134a conversion questions

[Tiggie]

Thinking about converting the 90 to 134a. A DIY job at that but I want to do it right. I've got the vacuum pump and gauge set.

Planning to replace hoses and accumulator, and any o-rings just for good measure.

Would flushing the system be necessary with Ester oil?

Are all new A/C hoses barrier hoses?

I did this years ago with my 82, but only vacuumed it down and put the 134a/oil conversion combo in it. Wasn't really pleased with the results but I do think the compressor was crapping out and stopping up the orfice tube (original reason for service). I'd like this conversion to be better. Compressor is quiet in this car and still holding a small residual R12 charge.

[TecNickal]

I'd flush system with mineral spirits. When done, lube o-rings, fill components with PAG oil, hook up, and charge up. That's what I've done on two cars and it was fine.

[Tiggie]

Any special tools needed to do the flush?

[sly]

An air compressor and a air nozzle with a rubber tip for forcing the flush fluid through. It would also be a good idea to empty the oil out of the compressor too and replace with new stuff. I don't remember which is better to use with the old R12 mineral oil to keep things from getting stupid in the system (PAG or Ester), but one is a little better. Though, if you do a good job of cleaning the old oil out, there shouldn't be any issues. The major issue is replacing all the line seals and making sure you have a complete vacuum and as little moisture as possible in the system. Pulling 23-24 inHg is good enough, but pulling 26-28 is better. I have that cheap bypass pump from Harbor Freight and can manage 23inHg after about 30 minutes of off and on pumping. If the system holds that for an hour, you're good.

[Giraffe]

I was actually googling just today about this as I'm looking to do it for my car as well. A/C is no longer charged (zero R12 in the system) and I would like to see if I can get it running in time for the next Texas summer. Here is an old, no-picture write up I came across. It's specifically for a fox Mustang, but most of the principles are the same.

http://www.veryuseful.com/mustang/te...onversion.html

[knucklehead0202]

Stoked that I've had 2 cars in a row with working R12 systems. I reckon you folks in free states can still get that shit can't you? Here in California it's about like buying free-market plutonium, but I actually have a connection. My system is good so I may call in the favor at a later date if I switch to an HO accessory setup, but otherwise my air works great, much better than 134 shit. Interested in this, however, as i'm sure there will come a day I have to deal with it.

[TecNickal]

Exactly what Sly said
Forgot about flushing compressor out.
Mine had Black Death in it :-/

[gadget73]

Not sure if I'd do mineral spirits. It doesn't evaporate worth a damn. Unless you do a whole lot of purging, its likely going to have some laying in there, and its questionable what that might do to the PAG oil.

[sly]

The cans of AC system flush are pretty cheap for the small one. You don't need a whole lot.

[gadget73]

Thats what I've used in the past. Not sure what the magic potion inside them are, might actually be mineral spirits for all I know.

[Tiggie]

Good advice guys. Thanks!

Got some plans for the 90 if someone doesn't buy it out of my yard before summer. I'm getting older and A/C is my friend.

[DerekTheGreat]

Everyone says that R12 works better for these since the system was designed for it and something about 134a likes a bigger condenser.. Well Ashley's '89 was still running R12 when we converted it and it's just as cold as it was before. My system was dead when I got my '88, I revived it but the compressor shit itself and had to be replaced. Now that that and the accumulator is new and combined with that special ceramic window tint my car's cabin can be a freezer if you wish.

[gadget73]

There is a later condensor that is a more efficient design. Possible its even what you get now if you buy a replacement. Its not so much physical size, its more about flow capacity. The stock Panther one actually does fairly well and conversions go fine on these cars. Other vehicles, not so much.

[tjc78]

My 89 LTC was converted on all original parts, the 89 MGM was still R12 on all original parts. No doubt the MGM was colder but both did the job just fine. The MGM might have been better in stop and go traffic, but that is a box Panther problem anyway. The lack of flow without electric fans causes the problem. Heck even my 04 got warmer sitting in traffic when not on MAX (recirc).

[Giraffe]

I'd like to see how my 90 GM fairs converted with the stock parts during a Texas summer. I don't think I'll be able to scrounge the funds to get it done in time for this year, however. I'll just drive the Mustang when it gets hot.