cut a small O-ring groove in the conical face, then polish the mating flare surface of the flared tube a bit, you should have an adapter that contains R-134a just as well as the spec O-ring fittings. This is especially helpful on the high pressure side fittings.

Some would question whether the OE Pantera condenser and evaporator coils are up to the task with R-134a use with the stock coils but I think they’ll be just fine, especially for your climate if a good job is done on converting the rest of the system. Replacement coils would easily double the cost of R-134a upgrade and increase the labor required.

You should buy a new desiccant drier anytime you open your AC system. These are inexpensive. Your binary switch is probably OK but you should check it. They are also inexpensive and in most OE installs will be located in line by the evaporator. As I mentioned, I received new ones with the hose kit I purchased.

You can rebuild your OE compressor with compatible seals but you should check into the price of the rebuild kit and invested time versus buying a contemporary 5 piston rotary compressor. These can be had for ~$130, or $250+ if want a Sanden branded compressor. There are mounting adapters you can buy that allow these compressors to be mounted to the OE Pantera AC mount, typically for $40-$50. As was also mentioned, you may also be able to enjoy a considerable weight savings with a new compressor.

The lubricants used in R-12 and R-134a systems are not compatible. If you are rebuilding your compressor, the old lubricant can be easily cleaned. You should consider flushing your OE condenser and evaporator coil with refrigerant solvent to remove any residual oil. This can be done in place without removing them. You can probably get by without doing so, but by the time you read perform the rest of the task, you’ll probably conclude why not.

I sourced all my bits because it was a custom install with the condenser relocated to the front and other custom components but I suspect some of the Pantera vendors have conversion kits to do the above for OE configurations. However, it still requires all the associated labor.

Once you get everything buttoned up, the system needs to be pulled down to vacuum for a period of time then charged with refrigerant and lubricant. This requires specialized equipment that sometimes can be rented or merely bring your completed car to a qualified service center.

If you do all that is described above, you’d likely have a system that would work on demand for a number of seasons. Without the attention to detail, it may require recharging multiple times per year. It just depends on how leak tight of a system you can achieve.

If you are still interested in tackling the task, I can list sources.

Best,
K


Brilliant reply, that is certainly the rumour killer, it is a far bigger job than I was led to believe, you have to be right about my original hoses too they look good but only from the outside! Having spent 12 months almost just getting the car roadworthy, I am going to get a good summer use out of it before trying to improve the paintwork and complete a suspension overhaul.

The A/C can now go on the backburner until a later date due to the cost and time involved.
Thank you again for such comprehensive advice,
great info from this forum again.( also your cars are stunning) Pete
J jffrMember
quote:
Originally posted by sjdennis:
Has anyone tried Red Tek 12a in the stock system in place of R-12?

http://redtek.com/English/product.asp?ID=18

Seams to not require much retrofitting.
"Similar volumetric refrigerating effects to R-12"

I don't know much about HVAC systems but would interested to here what those that do think about this?

Dennis


I have been using Red Tek 12a in two of my vehicles for many years and it works very well. One vehicle has an original R-12 system and it was a virtual drop in replacement. I just added the Red Tek to the system when it was almost empty and that was it. My Pantera also has Red Tek in it and it also works great. The Pantera does have a front mounted condenser with all the correct R134 hoses and expansion valve, but Red Tek is a drop in replacement for it also. What is nice about the Red Tek is that it runs at much less pressure than R134 does. I know there has been a great deal of discussion about placing a condenser in front of the radiator in a Pantera, but I don't have an over heating problem thanks to many cooling system modifications and a Fontana aluminum block and heads. That said, I don't intend to high jack this thread. I also live in southeastern Arizona, which makes having air conditioning in any vehicle almost a necessity.
Last edited by jffr

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