R-12 auto A/C tech in chit chat

[Lee]

I had good luck with Red Tek in dad's John Deere 2755. Red Tek is propane based R12 replacement. I bought it from Amazon, but couldn't find the actual refrigerant there now, just the accessories.

Here's a random Google result:

REDTEK A/C Refrigerant 6 oz cans & Installation Hose w/Gauge - 3 Cans

RED TEK A/C Refrigerant can be used in all R134a applications, including pre-1994 automobiles that have complied with the USEPA Snap Law. Operation: RED TEK A/C Refrigerant possesses similar volumetric refrigerating effects to R134a refrigerants. Operates at lower head pressures and offers...

www.redtekstore.com

 

[plym49.2]

I had good luck with Red Tek in dad's John Deere 2755. Red Tek is propane based R12 replacement. I bought it from Amazon, but couldn't find the actual refrigerant there now, just the accessories.

Here's a random Google result:

REDTEK A/C Refrigerant 6 oz cans & Installation Hose w/Gauge - 3 Cans

RED TEK A/C Refrigerant can be used in all R134a applications, including pre-1994 automobiles that have complied with the USEPA Snap Law. Operation: RED TEK A/C Refrigerant possesses similar volumetric refrigerating effects to R134a refrigerants. Operates at lower head pressures and offers...

www.redtekstore.com

So with this stuff or something like it there is no reason to change the 710 used in the R12 system? No need to add any, either?

 

[plym49.2]

at work we dump in 134 with PAG oil
don't worry about the left over mineral oil from the r12
it works fine

what I do on my own shit is to break the vacuum with propane, then charge with 134, the propane carries the mineral oil through the system
it also works fine, just less... approved by the powers

what

install pag oil into dryer (iirc those old GM ones were one of the very few that call for the 150 viscosity, but 100 or 46 will probably be just fine), attach all the hoses and shit
vacuum
break vacuum with propane
charge with 134 until it makes enough cold with max blower

r12 fittings are just 1/4" flare, you can figure out the propane tank to that if you aren't dumb
don't bother with disposable cans or butane stuff
the butane would work better for carrying the oil but it is going to be harder to adapt so...

I replace the one in my dad's '89 blazer every 4-5 years it starts to leak.

I did the conversion on a '89 extra cab c3500 new dryer, pump and orfice tube flushed everything else add pag oil and r134, it works great. I used a scale to measure the amount of r134 that I used.

Another tip: Replace the condenser with one from a 1994 model. Those are slightly larger to account for the additional cooling needs of the 134a. Make sure you add 10% less R134 than the system calls for, as the R12 weighs 10% more.

Oh, yeah... the pressure switches are interchangeable as well, so grab those from the 94, too.

1. Replace the o-rings and keep it R-12. But if leaks persist I will run out of R-12. Is there R-12 leak dye any more?
2. R-134a conversion. But what about the R-12 lube and the fact that R-12 system pressures are not right for R-134a? What other stuff would I need to do?
3. Bacon.

1. I have the o rings sitting in my toolbox. There’s a ton of adaptor o rings depending on exactly what updated compressor you have (there were several updates). A pic of the line separated from the comp so I/we can see what else are dealing with would be best. A lot of the adaptor o rings/seal never worked exactly right, but worked.
2. I would do the conversion though. I was at the dealer when this all came about, so I’m familiar with it. The 2 oils are but are not compatible. Basically, GM recommended replacing the accumulator (trying to remember if the orfice needed replacement too, I don’t think so though) and flushing out as much oil as possible. You can flush the lines with denatured alcohol and compressed air. If you feel frogs, pull the compressor and try to dump any oil that’s in there too. Then you add in the r134a oil. There was a big mathematical equation GM had for the conversion for the amount of Freon needed. Basically, it was .5# less
3. mmmmmmmmmbacon. Aaaaahhhhhh

I would just vacuum it and charge it with 134 it from cans. You can get a can with oil and dye in it. Then use a blacklight to find the leak When it leaks out.

Many shops have a big AC O ring assort box for matching up odd stuff. You can usually look up the dimensions online but sometimes it’s compare and guess. If you get dimensions I’ll look at my O rings.

The low pressure cutout switch. When you convert to R134 back it off about a turn to 1.5 turns. So the cutout is down around 10 psi. It helps keep the pressures down and gets colder. .

But yeah convert. Won't be long and R134 will be the new R12 with the 1234yf coming.

Right now you can buy 30lb R134 for $80. Everyone should grab a few.

Air powered vac pump from harbor freight is fine. Just leave it on there as long as your compressor will allow.

Old oil is fine.

Ester oil & 134 low side conversion fitting is my go to.
Fix what's leaking, spin on low side fitting, pull and hold vac, add some ester oil & charge to 80% of the original capacity. I've had really good luck doing it this way. Probably do 3 or so cars a year

Oy vey. So many options from just top it off with 134 and DGAF to flush and replace and everything.

I've a mind to crack a line and flush with 134 or whatever. A few extra cans is less expensive than a vacuum pump.

Help me navigate the varied (and all of it good) suggestions, please.

 

[M92PV4U]

I used something like this Amazon.com to flush and just followed instructions.

 

[plym49.2]

unless it's hammered dog shit

I just assumed you cared about it and it was cherry. But maybe you're one of those guys that wants his money's worthlong bed extra cab 4.3 5speed 4 mismatched 245s, top post yard sale battery with auto zone adaptors, bed cut for the fuel pump, half inch door sag....

Fucking run 134, propane, butane, whatever

Here's my long bed extra cab 4.3 5speed 4 mismatched 245s, top post yard sale battery with auto zone adaptors, bed cut for the fuel pump, half inch door sag veehickle:

 

[crisbee1]

I did this on my 92' . The pancake compressors suck.

Absolutely brand new Sanden 508 compressor from Vintage Air, there are options for line clocking. The Sanden should come with the correct amount of oil in it.

Vintage air sells an adapter brackets for the Sanden, $80.

New dryer, do not uncap till you are ready to hook up a line.

New orifice tube, IIRC r12 and r134 use a different size screen.

New condenser just because.

I tapped a blow gun for a -4 AN to pipe union. connect to service port to blow out.

I use a/c flush, some use brakekleen.

You gotta figure out vatozones belt numbers to get a bit longer belt.

Did the install, went to a local a/c shop for hoses.

Pressure hose, cut the metal portion, tig'd on a new fitting, made 2 new hose done.

I don't sevice by weight, I use temp probes, 2, one in the center the other moved from side to side, tells me if my blend doors are happy.

Last but prolly the most important is a quality fan clutch.

 

[Lee]

So with this stuff or something like it there is no reason to change the 710 used in the R12 system? No need to add any, either?

The tractor had a leaky schrader valve, which I fixed with a R134 adapter schrader valve. My manifold gauge is R134, so I needed to adapt it anyway. I vacuumed the system, held it under vacuum for ~30 minutes.

I used 4 oz of Red Tek oil, 4 oz of Red Tek seal conditioner, and 3x 6 oz cans of Red Tek refrigerant (I think it only took 2.5).

 

[TRINDU]

Here's my long bed extra cab 4.3 5speed 4 mismatched 245s, top post yard sale battery with auto zone adaptors, bed cut for the fuel pump, half inch door sag veehickle:

Where are you west of 35?

If you like that rust bucket. Just order everything for a 94+ Chevrolet with the same engine and convert to 134

 

[[486]]

in for propane ac tech

school me on ghetto ac

propane is a drop in replacement for r22

the reason I use a little tiny bit in my own shit is because r134 doesn't carry mineral oil through the system very well, though it doesn't condense, I imagine a little bit dissolves into the liquid r134
might just do nothing and sit in the accumulator
I'd much rather use butane but I lack the adapters to easily use it so...

 

[plym49.2]

I did this on my 92' . The pancake compressors suck.

Absolutely brand new Sanden 508 compressor from Vintage Air, there are options for line clocking. The Sanden should come with the correct amount of oil in it.

Vintage air sells an adapter brackets for the Sanden, $80.

New dryer, do not uncap till you are ready to hook up a line.

New orifice tube, IIRC r12 and r134 use a different size screen.

New condenser just because.

I tapped a blow gun for a -4 AN to pipe union. connect to service port to blow out.

I use a/c flush, some use brakekleen.

You gotta figure out vatozones belt numbers to get a bit longer belt.

Did the install, went to a local a/c shop for hoses.

Pressure hose, cut the metal portion, tig'd on a new fitting, made 2 new hose done.

I don't sevice by weight, I use temp probes, 2, one in the center the other moved from side to side, tells me if my blend doors are happy.

Last but prolly the most important is a quality fan clutch.

That sure looks the best way to do it. High dollar, too. Might have to sell my 285s for a set of mismatched 245s.

 

[plym49.2]

Where are you west of 35?

If you like that rust bucket. Just order everything for a 94+ Chevrolet with the same engine and convert to 134

East of 35.

 

[TRINDU]

East of 35.

Looked like a hill in the background? That's few and far in between in centex.

 

[Mud Rod]

FYI vatozone has vacuum pumps in their loan a tool program.

 

[Tiha]

Help me navigate the varied (and all of it good) suggestions, please.

I guess it depends on what you want as an end result.
Do you want the coldest possible AC?
Do you want the cheapest possible AC?
Or in between?

When we started doing conversions nobody else was doing them. We had no idea what we were doing, and nobody had any good suggestions.
We were replacing everything.
Over time we figured out that you didn't need to and got it down to a minimum.

R134 doesn't leak out as easily as R12 so fixing every leak is not that important.

But that is all about just getting working AC on a budget.

 

[Tiha]

I did this on my 92' . The pancake compressors suck.

Absolutely brand new Sanden 508 compressor from Vintage Air, there are options for line clocking. The Sanden should come with the correct amount of oil in it.

Vintage air sells an adapter brackets for the Sanden, $80.

New dryer, do not uncap till you are ready to hook up a line.

New orifice tube, IIRC r12 and r134 use a different size screen.

New condenser just because.

I tapped a blow gun for a -4 AN to pipe union. connect to service port to blow out.

I use a/c flush, some use brakekleen.

You gotta figure out vatozones belt numbers to get a bit longer belt.

Did the install, went to a local a/c shop for hoses.

Pressure hose, cut the metal portion, tig'd on a new fitting, made 2 new hose done.

I don't sevice by weight, I use temp probes, 2, one in the center the other moved from side to side, tells me if my blend doors are happy.

Last but prolly the most important is a quality fan clutch.

And this is a great example of someone trying to get the coldest AC and a dependable system.

 

[larboc]

Oy vey. So many options from just top it off with 134 and DGAF to flush and replace and everything.

I've a mind to crack a line and flush with 134 or whatever. A few extra cans is less expensive than a vacuum pump.

Help me navigate the varied (and all of it good) suggestions, please.

An idling gas engine makes a better than nothing A/C vacuum pump in a pinch. 50kpaa is better than 100kpaa

 

[plym49.2]

An idling gas engine makes a better than nothing A/C vacuum pump in a pinch. 50kpaa is better than 100kpaa

Yep, used to do that way, way back in the day as teenagers.

 

[plym49.2]

Looked like a hill in the background? That's few and far in between in centex.

Oh, that photo is west of 35. Was at the range and that is why there is brass all about.

 

[plym49.2]

I guess it depends on what you want as an end result.
Do you want the coldest possible AC?
Do you want the cheapest possible AC?
Or in between?

When we started doing conversions nobody else was doing them. We had no idea what we were doing, and nobody had any good suggestions.
We were replacing everything.
Over time we figured out that you didn't need to and got it down to a minimum.

R134 doesn't leak out as easily as R12 so fixing every leak is not that important.

But that is all about just getting working AC on a budget.

Good points and questions. At this point I would simply like to get working A/C on a budget due to budget, time, and how often I use this vehicle.

 

[crisbee1]

fittings and a can of SooperDooper blue can magic instant a/c fixer stuff, with a crappy too short hose and a gauge. prolly gonna need to jump the pressure switch.

 

[M92PV4U]

I replace the one in my dad's '89 blazer every 4-5 years it starts to leak.

I did the conversion on a '89 extra cab c3500 new dryer, pump and orfice tube flushed everything else add pag oil and r134, it works great. I used a scale to measure the amount of r134 that I used.

Edit ester oil not pag

 

[[486]]

ester is more universal (in that you can use it for pretty much all refrigerants), but it goes acidic when it absorbs moisture
pag is not good for r-12, but it doesn't absorb moisture

 

[plym49.2]

I had good luck with Red Tek in dad's John Deere 2755. Red Tek is propane based R12 replacement. I bought it from Amazon, but couldn't find the actual refrigerant there now, just the accessories.

Here's a random Google result:

REDTEK A/C Refrigerant 6 oz cans & Installation Hose w/Gauge - 3 Cans

RED TEK A/C Refrigerant can be used in all R134a applications, including pre-1994 automobiles that have complied with the USEPA Snap Law. Operation: RED TEK A/C Refrigerant possesses similar volumetric refrigerating effects to R134a refrigerants. Operates at lower head pressures and offers...

www.redtekstore.com

I checked out the link and Amazon still sells a lube/leak fix version of this product.

This from the link you provided:

"RED TEK A/C Refrigerant can be used in all R134a applications, including pre-1994 automobiles that have complied with the USEPA Snap Law."

I assume that is the wink-wink that this works on R12 systems.

 

[BIG-O]

I used can duster with Pag oil in my 85 4runner. 4 cans for $11 from Walmart. R152A, very similar pressures to R12.

 

[plym49.2]

I used can duster with Pat oil in my 85 4runner. 4 cans for $11 from Walmart. R152A, very similar pressures to R12.

Now that is interesting.....

 

[grapehead]

I used can duster with Pat oil in my 85 4runner. 4 cans for $11 from Walmart. R152A, very similar pressures to R12.

This sounds genius. Tell me more.

 

[plym49.2]

I checked out the link and Amazon still sells a lube/leak fix version of this product.

This from the link you provided:

"RED TEK A/C Refrigerant can be used in all R134a applications, including pre-1994 automobiles that have complied with the USEPA Snap Law."

I assume that is the wink-wink that this works on R12 systems.

I used can duster with Pat oil in my 85 4runner. 4 cans for $11 from Walmart. R152A, very similar pressures to R12.

So, can simply I use the Red Tek lube/leak and spray duster to top off my R12 system with R12 oil? Or would I have to flush out the old lube and convert to pag oil?

 

[BIG-O]

You gotta get the right stuff with Difluroethane R152A. Get a can tapper that punctures the side of the can. Google it, it's slightly flammable that's why it hasn't went mainstream.

 

[BIG-O]

So, can simply I use the Red Tek lube/leak and spray duster to top off my R12 system with R12 oil? Or would I have to flush out the old lube and convert to pag oil?

Not sure about the mineral oil. I would try and get as much of it out as possible.

 

[Lowrollin70gmc]

You gotta get the right stuff with Difluroethane R152A. Get a can tapper that punctures the side of the can. Google it, it's slightly flammable that's why it hasn't went mainstream.

This is my plan with my 84’s R12 system. I have a new drier, expansion tube, some vacuum time, a little math, and toss R152A at it. I figure if it’s a bust then swap the gigantic A4 compressor for a Sanden and follow the guidance here for r134a.

I will add that some dusters won‘t outright mention R152a, but if it has a CAS #75-37-6 it contains R152a.