Converting factory AC to use R134a

[jimbosprint]

It works!

AC guy says I could add an electric fan to the condenser if I want it colder. It should be 100 or more next week, that should be a good test.

[F.A.A.benny]

yea guys have ben telling me to join this forum. hopefully I can help some people out

[picklito]

I didn't realize that was you, either! Good to see you here. Do you have an opinion on whether the A6 does better with PAG or POE oil when cleaned well then converted to R134a?

[F.A.A.benny]

Originally Posted by picklito

I didn't realize that was you, either! Good to see you here. Do you have an opinion on whether the A6 does better with PAG or POE oil when cleaned well then converted to R134a?

Thanks. I would say ester oil if the rest of the system hasn't been flushed. Pag is good if everything is clean. Ester is what we used where I use to work. And that place is very well known for classic automobile ac/heat restoration.

[picklito]

Is there any disadvantage to using ester? I've cleaned it best I can, but if ester works just as well why not avoid incompatibility and just use ester?

[Bigdav160]

This is what I was told by an ACDelco engineer...." It is hygroscopic and it will release the water under compression in the compressor and cause erosion. There's a reason none of the OE's use ester."

[picklito]

I've decided to go with Delco PAG-150. Evaporator has been professionally cleaned and pressure tested. Drier is new. Can I just rinse out the hoses, condenser, and compressor? I'ver read in a few places that electrical contact cleaner is a good solvent for old R12/mineral oil and it's cheap. Thoughts?

[Katrina/10]

Originally Posted by picklito

I've decided to go with Delco PAG-150. Evaporator has been professionally cleaned and pressure tested. Drier is new. Can I just rinse out the hoses, condenser, and compressor? I'ver read in a few places that electrical contact cleaner is a good solvent for old R12/mineral oil and it's cheap. Thoughts?

Brake cleaner spray works well.

[RedRoad]

Im starting to collect parts for my K20 Suburban A/C and have to get a large amount of hose to run to the rear unit. I was wondering if anyone has just cut off the fittings for the compressor/condenser/POA from the old lines and just used hose clamps instead? If I do order new hoses I hate to have to cut them in half to add the T fitting that just uses hose clamps anyway.

Is there a conversion schrader valve kit I need to install to the old muffler and valve to use 134?

[MARKDTN]

Originally Posted by RedRoad

Im starting to collect parts for my K20 Suburban A/C and have to get a large amount of hose to run to the rear unit. I was wondering if anyone has just cut off the fittings for the compressor/condenser/POA from the old lines and just used hose clamps instead? If I do order new hoses I hate to have to cut them in half to add the T fitting that just uses hose clamps anyway.

Is there a conversion schrader valve kit I need to install to the old muffler and valve to use 134?

You do not want to use hose clamps on an AC system. I know this is how it was stock, but that is a leak point. You want crimped hoses and fittings. Do it right the first time and it should work well for a long time.

[picklito]

Looks really nice!

I got mine working today after several weeks of work. Complete disassembly and cleaning or flushing of every component. Had evaporator professionally repaired where there were a few leak "tracks." It came back spotless and pressure-tested. New O-rings everywhere. Calibrated the POA to 26.5psi (very easy as it turns out). Stock 45 year old A6 was rinsed way too many times with expensive ACDelco PAG150 until it was clean. New receiver-drier at the very last moment, then obsessive-compulsive evacuation which I left for 3 days. Final one hour evacuation and recharged her today. Have three 12oz cans in there at the moment and I think it needs just a touch more. Original sticker on the compressor says 3.25lbs R12. I'm using 80% which comes to 41.6oz of R135, and 3 cans provides 36oz. At this point the test drive showed 40 degrees at the driver side vent, but by the time I was done it was only in the upper 80's here.

One thing I found interesting, and I'd like to know if this is a useful way of "seeing" that you are finally full of refrigerant: My POA is set to 26.5. As I filled with each successive can, the low side would "take" the can, then pump down to 26.5. After 3 cans it's still at 26.5 on the low side, and 225-240 on the high side. I'm thinking that I need a little more R134 in there so that the low side is just "dipping" into that 26.5 setting? It sits there like a rock right now. What do you experts think?

[Andy4639]

Just a good rule of thumb. Is the system getting cold and is it condensating around the POA valve. If so you should be really close.
Outside temp has a lot to do with how well it will cool also and how much air your moving. Take a look at the chart for outside air temps.

[tdangle]

Great thread! I am getting ready to make my AC work again and have a couple of questions. (factory air 70 C20)

I will be needing a new compressor and a new dryer. I assume I need to change out the o-rings to R134 compatible. I need to calibrate the POA or have it done. I think I also need to have adapters for the connections, Do I need to replace all the hoses? Anything else? I'm open to suggestions. Of course flushing the entire system will be done.

[hdff]

Originally Posted by picklito

Looks really nice!

I got mine working today after several weeks of work. Complete disassembly and cleaning or flushing of every component. Had evaporator professionally repaired where there were a few leak "tracks." It came back spotless and pressure-tested. New O-rings everywhere. Calibrated the POA to 26.5psi (very easy as it turns out). Stock 45 year old A6 was rinsed way too many times with expensive ACDelco PAG150 until it was clean. New receiver-drier at the very last moment, then obsessive-compulsive evacuation which I left for 3 days. Final one hour evacuation and recharged her today. Have three 12oz cans in there at the moment and I think it needs just a touch more. Original sticker on the compressor says 3.25lbs R12. I'm using 80% which comes to 41.6oz of R135, and 3 cans provides 36oz. At this point the test drive showed 40 degrees at the driver side vent, but by the time I was done it was only in the upper 80's here.

One thing I found interesting, and I'd like to know if this is a useful way of "seeing" that you are finally full of refrigerant: My POA is set to 26.5. As I filled with each successive can, the low side would "take" the can, then pump down to 26.5. After 3 cans it's still at 26.5 on the low side, and 225-240 on the high side. I'm thinking that I need a little more R134 in there so that the low side is just "dipping" into that 26.5 setting? It sits there like a rock right now. What do you experts think?

what dryer did you end up going with. also what condenser did you use? planning my ac project right now

[picklito]

Originally Posted by hdff

what dryer did you end up going with. also what condenser did you use? planning my ac project right now

See post #83 above. I had to drill one hole to lower the upper mounting loop about 1" because the drier is a little bit shorter than my OE. You can see Jimbo's upper loop is right at the radius of the drier. My drier sat a little lower so the loop was up around the skinnier part. Drier sits where it sits, because of the tubing, so I lowered the loop a little.

[hdff]

Originally Posted by picklito

See post #83 above. I had to drill one hole to lower the upper mounting loop about 1" because the drier is a little bit shorter than my OE. You can see Jimbo's upper loop is right at the radius of the drier. My drier sat a little lower so the loop was up around the skinnier part. Drier sits where it sits, because of the tubing, so I lowered the loop a little.

what drier and condenser did you get and where?

[picklito]

Originally Posted by hdff

what drier and condenser did you get and where?

I'm using stock condenser and the receiver drier part number in post 83 above.
I have very little time running it, but it's been surprisingly good so far. I think the key is getting the POA valve set to 26.5psi and having a very clean and dry system.

[picklito]

That's the chart I was using! It was 90f in the shop and after 36oz of R134 I had 240/27psi. And yes... there was a little frost...

[Andy4639]

Originally Posted by picklito

That's the chart I was using! It was 90f in the shop and after 36oz of R134 I had 240/27psi. And yes... there was a little frost...

I would drive it for a while and then re check if it's the same then maybe add just a touch more. I think you right on the mark pretty much though!

[Keith Seymore]

Tagging this so I can come back to it.

K

[picklito]

Originally Posted by Andy4639

I would drive it for a while and then re check if it's the same then maybe add just a touch more. I think you right on the mark pretty much though!

Definitely. Drive it and let it tell me what to do. My calculation of 80% of R12 came to 3.4ish cans and I'm at 3. That, and the fact that my low side pressure is riding the set point tells me that a little bit more might be the ticket. VERY happy so far.

[RedRoad]

borrowed my brothers HB gauge set and looks like I need adapter too. Any recommendations?

Picklito, what was your procedure on cleaning and recalibrating the POA?

thanks

[picklito]

Originally Posted by RedRoad

Picklito, what was your procedure on cleaning and recalibrating the POA?

thanks

I used this photo which I can't seemed to download right now. It's frame #210 in this photo series.

[RedRoad]

Originally Posted by picklito

I used this photo which I can't seemed to download right now. It's frame #210 in this photo series.

Can you post the link to the series?

Thanks

[tdangle]

I just got a reply back from Classic Auto Air for a kit which includes the Saden-style compressor, brackets, condenser, hoses, filter/drier and hardware to update and run R134. $800 + $190 for a rebuilt and calibrated POA valve and $60 for a expansion valve. Does this sound reasonable or can I save a few putting something together myself. Sounds like everything from the firewall forward.