R12 to 134A

[Ol Blue 2018]

1987 V10 350 TBI 4x4

Just sharing my experience ..... Maybe it will help someone

After sweating all summer in the Florida panhandle, dreading a costly A/C conversion from R12 to 134A (which I had in my head would be many parts to replace including a compressor, evaporator, condenser, orifice tube, etc)
I stopped into my local A/C shop to see what kinda dough I needed to save up before the retrofit.

He said: Let's drain it, flush it, blow it out, seal it up, change your fittings, O ring here, O ring there, check your orifice tube, clean or replace it and see if she holds vacuum. If yes, fill it with 134A, oil the compressor and call it done!

Me: I will have her back at 630 tomorrow morning!

This plan worked out great and I have a big a$$ grin on my face driving that baby now ! It's a game changer!

I thought there was more to the conversion ( and maybe this is not 'proper') but it works great so far.
He ended up finding a missing bold somewhere down under the PS pump/ compressor bracket and fixed that and tightened up the belts too for $275 out the door. That was about 2 weeks ago and she blows cold now.

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[hatzie]

As long as it was flushed out completely, the compressor oil was dumped, the fittings swapped, a new accumulator/dryer installed, R12 O-rings swapped to R134a compatible, and the compressor & system has a full but not overfull charge of Ester oil you should be good to go.

You may get away with the old dryer if the system was still sealed but I'd get it swapped out if the system was leaking... the compressor, aluminum hardlines, and evaporator will thank you.

I see he used oil with UV dye. Good to have. Blacklight will show any leaks.

 

[Backfoot100]

1987 V10 350 TBI 4x4

Just sharing my experience ..... Maybe it will help someone

After sweating all summer in the Florida panhandle, dreading a costly A/C conversion from R12 to 134A (which I had in my head would be many parts to replace including a compressor, evaporator, condenser, orifice tube, etc)
I stopped into my local A/C shop to see what kinda dough I needed to save up before the retrofit.

He said: Let's drain it, flush it, blow it out, seal it up, change your fittings, O ring here, O ring there, check your orifice tube, clean or replace it and see if she holds vacuum. If yes, fill it with 134A, oil the compressor and call it done!

Me: I will have her back at 630 tomorrow morning!

This plan worked out great and I have a big a$$ grin on my face driving that baby now ! It's a game changer!

I thought there was more to the conversion ( and maybe this is not 'proper') but it works great so far.
He ended up finding a missing bold somewhere down under the PS pump/ compressor bracket and fixed that and tightened up the belts too for $275 out the door. That was about 2 weeks ago and she blows cold now.

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I just did exactly the same thing a couple of months ago (also in FL). 86 Sub w/rear AC. Everything was working great. Even was colder than what I was expecting from reading up on all AC posts I could find.
Then a week ago the compressor started making a God awful squealing sound and then seized up. Now I'm reading up on all the horror stories of replacing the compressor with another R4 unit that may only last a week....or less.
Haven't found any kind of Sanden conversion for an R4 on the drivers side as of yet (Short of converting to a serpentine setup and relocating to passenger side...which I'm really not thrilled about either).

The AC guy I took it to seems to know his stuff. I called him up and he said we definitely would need to vacuum it down and clean it out after replacing the compressor.
He said most guys with the same compressor just go to Advance and get a new one with the lifetime warranty. He seems to have had fairly good luck with that.

 

[hatzie]

The big mistake a lot fo folks make is to assume the dryer is OK just because the sytem is still closed. If it's not working then it's been open to some amount of humid outside air... the dryer, in this case, is DONE. Stick a fork in it and get another with fresh desiccant.

If you flush the oil and crud out of the system and install a NEW R4 with a new dryer and a new orifice tube/filter with a charge of brand new Ester oil it'll last several years. The better solution is to flush the system and install a new Sanden compressor with a full charge of ester oil. If you have the smaller passage condenser you should replace that as well.

The other thing to keep in mind is the LBS to charge with R134a is not the same as the LBS of R12. You can't extrapolate from LBS called for to LBS to charge. You can easily overcharge the system and it'll stress the already weak Harrison R4 compressor and kill it.