A/C upgrade

[zulustyle]

Howdy,
I'm in the market to purchase a 81-87 K5 within the next couple of weeks. So far I've looked at a 86 and a 87 in good mechanical condition as well as straight bodies and at a reasonable price. The A/C systems for the vehicles I've called about and actually seen are shot. My question is how much of an overhaul,headache,and expense would it be to convert/replace the old A/C system to a new one. a working A/C is a mandatory condition for owenership so says my commader-in-chief (a.k.a. "the wife")

 

[maynardogle]

Well zulu ol buddy I found your post while searching "ac upgrade" I have an 84 K5 with the infamous A6 compressor and the old R-12 has just about all leaked out. I put myself through one R12 to R134 AC upgrade on my 85 suburban about 10 years ago and I wasn't happy with the result. It never blew colder than about 55 degrees and that wasn't enough out here in CA. At that time, I researched a lot of forums for the right way to go and was told that sometimes it works...and sometimes it doesn't. I learned the following... You have to flush all the old oil out of the system before you upgrade to R134. Compressed air and brake cleaner are good for the evaporator and condensor, but old hoses should be replaced. If it is not too old, the A6 compressor will pump the new R134 molecule, but if you are replacing the compressor anyway, upgrade to a Sanden. They are more efficient and use less horsepower. On forum I saw blamed poor performance on the size of the old condenser. They said to make it work right you need a bigger one than was Ok for R12. Another forum blamed poor performance on the amount of R134 installed. Too much is as big a problem as too little and the tolerance on the load is more critical. My goal is to pull this off for under $300, assuming I don't have a leak in the evaporator or condenser. I hope you (me too) get a good response to this post.