looking at a 91 cherokee I want to buy
he claims theres a hole in the air con tube
how hard/expensive is that to fix

 

The hose is cheap, the R12 refridgerant is what will be the most expensive part of the repair. You will not save ANY money by converting to R134A refridgerant if you do the conversion the proper way. My advise is to take it to an A/C shop to have it repaired, they will have the knowledge and tools needed. Once the leak is fixed you should have a lot of carefree and cool summers ahead of you.

 

The AC never worked in my 90. Finally, mostly for that Dog there, I spent $45 on the kit from Napa. Kind of choppy, not sure it went quite right. Of course I couldn't "evacuate" it or whatever. Anyway it worked more or less OK. Could be better I think. Outlasted the dog though!