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Discussion Starter · #1 ·
Need the honest scoop (maybe someone's BS'ing me)
The AC hoses on my 81 are original and while the system is down I'm wanting to change them out... unless It's not necessary.
* on a YouTube video for the R12 to 134a conversion I hear > > > "the hoses for for later model vehicles using factory installed 134r are sleeved inside so the smaller 134r molecules won't leak out"

I called a Corvette specific parts retailer (no names mentioned) and I was told "our hoses for Corvettes are compatible with both R12 and 134r". (I'm thinking maybe his hoses are just everyday AC hoses and what I may already have but 'his' are just 'new' and from China like everyone else's parts, that maybe even Pep Boys or Napa, Rock Auto etc. sells)

Question > > > are there actual replacement hoses for my 81 that are sleeved (or redesigned) to better hold-in the 134a or... is that a line of bs?

I always appreciate your words of wisdom!
 

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From what I’ve been told 134a works at a higher pressure than R12 does. Other than than don’t have much more information than that. R12 is almost impossible to find and if you do it’s like $$$$$ a pound to buy. Most do a conversation what that in tail’s I do not not know.
 

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The hose used with R134a is called "barrier" hose. There is a visible "sleeve" you can see in the photo below. It has an SAE spec# J3062-134a. If you google that spec you can see that the hose is designed to control the "permeation" of the refrigeration. Permeation is the molecular penetration of gas or fluid through the membrane of a solid. I'm sure you've had the experience of discarding some empty oil cans in a plastic garbage bag, with no tears or holes, and the next morning you have oil on the floor that came through the bag. That's permeation.

I'm sure some have gotten away with the R12 hoses on R134a or R1234, but if you need new hoses why take a chance? There are hundreds of ends that can be crimped onto barrier hose that will be very similar to the ends on your stock system. I also recall that exact replacements with barrier hose are available if you want to keep an absolutely stock appearance. But it wouldn't be any strain for a good AC shop to make up some hoses that would be very similar to what you have.

Your existing condenser and evaporator will work with a conversion to R134a although replacement condensers are available that will be a little more efficient. Might be a good time to consider replacing the R4 compressor with a Sanden or equivalent. You don't have to, but the R4 is known to be a troublemaker. Many have made them work just fine, but there are better designs available today. I attached a picture of a friend's Firebird with the Sanden conversion from an R4 so you can get an idea of how it fits. It was painless and works great here in the flatlands of Oklahoma where summer heat/humidity is often brutal. His condenser and evaporator are stock.

Hope this helps!
Bicycle part Gas Audio equipment Carbon Auto part


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Motor vehicle Car Vehicle Automotive design Automotive fuel system
 

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DC PIT CREW BOSS
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I your Vette still charged with R12 or has it been converted sone time in the past?R134 molecules are smaller and it requires a different lubricant. If your system is a first time 134 user the system must be completely evacuated and the compressor cleaned and re-lubricated with the correct oil. If it were me I'd just replace the compressor.
Just make sure whoever redoes the system change knows what they are doing
 
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Discussion Starter · #5 ·
I your Vette still charged with R12 or has it been converted sone time in the past?R134 molecules are smaller and it requires a different lubricant. If your system is a first time 134 user the system must be completely evacuated and the compressor cleaned and re-lubricated with the correct oil. If it were me I'd just replace the compressor.
Just make sure whoever redoes the system change knows what they are doing
Thanks for the info; back in 2014 the system was moved over from R12 to 134a and it 'was' impressively cold.
Even prior to 2014 the same shop did my old F250 Diesel that was also R12 to 134a and that 'still' works very well.
Heading to a 'new' shop for the Vette and I would like to swap out the original 81 hoses, but to one that is for the 134a.
 

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Discussion Starter · #6 ·
The hose used with R134a is called "barrier" hose. There is a visible "sleeve" you can see in the photo below. It has an SAE spec# J3062-134a. If you google that spec you can see that the hose is designed to control the "permeation" of the refrigeration. Permeation is the molecular penetration of gas or fluid through the membrane of a solid. I'm sure you've had the experience of discarding some empty oil cans in a plastic garbage bag, with no tears or holes, and the next morning you have oil on the floor that came through the bag. That's permeation.

I'm sure some have gotten away with the R12 hoses on R134a or R1234, but if you need new hoses why take a chance? There are hundreds of ends that can be crimped onto barrier hose that will be very similar to the ends on your stock system. I also recall that exact replacements with barrier hose are available if you want to keep an absolutely stock appearance. But it wouldn't be any strain for a good AC shop to make up some hoses that would be very similar to what you have.

Your existing condenser and evaporator will work with a conversion to R134a although replacement condensers are available that will be a little more efficient. Might be a good time to consider replacing the R4 compressor with a Sanden or equivalent. You don't have to, but the R4 is known to be a troublemaker. Many have made them work just fine, but there are better designs available today. I attached a picture of a friend's Firebird with the Sanden conversion from an R4 so you can get an idea of how it fits. It was painless and works great here in the flatlands of Oklahoma where summer heat/humidity is often brutal. His condenser and evaporator are stock.

Hope this helps!
View attachment 105407

View attachment 105408

View attachment 105409
Once again a wealth of information and with 'pictures!
#1 I would prefer to acquire the "barrier" hoses that are pre made-up for a simple off/on replacement. That being said, I 'question' if what an over the counter parts retailer 'is' the barrier type hose replacements.
One Vette parts retailer just said to me "our hoses are compatible with both R12 or 134a". He never mentioned they had a "barrier" inner lining... and it could just be what I already have.

#2 looking at the compressor you posted; it is 'deeper' vs my OE type radial compressor and using the unit you posted, I would not be able to reuse the O.E. plastic cool air intake runners... I would like to keep those in operation.
BTW... I did respond to your prior thread about the steering box etc.
 

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Once again a wealth of information and with 'pictures!
#1 I would prefer to acquire the "barrier" hoses that are pre made-up for a simple off/on replacement. That being said, I 'question' if what an over the counter parts retailer 'is' the barrier type hose replacements.
One Vette parts retailer just said to me "our hoses are compatible with both R12 or 134a". He never mentioned they had a "barrier" inner lining... and it could just be what I already have.

#2 looking at the compressor you posted; it is 'deeper' vs my OE type radial compressor and using the unit you posted, I would not be able to reuse the O.E. plastic cool air intake runners... I would like to keep those in operation.
BTW... I did respond to your prior thread about the steering box etc.
As far as the hoses are concerned, look for the SAE J3062-134a stamped on the hose. If it's not there, don't buy it. I can't speak to the actual fitment of the Sanden compressor retrofitted to the 81 but I know I've seen them. It's probably all in the brackets, I know I've seen several of them on the 80-82 Corvettes. I would bet on Vintage Air having a setup for it. The Sanden is way smaller than the R4 so there should be a way to make it fit, but I have never actually tried it myself. I did use the Vintage Air Frontrunner setup on my 81 LS-3 swap and it seems like I saw a variety of setups for a stock R4/Sanden swap. Based on what I've seen, I would definitely try to find a way to make the Sanden work if you go to the trouble and expense of a R134a conversion. My 2c anyway!
 

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As far as the hoses are concerned, look for the SAE J3062-134a stamped on the hose. If it's not there, don't buy it. I can't speak to the actual fitment of the Sanden compressor retrofitted to the 81 but I know I've seen them. It's probably all in the brackets, I know I've seen several of them on the 80-82 Corvettes. I would bet on Vintage Air having a setup for it. The Sanden is way smaller than the R4 so there should be a way to make it fit, but I have never actually tried it myself. I did use the Vintage Air Frontrunner setup on my 81 LS-3 swap and it seems like I saw a variety of setups for a stock R4/Sanden swap. Based on what I've seen, I would definitely try to find a way to make the Sanden work if you go to the trouble and expense of a R134a conversion. My 2c anyway!
Oh, forgot this. The Torch is spot on... It is ESSENTIAL that the system be thoroughly flushed of all lubricant and everything else when converting to R134a. The system must be squeaky clean on the inside. I don't know that it's even possible to thoroughly flush a R4 compressor, so that right there might be the deciding factor on changing out the compressor.
 

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Need the honest scoop (maybe someone's BS'ing me)
The AC hoses on my 81 are original and while the system is down I'm wanting to change them out... unless It's not necessary.
* on a YouTube video for the R12 to 134a conversion I hear > > > "the hoses for for later model vehicles using factory installed 134r are sleeved inside so the smaller 134r molecules won't leak out"

I called a Corvette specific parts retailer (no names mentioned) and I was told "our hoses for Corvettes are compatible with both R12 and 134r". (I'm thinking maybe his hoses are just everyday AC hoses and what I may already have but 'his' are just 'new' and from China like everyone else's parts, that maybe even Pep Boys or Napa, Rock Auto etc. sells)

Question > > > are there actual replacement hoses for my 81 that are sleeved (or redesigned) to better hold-in the 134a or... is that a line of bs?

I always appreciate your words of wisdom!
Because of the age , I would go to a hose building shop , Use your original metal ends & have new rubber = new hoses & much cheaper than trying to find original lines
 

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I’ve only done two conversions, but they both worked for years and were still going strong when I sold the cars. I did them when my R12 compressors went bad, so I replaced the compressors, the hoses, and the filters. I also put in new orifice tubes, as the R134 ones were sized to increase pressure, as I recall. Also, I used ester oil, as it was impossible to totally clear the system of the oil used with R12 and the R134 would turn it corrosive (chlorine, I think?). But ester oil would blend it all into a safe lubricant for R134. As I mentioned, I did buy new hoses, so they had the proper connections and were built for R134.

Good luck!
 

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Discussion Starter · #11 ·
Because of the age , I would go to a hose building shop , Use your original metal ends & have new rubber = new hoses & much cheaper than trying to find original lines
The only "hose" shop I know of in my area is Delri Industrial Supply. Many years ago we used them to rebuild Hydraulic rams and high pressure hoses for heavy equipment (Dozers etc).
But visiting their website and to my surprise "air conditioning" is listed. I'll be curious to see 'if' they can do as you suggested.
 

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The only "hose" shop I know of in my area is Delri Industrial Supply. Many years ago we used them to rebuild Hydraulic rams and high pressure hoses for heavy equipment (Dozers etc).
But visiting their website and to my surprise "air conditioning" is listed. I'll be curious to see 'if' they can do as you suggested.
Mine work great , the shop even cleaned my metal parts & kinda tricky metal ends with 2 metal hoses going to a/c compressoir. Actually saved me the $300 range
 

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Great to read some knowledge here about the hose barrier. We will do the AC maintenance soon after installing the new tires from 4Wheelonline, and it might be a great time to get better hoses.
 

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You could also just buy the hose, one of these, and then get some universal ends and make your own 2 hoses for the compressor..

Amazon.com: VPA 34108-VUG OEM Compressor Adapter Block Kit GM A6/R4 Early-Style Compressor A : Automotive

You know you get some fittings with the bends you like..

RV SANDEN SD508 709 SELTEC RETROFIT R134 a FLARE COMPRESSOR FITTINGS PORT (coolairparts.com)

or these..

SANDEN SD508 709 TAMA SELTEC COMPRESSOR FITTINGS W/Port | eBay

or if you look you can get them in straight. And with or without the service ports. Then you get the fittings for the condenser and for the accumulator and build your own hoses from scratch. And for less money. And without tool marks or grinds from the cutting wheel that removed the old hoses. If you wanted to do this yourself you would also invest in a good handheld hydraulic crimping tool like this guy right here..

Mastercool Inc., Manufacturer of Air Conditioning, Refrigeration, Service Tools and Equipment
 

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If they are the original hoses and still in good shape, then the inside of the hoses are probably "coated" from the previous use. Permeation may not be a big issue. Double check all the hoses for any cracking, etc. that would allow for leaks.
 
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