Because you need to open the system anyway which requires the replacement of the reciever/dryer I would suggest that you also purchase a set of adapter valves and regas the system with R134a. It only has a minor reduction in cooling performance but will make it easier for future servicing.

There should be 4 orings under the manifold on the compressor. Make sure you replace them with green orings and NOT black orings. The green orings are compatible with both refrigerents while the black ones don't like R134a (over a long period of time).

Don't be worried about higher pressures of R134a, it should only be recharged with 80% of the R12 charge so the pressures remain about the same. The molicule size of R134a is smaller so it will leak slightly faster than R12. (eg 10grams per year rather than 7grams).

The oil should be topped up about 20mls for a slow leak and 40mls for a large/long term leak. The reciever dryer takes about 30mls as well.

Alex.

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Alex.

MB Tech
Sydney, Australia
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