Hi, I just picked up an 85 F-150 with the 351 H.O. and c6. The ac works but it is leaking a little and I think it uses the old r-12, and that stuff is hard to get. I know you can convert the old systems to the new r-134. Is there any kits available to do this or do I have piece something together? If I need to piece it together, what do I need to get?

 

It's not particularly difficult, but you really need to have access to a good AC machine to do it. You have to evacuate all of the R12 that you can, then flush the system to get all of the old mineral oil out. Mineral oil and R134 don't mix, it causes bad stuff to happen. After you get it all flushed out, you'll need to disconnect all of the hoses and replace all of the seals (And probably orifice tube as well, since the one that's the correct size for R12 might not be the correct size for R134, but you'll have to play around with sizes to get the right one). You can replace your condenser and evaporator as well, but you don't have to. Living in Texas, I would, just because I want the best cooling I can possibly get, but if you don't be sure to flush those out as best you can with a flush tool.

I would also recommend, at this point, replacing your compressor. Who knows how long that thing's been on there and how many miles it's got on it, plus, again, R12 compressors aren't as good with R134 as a new compressor would be. I'd also want to replace my accumulator as well since there's probably a bunch of junk in there as well. The accumulator acts as a filter and a dryer, so the dessicant (drying substance) inside of it is probably old and used up and it's full of little bits of crap as well.

After you've replaced and lubed all of the seals and metering device (Oriface tube), reconnect everything, fill your compressor, condenser, evaporator and accumulator with PAG oil (and ONLY PAG oil, any other type will possibly ruin your system at this point), put on the conversion nozzles on the R12 hookups and charge it with R134 and some UV Dye to check for leaks.

It's honestly not really hard, but it can be very time consuming and you have to have the right tools to do it.

Here's a link to a simple kit that's got the basics. http://www.autozone.com/autozone/acc...ntifier=313536

 

Here we go again. Get rid of the r12 in the system. Go to Harbor freight and buy their vacuum pump for about $100 on sale, and a set of gauges for $40 on sale, or get one of the kits with a gauge in it.

Put it on a vacuum and let it sit for a couple of hours, and then stick the conversion kit in it that you can get from Walmart of any of the parts stores. They come with a oil already in them that works without flushing the system(ester oil). The kit will come with conversion fittings, so screw them on first, use the gauges and the vacuum pump to pull a vacuum on it for a hour or so, then hook the cans up and put them in. It works.

If you have a minor leak in the system(usually the compressor seal if the front of the compressor is oily) you might get lucky and only have to put a can of r134a in it once a year. That's what I do with my truck, and it will work for a year or so before it goes down enough to need some.

You will get lots of opinions on how to do it, some people are in the business and are particular about how it's done, some people want their system to work perfectly and be very cold, etc. If you just stick it in, it works 99% of the time, and is cold enough for me. I have even heard of people leaving the r12 in it and putting r134a on top of that, but I will draw the line there and say take the old out before you put the other in.

 

It's illegal to dump R12, it has to be recovered. Now if the system is empty, all the R12 has already leaked out, then no recovery is needed.

Hoses and seals for R12 are not compatible with 134a. The 134a molecules are smaller and will leak out. However, in systems that have been in use for a while, the openings in the hoses/seals get plugged with oil, R12, derbies, etc and they usually do fine. Any replacement hoses or seals should be 134a compatible and anything you open should be resealed with 134a seals.

Definitely pull a vacuum on the system. By lowering the pressure you lower the boiling point of water and cause any moisture in the lines to boil off and be sucked out.

134a needs to be weighed in to be most effective. Find out how much your system is supposed to take and estimate how many cans you'll use and stop there. 1 and 1/2 cans, 2 and 1/4 cans, etc.

DO NOT DO THIS. You now have a blended gas and if you ever go to a shop to have your system worked on and they test your system they won't evac it. You'll have to pay big bucks to have the gas properly disposed of. If they do take it now they have blended gas in their tank and will get hosed when they turn the bottle in. It can't be reclaimed or recycled and must be burned off as hazardous waste.

I have my EPA 608 and 609 cards...

 

Thankyou for the replies. I do have a can of r-12 I might just put in for the up coming summer, then I'll convert it at a leter date. It seems like it could be pretty tedious.

 

You evac the system, get the kit that's compatible with mineral oil and put it in. You'll need to install the adapter fittings and vacuum it down but all in all not too bad.

Now if you need repairs... That's a different story. But if you buy the vacuum pump and gauges you can fix your own stuff. You should get it recovered but if it all leaks out because you need to fix your system then it all leaks out...

Once empty there's no need to evac.

 

Yes, I tried to do the right thing and get the old r12 recovered. I called around, none of the shops would do it for me, the one that would wanted $100 to do it. I thought to myself that maybe one of the local junkyards would do it, or have a idea who would do it, since they have so many old cars with r12 in them, but each one I called seemed to clam up and know nothing about it, I guess they thought I was a government agent.

So by the time I got to converting it over, all the r12 had leaked out anyway so I didn't have to worry about it

 

Duplicate thread.

 

The seals need to be replaced, the existing hoses will work just fine with R134. I ran my truck that way until I converted to EFI. At that point I installed a complete system from a 1996 truck. Archion is running R134 in his truck and my "adopted" son-in-law has it that way in his 1989 truck.

Franklin2 is correct in that you can buy the kits at most parts stores or Wally World. Hardest pieces to come by are the fittings. At least you won't have to deal with spring locks.