134a back to R12?

[Inca32]

I have 1975 corvette that has been changed to 134a, old air Pro6Ten compressor & condensor by previous owner. What would I have to do to change it back to R12?

[bohica2xo]

That will depend on how it was converted.

Which oil was used in the conversion?

Other than the compressor, is the balance of the system the original design?

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[Inca32]

Not much was done other then compressor (pag46 oil), I installed new condensor and green seals on it because old condensor had black seals. Everything else is probably factory from the looks of the components.

[bohica2xo]

So no flushing or VIR service?

[Inca32]

VIR looks to be in touched don’t know about flushing but think it must have been performed.

[bohica2xo]

If the VIR was not serviced, the system was not flushed. It is not possible to flush through a VIR

The desiccant bag in the VIR is part of the service - so if the VIR looks "untouched" - it has a 40+ year old desiccant bag that is not 134a compatible inside of it...

The system also still has a few ounces of mineral oil in it.

To do the restoration to R12 requires that you flush the condenser & evaporator completely, pull the VIR & service it on the bench. Then flush the compressor with fresh oil of the type you plan to use with the R12. Hoses & hard lines need to be flushed too.

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