I have a 70 chevelle BB (402) with factory air. I am ready to start putting it back on and I would like to convert to r134a. What parts do I have to replace? Like the POA valve with a different one? Is the expansion valve still used?. I was getting ready to buy a new a6 compressor and the old one was non superheat I think and do i need to get a superheat type? And does it have to cycle on and off? I also plan to replace the condenser with one the aluminum ones from ac kits.com. Any help greatly appreciated.
jim70














b

http://www.autoacforum.com/categories.cfm?catid=20 Heck, just take it over to their place and let them do it, or sell you the parts...you can ask the questions on the forum...

Took your advice JJ'65 and did a lot of research at the autoacforum and found out that my poa valve was bad anyway. At least I know what direction that I going now.
Sorry about the late response-busy and all.

How did you determine your POA was bad?

I found this:

Minimum requirements for converting a system to R134a.

If system has any refrigerant R12 left in the system it must be reclaimed by an approved recovery machine.

Accumulator/drier must be replaced with an R134a compatible replacement. Conversion fittings and label must be added to the system. Label should have the amount of R134a used and quantity and oil type listed. If vehicle is not equipped with a high pressure cut off switch it must be added.

That is the required minimum! Flushing the system to remove the mineral oil and debris should also be done. R134a and mineral oil do not work well together so leaving it in the system with R134a is not recommended! O-rings should be replaced with either NBR or HNBR replacements. Adjustment of the pressure cycling switch may also be needed to achieve the best performance. In some cases an upgrade of the condenser may be required to achieve the original performance.

There are many different suggestions when charging a R12 system with R134a. System must be evacuated before starting the charging procedure. I suggest you start with about 70 percent of the original R12 charge and add an ounce at a time until vent and pressure readings reach the best available results. Remember it is easy to over charge a system with R134a so patience is important.


What's this high pressure cut off switch they speak of?

How do you flush out the system???

What are the conversion fittings?

Perhaps someone makes a kit with all the parts needed to convert R-12 to R-134a??????

I've converted a few R-12 systems over to R-134 by just flushing the old refrigerant oil and putting in new oil.
I never changed anything except the refrigerant lines to compressor O-rings (since I had to remove the compressor to dump the oil out anyway.)
I had better working systems when I put the same amount of R-134 in as the R-12 they held previously.

None of them cooled quite as good as before with the R-12 doing it this way but worked good enough.

Dean what did you use to flush the old oil out with?

I've asked this question over on another board.....Im being told you can buy a conversion kit at K mart and Wal mart? Is there any truth to this?

Dean what did you use to flush the old oil out with?

I've asked this question over on another board.....Im being told you can buy a conversion kit at K mart and Wal mart? Is there any truth to this?

Usually the best thing is to flush it with an approved type of alcohol. You'll probably need a vacuum pump to do things right though..