AC Conversion

[wildbill23c]

Since the AC in my 88 bronco 2 doesn't work, I will be converting it to R134A here as soon as I get a vacuum pump and gauges. I want to do this right so I went over to the tech section and read up on the AC 101 and the resurrecting your AC articles. Great information in both articles. Planning on doing this on a day I don't have to work so I have all day to mess with it. I need to take the compressor off and drain the oil and replace with the correct oil for R134A, then put everything back together and vacuum it down again.

During the vacuum process does it pull oil out of anything or just air/moisture? What about the old oil in the rest of the system? Do I need to replace all those components due to having the R12 oil in it? Or just the oil in the compressor?

No charge currently in the system at all, so going to do the conversion put some dye in and a charge, check for leaks and repair if any are found, then go from there.

 

[4x4junkie]

Vacuuming removes air & moisture, but little to no oil.
You'll need to flush the old R-12 oil out of each component with solvent (except the accumulator and orifice tube, both of these should be replaced with new).

 

[adsm08]

You should really replace all the lines too. R12 rubber is not as dense as R134a rubber, and R134a molecules are smaller than R12, so the new refrigerant can leak right through the rubber sections of a perfectly good R12 line.

 

[wildbill23c]

Vacuuming removes air & moisture, but little to no oil.
You'll need to flush the old R-12 oil out of each component with solvent (except the accumulator and orifice tube, both of these should be replaced with new).

You should really replace all the lines too. R12 rubber is not as dense as R134a rubber, and R134a molecules are smaller than R12, so the new refrigerant can leak right through the rubber sections of a perfectly good R12 line.

I was thinking the same thing, figured I have to open everything up anyhow to change the compressor oil, plus all the o-rings, may as well just replace all those components anyways. Thanks guys.

Where is a good source to get replacement components?

 

[Doofy]

Rock Auto or Amazon for replacement parts. Even AutoZone had some hoses the others didn't. Components are not that expensive.

 

[wildbill23c]

Thanks, I'll start gathering up parts LOL. The worst part I think it pulling the compressor off, the way in which it is mounted makes it a pain. Would have made more sense if they made the mount so you could attach the compressor and pivot the compressor to put the belt on after you get the bolts in, not try to mount a compressor with the belt attached LOL.

 

[adsm08]

Yeah, I did the lines in My B2 a few years ago. I think I got everything from Rockauto for $100 or so.

 

[wildbill23c]

Yeah, I did the lines in My B2 a few years ago. I think I got everything from Rockauto for $100 or so.

Hmm, thanks I'll start there. Done business with them in the past and had good results. It would just be nice to have working AC before summer hits, seems the B2's are a huge oven in the summer as the only windows that open are the driver/passenger door windows...man those rear vent windows that nobody has ever seen would be nice right now HAHA!!!

 

[Denisefwd93]

If you haven't already torn things I would suggest finding out why it wasn't working, DON'T use compressed air. You will also want a 134 rated orifice​ tube, make sure the compressor is still good, the receiver will have oil in it also,

 

[wildbill23c]

It all works, just not enough refrigerant to make it work properly. I haven't dug into it very far as I don't want the system open until I am able to repair it. Need gauges and a vacuum pump and the orifice tube, receiver, both AC lines, etc. it will be a while, just getting the info I need so I can start getting stuff together. I want it done right the first time, so I'll gladly take my time and get everything I need and do it right.

I've had the work done by a shop in the past but they are pushing $2,000 for this job, and I'd rather learn and do it myself.

 

[Doofy]

I bought a cheap air operated vacuum pump from Amazon and it worked surprisingly well. No one wanted to ship a real good pump to Alaska for some reason. They also had manifold gauge sets also. I didn't need the best...

 

[wildbill23c]

I bought a cheap air operated vacuum pump from Amazon and it worked surprisingly well. No one wanted to ship a real good pump to Alaska for some reason. They also had manifold gauge sets also. I didn't need the best...

I have a couple Harbor Freight's not too far away that carries both for pretty reasonable prices especially with the 20% off coupons.

 

[Doofy]

I actually enjoyed repairing the a/c in the wife's jeep. I mainly wanted to prove to myself that I could fix it. It's still working too! I would imagine that Harbor Freight tools would work just fine.

 

[wildbill23c]

Other than saving money paying a shop to do this, I want to learn and know how to do it myself and this is a great time and way to learn how. It doesn't work now, so if I screw it up I haven't lost anything LOL.

 

[4x4junkie]

You'll need a good air compressor for one of those air-powered pumps to work well... My experience is they need at least a sustained 110PSI (contrary to what any labeling might say).
My 125 PSI Craftsman compressor has a 7.1 CFM @ 90PSI rating. It's only if I pull out the little felt air filter thing from the compressor's intake will it keep up enough (right about 110PSI) to prevent the gauge from slipping under 29in-hg vacuum (and no the filter is not dirty).

Doing it while the engine is hot will also help you achieve a better vacuum (heat from the engine will allow air & moisture in the system to be extracted quicker and more thoroughly).

Or just get a rotary-vane pump.