R-12 to R-134a changeover question

[scottswierenga]

I've joined the ranks of those of us who have had their A/C system fail for lack of Freon. And that's where my question comes from.

I know that to make the change from the old stuff to the new stuff requires that the system be vacuumed out to have all the R-12 removed...but!!!...if the A/C system that formerly used R-12 has been empty for over a year or more, will all the freon be gone enough to the point that it won't need to be sucked out (since it's "all gone"); and therefore make it safe to use the R-134a kit right away?

 

[4x4junkie]

It will never be "all gone" (and even if it were, it would then be replaced by air).
You absolutely have to evacuate the system completely (pull a full vacuum on it) before introducing the new refrigerant into it.

There's much more that's needed aside from just buying a "conversion kit" also...
To convert it to use R-134a you have to open the system up and flush out any left over mineral oil in the coils and compressor that the R-12 used, since it's completely incompatible with the PAG oils used with R-134a, and replace the restrictor device (orifice tube) and accumulator/drier as well. The fittings on the hoses and all the O-ring seals will need to be changed as well.

You might want to read around some on a couple automotive A/C forums before you do this. I gained a lot of knowledge on the subject by doing this before I converted my '90 over to R-134a

 

[Maniak]

Short answer, you need to flush it (any parts your not replacing) and then evaculate it and fill it.

If the system has been open for a while your receiver/drier/accumulator will need to be replaced. The o-rings are also problably bad by now and depends on how bad things were you may need to replaced everything if your a/c system went through black death (black goop will be coating the inside of everything).

~Mark

 

[scottswierenga]

Thanks for the info, that's kind of what I expected the answer to be. About how much am I looking at having to pay a shop to do all that...cuz I don't have the resources to do all of the job myself.

 

[surf]

I recently had mine done and it was $218 out the door. I was quoted $250 by the Ford dealership. Some shops will quote as high as $1,100 to do a full system replacement.

 

[sector9]

i have never had a problem with not flushing it! just do a vacuum add some new oil and recharge it!

 

[tweakedlogic]

Use brake parts cleaner and compressed air to flush it. I used about 5 of the 24 oz cans from 3M. It's not hard, just time consuming. take everything apart first. leave the evap coil mounted and remove the condenser coil from in front of the radiator. You don't have to remove the radiator completely, just the upper hose, fan, and shroud.

Blow out your parts first to get as much oil out as possible. then spray a bunch of brake cleaner, then more air. Be sure and use a rag and the exit port.

Napa has an O ring kit that's like $8. the orifice tube is $12 I think. the orifice tube is located in the hard line above the right wheel. Carefully remove that with needle nose.
Then put all the hoses and things back together and take it to a shop to have evacuated and charged for $50-$85 depending. If you ahve access to a vac pump you can charge it yourself with a kit.

Like I said, it's not hard at all. just time consuming. the hard lines are the hardest part because I didn't have a large enough wrench, so I used two adjustables.