A/C question

[nova3795]

so i got a 1972 J-2000 Custom Cab 360 V-8 and it needs a referigant charge. since r-12 is now illegal since DuPonts patten expired and R-134a was invented, can one use the r-134a conversions kits sold at say wal-mart or where ever or do i need to take it into a shop. and yes i know u need an EPA cert to remove r-12, there is how ever none left in my A/C system. thank you very much

 

[elevatorman]

It is wise to get the system evacuated and have the vacuum pulled down to look for leaks prior to recharge and remove all existing residue.
My understanding is you can do the install of 134 without any trouble yet the existance of any R-12 and or remaining oils can actually contaminate the sytem once you change it over as it mixes with the 134