Why can you not get any R-134 into the AC of a 1988 Jeep Cherokee even though youn are using the proper adapters after having the R-12 evacuated?
You need to have a vacuum inside your system before it will
accept any R-134a. Your local shop should be able to do this for a
small fee. YOU CANT ADD IT IF YOU DO NOT CHANGE THE OIL. The oil in
134a is different then the oil in r12. If you do use it as a
replacement with out changing the oil the oil will thicken up and
clogg your metering divice. but you can by a retro kit first