73 ac

[texas charger 73]

I have a 73 charger smll block. I would like to get the AC done. I have the compressor and that's about all. Can I buy the lines for the old r12 compressor new or do I need to find used and just buy a new condenser, dryer and expansion valve?  Or should I just find a full replacement system?

[b5blue]

"Classic Auto Air" can help repair. 

[Pete in NH]

Hi,

I've never seen reproduction A/C lines offered, maybe someone else has. If you can find a set of used original lines, you can get them rebuilt. I used a company called"Cold Hose" down in Florida and the did a great job for only $30 per line  The RV-2 has unique fittings so I doubt anyone will ever reproduce them. All things considered, a modern replacement system might be your best option unless you want to keep things original. The old RV-2's are nearly indestructible if cared for but they are heavy and a bit noisy compared to new compressors.

[texas charger 73]

I just have to find who will install a system to work with factory components.  Old air products want to replace with an under dash system. I have vintage air don't offer nothing for 73 charger. I might have to see about classic air auto. Is there any others I'm missing?

[ODZKing]

I will add my two cents here. I'll try to make a long story short. I have a 73 that had factory air but was missing most of the components under the hood. My thought was, no problem I'll just replace all of the under hood components and go with the new setup, I ended up going with classic Auto air.
It works okay except for the fact that it doesn't really cool as well as other units. And again it's okay for around town but on long trips it constantly freezes up so you can only use it for maybe 15 to 30 minutes at a time. I've taken it to numerous places to try to see if the situation can be resolved, and all I understand is that it's not the original system. So since what I have done is located all the original parts used and I'm going to restore the system back to its original state. The compressor and lines I know can be updated to the new style and that's what I intend to do.
So in a nutshell, keep your original stuff for find the original parts, restore it the way it was and it'll work as designed, or get the new stuff and be disappointed and fight with it until you decide to do something else.
Again, my two cents.

[Pete in NH]

I don't know anything about the Classic Air system, so maybe you can fill me in. It should not freeze up in 15 to 20 minutes. Does Classic Air cycle the compressor and if so do they do it based on evaporator temperature? That is how you would keep it from freezing up. i don't know anything about their systems cooling capacity, so I can't say if it's undersized. In our bigger cars depending on things like a black vinyl roof , interior color etc. it can take a 30,000 BTU system capacity to cool the car. If you think in terms of house A/C that's a big system. Anyway, the system should not freeze up and a proper temperature probe switch in the evaporator case cooling fins should solve that issue and have it cycle the compressor. total cooling capacity is another issue.

[ODZKing]

I don't know anything about the Classic Air system, so maybe you can fill me in. It should not freeze up in 15 to 20 minutes. Does Classic Air cycle the compressor and if so do they do it based on evaporator temperature? That is how you would keep it from freezing up. i don't know anything about their systems cooling capacity, so I can't say if it's undersized. In our bigger cars depending on things like a black vinyl roof , interior color etc. it can take a 30,000 BTU system capacity to cool the car. If you think in terms of house A/C that's a big system. Anyway, the system should not freeze up and a proper temperature probe switch in the evaporator case cooling fins should solve that issue and have it cycle the compressor. total cooling capacity is another issue.

Well there is the issue. They send a cheap thermostat which (they say) is designed to wrap around the outgoing tube and mounted on the firewall. Obviously that doesn't work. On some advise from another fellow who had the same problem, I moved it to the other side of the firewall, it helped some but still freezes.
After taking it to various places my understanding was, yes it should be on the heater box with the evaporator. Too late for that now, I'm not pulling the dash to do that. Hence why I am going back to original setup (eventually). This year doesn't matter as the cars are going nowhere anyway.

[Nacho-RT74]

new condensers, dryers and expansion valves are available in stock form. Condensers are in fact available in aluminium for better performance.

Dryers and expansion valves are available for either R12 or R134. Is just about request the right PN. They Phisically are the same part just ready for one or the other gas. Rockauto has them and I can give you the PNs. Dunno if they have the condensers but I got mine from ebay on $200 or so rate when they barelly where released available. Exact piece to the original iron one.

Lines... sorry, you'll need to get them used, and if is the case get replaced the hoses. You can either get from SB or BB and just make the hoses as the needed lenght. The important is they came out from a 73 and later B body.

B body A/C system regulates the temperature "ciclying" the pressure by the EPR valve, so the compressor is allways working as far there is gas on the system. A bodies get a thermostatic switch to cycle the temp turning on and off the compressor.

If you upgrade from R12 to R134 will need to use the correct O rings, oil, and is adviced to use a thermostatic switch to cycle on and off the compressor, since the R134 works at a diff pressure and the EPR is not adjustable, needing to be removed. If you keep using R12, you won't have to make nothing.

Hoses needs to be replaced if they are damaged for the correct gas. R134 gas molecules are smaller and they leak through the hoses used for R12. However if you find an original SB 73 and lates lines setup and hoses are in good conditions, they should be seasoned enough to hold the R134 gas. I run my stock hoses with R134 without problem for loooong time and the gas hold nicelly.

That's all the info I have. I upgraded to R134 but MY A/C system has worked with and without the EPR valve nicelly, but never installed the thermostatic switch.

All the pics about this upgrade and A/C shops use to attach the thermostatic switch sensor lines to the lines leaving the firewall, HOWEVER A bodies got the sensor installed into the A/C box evaporator core. I think that would be the real spot for it, because will sense by the actual temp into the box, which is the one being blowed out throught the vents, and the one you really care

[John_Kunkel]

The original hoses were more complex than need be IMHO, all the mufflers and intricate bends in the hoses are hard to duplicate. All the hoses can be replaced with modern barrier hose, the crimp-on hose fittings will match up to most of the system. In some cases the rear/front compressor fittings can be swapped (use two fronts or two rears) to make them compatible with common hose fittings.

To avoid the cost of custom hoses, you can purchase a good crimper and do it yourself. The crimper will pay for itself.

https://www.amazon.com/Mastercool-71550-Black-Manual-Crimper/dp/B000WBQ4U2

FWIW, I don't consider R-134 to be an "upgrade", stay with R-12 and the system will operate as intended without need to change the expansion valve or add a clutch cycling switch.

[Pete in NH]

ODZKing- If Classic Air are supposed to be A/C professionals I would doubt how knowledgeable they are telling you to install the cycling switch that way. If you are still using the original heater/evaporator case you might try drilling a small hole around the heater blower motor resistor area , removing the resistor assembly and working through that hole to sneak the sensing probe along the evaporator core. That would have to work better than what they suggest. I wouldn't want to pull that whole evaporator assembly out either. What they are suggesting is like trying to take your body temperature by placing the thermometer between your toes instead of under your tongue and calling it close enough.

To the original poster- use the biggest parallel flow condenser you can fit in front of you radiator. Use all the factory pieces in terms of fan clutch, fan, radiator shroud and any hood to radiator yoke seal strips. Air flow through the condenser is important. The original condenser was a serpentine flow unit, upgrade it to parallel flow especially for R-134A, The original RV-2 used on V-8's was around 10.5 cubic inches displacement. If you use a Sanden type you want the same size displacement. All recent receiver/dryers are R-12 or R-134A compatible. Those EPR valves used in the RV-2 are quickly becoming unobtanium, think $100+ if you can find them, that's why a cycling switch system makes more sense today. If you want to use your old RV-2 compressor a new shaft seal and gaskets would be good things to do. Also, you want to clean out the old mineral oil if you are going to R-134A. I like to use an Ester based oil which is compatible with either  R-12 or R-134A.

John- your right R-134a is not an upgrade. It's just what's available and serviced by everyone today. It's almost impossible to find a shop that will touch an R-12 system today.

[b5blue]

I have Classic in my 70. I use my car quite a bit, rain or shine in nasty hot/wet Florida and A/C is fine. Any hydraulics shop should make/fix lines? 

[Bronzedodge]

Good advice from Pete in NH above.    Keep your AC heater box and controls under the dash and replace all under hood components.   Reverse flush your evaporator, repeatedly.    Be careful with aluminum threads on the evap, use oil.  The factory stuff in the dash is superior to the aftermarket, the Sanded type compressor draws less HP than the RV2.   A really good kit would regulate the evap pressure to maintain a 38* evaporator temperature, but I haven't seen one yet. 

[texas charger 73]

ODZKing- If Classic Air are supposed to be A/C professionals I would doubt how knowledgeable they are telling you to install the cycling switch that way. If you are still using the original heater/evaporator case you might try drilling a small hole around the heater blower motor resistor area , removing the resistor assembly and working through that hole to sneak the sensing probe along the evaporator core. That would have to work better than what they suggest. I wouldn't want to pull that whole evaporator assembly out either. What they are suggesting is like trying to take your body temperature by placing the thermometer between your toes instead of under your tongue and calling it close enough.

To the original poster- use the biggest parallel flow condenser you can fit in front of you radiator. Use all the factory pieces in terms of fan clutch, fan, radiator shroud and any hood to radiator yoke seal strips. Air flow through the condenser is important. The original condenser was a serpentine flow unit, upgrade it to parallel flow especially for R-134A, The original RV-2 used on V-8's was around 10.5 cubic inches displacement. If you use a Sanden type you want the same size displacement. All recent receiver/dryers are R-12 or R-134A compatible. Those EPR valves used in the RV-2 are quickly becoming unobtanium, think $100+ if you can find them, that's why a cycling switch system makes more sense today. If you want to use your old RV-2 compressor a new shaft seal and gaskets would be good things to do. Also, you want to clean out the old mineral oil if you are going to R-134A. I like to use an Ester based oil which is compatible with either  R-12 or R-134A.

John- your right R-134a is not an upgrade. It's just what's available and serviced by everyone today. It's almost impossible to find a shop that will touch an R-12 system today.



i just want to have ac.. its hot in Texas and on super hot days its not enjoyable at all... if i can keep all under dash stuff original and upgrade to a lighter compressor and components  under hood that would be fantastic as the old ac unit weighs like a million pounds. i dont know alot about ac so im probably gonna have to find some step by step directions and make sure i can get all the proper parts

[texas charger 73]

i just want to have ac.. its hot in Texas and on super hot days its not enjoyable at all... if i can keep all under dash stuff original and upgrade to a lighter compressor and components  under hood that would be fantastic as the old ac unit weighs like a million pounds. i dont know alot about ac so im probably gonna have to find some step by step directions and make sure i can get all the proper parts. all i have left under hood is the compressor, but under dash parts are all still there

[ODZKing]

ODZKing- If Classic Air are supposed to be A/C professionals I would doubt how knowledgeable they are telling you to install the cycling switch that way. If you are still using the original heater/evaporator case you might try drilling a small hole around the heater blower motor resistor area , removing the resistor assembly and working through that hole to sneak the sensing probe along the evaporator core. That would have to work better than what they suggest. I wouldn't want to pull that whole evaporator assembly out either. What they are suggesting is like trying to take your body temperature by placing the thermometer between your toes instead of under your tongue and calling it close enough.

Oh YES they did. They had NO instructions for 71-74 B bodys and they originally sent me 68-70 instructions which obviously did not match. So I called and they sent me instructions for 70-74 E body.
Following the instructions I sent them THIS picture and asked specially if it was correct. His reply:
The T-stat temp sensing tube should be wrapped around the low side fitting at the same place you clamped the expansion valve temp sensing bulb. It does not have to be completely would but you want metal to meta contact on the probe before insulating.  Now to clarify that is a switch to prevent the system from icing up. The only reason that would cause a loss of cooling is if the coil is freezing up. If it is freezing up you would lose air flow as well due to the coil becoming a block of ice.

[Pete in NH]

ODZKing- I have no doubt they told you to do it that way. It's just, as you have found out, not going to really keep the evaporator from freezing up. I think they were trying to find an easy way out. You need to keep the evaporator  core slightly above freezing, like around 38 degrees or so, otherwise the water condensate produced will start to freeze. What better place to know what the evaporator temperature is than at the evaporator, not the metal line down the road.

Texas Charger- Having an A/C shop do the work you're looking for is going to be expensive and many shops don't want to mess around with old cars and non-standard installations . They can make more money with less hassle working on modern cars. There is no magic in automotive A/C and if you can do other mechanical work on your car you can do the A/C stuff. Mounting the compressor, evaporator, lines and cooling system components like the fan and shroud is pretty much straight mechanical work. Do you have the original factory shop manual for your car? You will find lots of good information in it about A/C systems. I and others can help you with questions and finding the right parts. My car is a 71 big block with the original RV-2 so I can't help you with mounting brackets for a Sanden type compressor on a small block but, I'm sure others can, i know there are mounting brackets available. i can help you with the right compressor, condenser and expansion valve. finding a 73 B body small block with A/C parts as a donor would be very helpful.

[ODZKing]

ODZKing- If Classic Air are supposed to be A/C professionals I would doubt how knowledgeable they are telling you to install the cycling switch that way.  

My point was they did
It was Ron Mineo - Classic Auto Air
I kept the email

[texas charger 73]

ODZKing- If Classic Air are supposed to be A/C professionals I would doubt how knowledgeable they are telling you to install the cycling switch that way. If you are still using the original heater/evaporator case you might try drilling a small hole around the heater blower motor resistor area , removing the resistor assembly and working through that hole to sneak the sensing probe along the evaporator core. That would have to work better than what they suggest. I wouldn't want to pull that whole evaporator assembly out either. What they are suggesting is like trying to take your body temperature by placing the thermometer between your toes instead of under your tongue and calling it close enough.

Oh YES they did. They had NO instructions for 71-74 B bodys and they originally sent me 68-70 instructions which obviously did not match. So I called and they sent me instructions for 70-74 E body.
Following the instructions I sent them THIS picture and asked specially if it was correct. His reply:
The T-stat temp sensing tube should be wrapped around the low side fitting at the same place you clamped the expansion valve temp sensing bulb. It does not have to be completely would but you want metal to meta contact on the probe before insulating.  Now to clarify that is a switch to prevent the system from icing up. The only reason that would cause a loss of cooling is if the coil is freezing up. If it is freezing up you would lose air flow as well due to the coil becoming a block of ice.

what system did you get because the only charger System they offer is for 66-70.. nothing 3rd gen B body..

[texas charger 73]

Texas Charger- Having an A/C shop do the work you're looking for is going to be expensive and many shops don't want to mess around with old cars and non-standard installations . They can make more money with less hassle working on modern cars. There is no magic in automotive A/C and if you can do other mechanical work on your car you can do the A/C stuff. Mounting the compressor, evaporator, lines and cooling system components like the fan and shroud is pretty much straight mechanical work. Do you have the original factory shop manual for your car? You will find lots of good information in it about A/C systems. I and others can help you with questions and finding the right parts. My car is a 71 big block with the original RV-2 so I can't help you with mounting brackets for a Sanden type compressor on a small block but, I'm sure others can, i know there are mounting brackets available. i can help you with the right compressor, condenser and expansion valve. finding a 73 B body small block with A/C parts as a donor would be very helpful.
[/quote]

Pete Yes i have the 73 shop manual... i guess i need to start with what parts i need to find for under hood. so far i got a compressor and thats all... im assuming the lines will be the hardest to obtain... should i leave it r-12 or is it pretty easy to convert to r-134?  i guess i also need to open up shop manual and check out the ac section.. im gonna be pulling heater box to and replacing core as it was leaking

[texas charger 73]

i did just find this


https://www.originalair.com/73-74-b-body-mopar-engine-compartment-upgrade-kit-318-340-360-wstock-parallel-flow-condenser-r134a-stage-2-small-block

[b5blue]

Yea that's what I mean. You can send Classic your dash unit for rebuild. (The Tampa store has been the go to guys for over 30 years around here.)
https://www.originalair.com/

[ODZKing]

Texas73, to answer your question they do not have a package for 73. However I did not need an entire package all I needed was the underhood kit because my car originally had factory air. They cut the hoses to fit and the compressors are basically the same as well as the condenser. Or so they told me.

[Pete in NH]

ODZKing- If Classic Air are supposed to be A/C professionals I would doubt how knowledgeable they are telling you to install the cycling switch that way.  

My point was they did
It was Ron Mineo - Classic Auto Air
I kept the email

I think you may have ms-read my original wording or I wasn't as clear as i might have been. I am not saying they didn't tell you to install the cycling switch as they did. I'm saying that I'm questioning how well they understand what is required for the system to work correctly. The proof that they got it wrong was that your system is freezing up inspite of how you try to adjust the sensing location on the evaporator inlet line. I'm not questioning you-I'm questioning Classic Air.

To Texas Charger- If you go with the Classic air system and have the evaporator out of the car just install the cycling switch probe correctly in the evaporator case and you will not have the freeze up problem.

[ODZKing]

I think you may have ms-read my original wording or I wasn't as clear as i might have been. I am not saying they didn't tell you to install the cycling switch as they did. I'm saying that I'm questioning how well they understand what is required for the system to work correctly. The proof that they got it wrong was that your system is freezing up inspite of how you try to adjust the sensing location on the evaporator inlet line. I'm not questioning you-I'm questioning Classic Air.

To Texas Charger- If you go with the Classic air system and have the evaporator out of the car just install the cycling switch probe correctly in the evaporator case and you will not have the freeze up problem.

No disrespect intended, and yes your being kind when you say you doubt how knowledgeable they are. The sad thing is I HAD the heater box rebuilt and had I known before it went back  in the car we wouldn't even be having this conversation. So yes, you are correct in assuming they are idiots. I guess they assume you know what you're doing but A/C is not something everyone knows. It's not like replacing a headlamp.
So TexasCharger ... yes ask lots of questions here and install it correctly or pay the extra buck and have it professionally installed by someone who knows what they're doing. It would be worth every penny to have A/C that works IMHO.

[Nacho-RT74]

The basics of the A/C are pretty much straight up an easy to understand thinking is a temperature interchange system based on gases low and high pressure system, but not the details about how it actually performs, which is what actually gets wrong

[texas charger 73]

when i get to a point where i can start fixing mine i will be asking tons of questions.. first thing i will be doing is pulling ac/ heat box to rebuild it and put in a new heater core... where is best place to get a heater core... i know Detroit muscle technologies sells a good box rebuild kit...  also what is this switch your saying i need to add to the box while i got it out

[Nacho-RT74]

I'd say check the cores first... Maybe doesn't need to be rebuilt or replaced.

[Pete in NH]

The original factory evaporator core is far superior to any after market part. If it is in good condition flush it out and re-use it. On heater cores, all the after market stuff is now produced off shore in the far east. The quality of these parts varies greatly and are no where near original quality. If you need to replace the heater core because of leaks you'll have to go with an after market part but its a crap shot on quality these days.

[texas charger 73]

i got a guy that has a good original core.. i may go with it.. he only wants $65 for it

[texas charger 73]

I'd say check the cores first... Maybe doesn't nedd to be rebuilt or replaced.

the core in it was leaking.. i bypassed it

[John_Kunkel]

You might also look for local radiator shops that can re-core the heater core. A used one that doesn't leak now might have a short life when put back in service.

[texas charger 73]

You might also look for local radiator shops that can re-core the heater core. A used one that doesn't leak now might have a short life when put back in service.

i can pull my heater box and still drive my car around cant i?

[Mike DC]

            
Aftermarket (in-dash) HVAC systems are just too small.  The companies are trying to make a few boxes that fit many different old car models (to keep the costs down) and they have to compromise on the size.  Modern freon also runs weaker than the old stuff which makes it worse.

Look at a modern car's dashboard.  It's absolutely stuffed to the gills with the HVAC system.  That's what it takes to deliver the cooling we are used to.  


Aftermarket window tinting can be a real asset for cooling now.  The new stuff targets certain wavelengths better.  Like, the glass only looks 20% darkened to your eyes but it's blocking 40% of the heat/UV rays.  Some OEM cars are using it lately.  

[b5blue]

You might also look for local radiator shops that can re-core the heater core. A used one that doesn't leak now might have a short life when put back in service.

i can pull my heater box and still drive my car around cant i?

Yea just cap or run one hose to both heater feed nipples.

[John_Kunkel]

i can pull my heater box and still drive my car around cant i?

I would cover the firewall holes to prevent noxious fumes from entering the cabin.