What's all needed to convert from r-12 to r134a?

[Lariat]

Dad and I 4.0 swapped his 85 BII using a 92 ranger. All wiring, dash, and blower box is from the ranger, the only thing BII is body/chassis. So, he and I may be going to a pick and pull tomorrow. What vehicles are compatable to pull A/C parts off of?

 

[exbass94]

You're kind of asking two questions at once here: 1. What vehicles are compatable to pull A/C parts off of?
And 2. What's needed to convert R12 to R134a?

These two questions need two separate answers.

Answer to question 1: I'm not positive about this. Did the Ranger you pulled parts from have AC? Did the BII already have AC before the engine swap? If the Ranger had AC, it should've had everything you need. The only thing that might be tricky is bolting the condenser to the radiator support, since an 85 BII is a different body style than a 92 Ranger, and might have a different mounting configuration. It doesn't matter if the parts originally came from an R12 system or R134a system, they're still the same parts and will work with either refrigerant.

Answer to question 2: To convert an R12 system to R134a, you need to first obviously get all the R12 out of the system. Change the accumulator and orifice tube with BRAND NEW units only. Try to change out as many of the O-rings as you can. If some are a super big PITA to change, then don't worry about it too much (there shouldn't be any that are hard on a BII/Ranger though, so change them all). Remove the compressor and drain all the old oil out. Add a few ounces of new oil (if any part of the system had R12 with mineral oil in it, use Ester oil. If all parts were originally R134a, you can use PAG 46 oil) Add the rest of the oil to the new accumulator. Install all the other components, install the adaptor fittings on the service ports. Evacuate the system and check for leaks, and recharge. Done.

 

[Lariat]

yes both were ac vehicles. So all we need is the accumulator, o-rings, orifices, and new oil?

 

[exbass94]

And the adaptor fittings for the service ports, and some refrigerant. That should be all you need, assuming the lines/hoses will work. I would imagine the engine bay of an 85 4.0 BII should be almost identical to a 92 4.0 Ranger, so there shouldn't be any problems with routing the hoses.

 

[97RangerXLT]

one thing I might add here, is that you might want to change out the flexible hoses. the original 85 or 92 were designed for R12 and are probably not the barrier type hoses that the R134 systems have, and being over 20 years old won't help R134 has much smaller molecules and will leak out of the older style hoses a bit quicker. Not sure whether or not a 94+ hose setup will connect correctly to the 85/92 system, but worse case you might be able to have an a/c shop retrofit the existing flex hoses with a barrier type hose, or even order one already made.

Exbass has it nailed for the overall picture tho..

 

[4x4junkie]

I seem to recall reading somewhere when I was doing my conversion that USED R-12 hoses are OK with R134a, but new ones are not (I don't recall the exact details of why though, might've been something along the lines of the mineral oil molecules creating a pseudo-barrier within the rubber or something).

Regardless, I'd replace the hoses too for the simple reason they're 20+ years old. Any new hoses you buy today should be of the barrier type.