Anyone know what material the inner tube of the original AC hoses as it came from the factory was made of for W123? That is what the OP wants to know. He is not interested in using R134a nor will he be crimping on new hoses. He wants to use the original hoses with Red Tek 12a refrigerant.

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked