R12 -> R134 between crossover years.

So, until I swapped my engine for a rebuilt one back in March I had a fully charged R12 system in the truck.  Being it is no longer charged and I live in Florida, life kinda sucks at times.  Considering how hard it is to find R12, and how expensive it is when you can find it, I've been thinking of going to R134.  Unfortunately from what I remember of Heat Transfer, and various other Thermo classes, the R134 won't perform as well in the R12 system.

To solve that, since it is a '93 and in '94 they mandated R134, I am thinking most of the parts will be a bolt on deal.  

Anyone have any thoughts on any of this?  Most of the prices of new stuff on Rockauto is fairly decent, I'm going to have to get new hoses anyways as one of them got kinked while swapping and then developed a pinhole leak that drained the system

I converted an 89 S10 not too long back. Just swapped the compressor (it was bad anyway) and put in a conversion kit (adapter valves basically) and it works great

Swap the receiver / dryer, get a port conversion kit and charge it with a blend (e.g.Envirosafe).  It an easy start and should be 90% of what you had.  If you are not happy then you can do the full swap.

I did that on my 87 Mazda and it worked great and it was cheap.  When the compressor finally went (240,000 miles) I swapped out the compressor, dryer, o-rings and (hardest part) expansion valve and charged with 134 (new oil), works great.  I did not change the hoses, but I did need to drain and flush the system / components.  The r12 hoses will not leak if they are run with r 12 long enough.

I retro-fitted parts of R12 and R134a systems into my old Nissan Hadbody.  Everything used, nothing new except the drier. I used Viton seals, and installed the correct oil for R134a. It all worked fine for the years I had it.

I normally rebuild compressor, add a dryer and use viton seals and it treats me well.

SkinnyG said:

I retro-fitted parts of R12 and R134a systems into my old Nissan Hadbody.  Everything used, nothing new except the drier. I used Viton seals, and installed the correct oil for R134a. It all worked fine for the years I had it.

Did you use an r-134a condenser and evaporator or go with the r-12 ones? 

In reply to Professor_Brap :

You rebuild the compressor yourself? 

In reply to spitfirebill :

I do, I Don't trust remans. 

Dad's John Deere had a bad shrader valve, leaked off the R12.

I screwed an R12 to R134 adapter on top of the leaky valve, used my R134 manifold/gauges, vacuumed, and then filled the system with Red Tek oil and refrigerant.

Worked great.

I have done a retrofit on a OBS f450 using the r134 parts. Quite straight forward

spitfirebill said:

SkinnyG said:

I retro-fitted parts of R12 and R134a systems into my old Nissan Hadbody.  Everything used, nothing new except the drier. I used Viton seals, and installed the correct oil for R134a. It all worked fine for the years I had it.

Did you use an r-134a condenser and evaporator or go with the r-12 ones? 

One was R12, and the other was R134a, but I don't remember which. I -think- the condenser might have been the R134a one. In my research, the 134a components would be more efficient.  Mine worked fine, although I should have added an electric fan so it worked better sitting in traffic.

For those that did the R134 adapter kit, how did you flush the R12 oil out?