Whenever you retrofit a system to R-134a you should replace all the?

Whenever you retrofit a system to R-134a, you should replace all the oils, seals, and gaskets to ensure compatibility with the refrigerant. R-134a requires a different type of oil (such as PAG or POE) compared to R-12, which can lead to system inefficiencies or damage if not replaced. Additionally, old seals and gaskets may not be compatible with R-134a, leading to potential leaks. It's also advisable to replace the receiver-drier or accumulator to remove any contaminants from the old refrigerant.