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Old 11-10-2020, 10:01 PM   #1
VolvoLatAm
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Default Low budget r12 to r134a conversion

Couple of questions.

I have a 1982 244 with the old r12 system for the ac
York + basic drier without any electronics on it, here are the photos:
https://freeimage.host/i/FFLjdN
https://freeimage.host/i/FFLw7I
https://freeimage.host/i/FFLXgp
https://freeimage.host/i/FFLP7S

I plan to add:
-a used later style compressor + mount from a 760 or 940 to replace my york r12 compressor
-o ring kit, new drier, new expansion valve

Here are the basic parts I plan on ordering:

Four Seasons 38607 expansion valve
https://www.amazon.com/-/es/gp/produ...KIKX0DER&psc=1

Four Seasons 33264 Drier
https://www.amazon.com/-/es/gp/produ...KIKX0DER&psc=1

universal o-ring kit

only 1 of the hoses in the current system is not new.

I already checked with a test light that my compressor on-signal is working from the instrument switch via the green wire.

Should I clean the system out with the older parts not to contaminate the new drier and expansion valve? I am re-using the condenser + evaporator core.

I plan to suck out the system and wait a couple days (instead of an hour or so) to make sure there are no leaks.

I am also worried about the combination of "whatever was in the system" vs. adding Pag, Poe, or Ester. In my country esther is more available than Pag. Poe is impossible to find.
I have read the dave barton guides and numerous others here but still have uncertainties about fitment of the expansion valve+drier and my plan.
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Old 11-10-2020, 10:07 PM   #2
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I'm no expert, not even a little, but I've always heard that old, well used R12 hoses would likely hold R134 better - they're impregnated with oil. New, less used R12 hoses might leak it? Dunno.

I did do a total shadetree R134 swap in an '87 Celica once. System was totally empty, I had a half a hunch it was just from age, not failure. So I sucked a vac on it, let it sit overnight, still held the next day. So I got a cheap drier on RockAuto, installed that, and squirted it full of R134. Didn't even bother changing the valves (heh). And? It worked fine for the next 12 month until my daughter killed it. She was hard on cars for a while.
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Old 11-10-2020, 10:15 PM   #3
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I have new r134a hoses. The expansion valves are cheap. My biggest worry is that they dont fit the r12 evaporator core as most people replace the evap core as well when doing the expansion valve.
I agree that some people get lucky with no leaks. I live in a climate of 80degrees F but not much more. Not expecting 36f from the vents.
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Old 11-11-2020, 02:18 AM   #4
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I had a 1990 240 and I just put an adaptor on the back of the compressor, sucked it down, added 2 oz Ester oil, charged it BY WEIGHT with R134 at approx 80% of the R12 capacity, and had working A/C. It worked pretty well. 90 degree ambient. approx 45 degree vent temps.
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Old 11-11-2020, 03:16 AM   #5
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Quote:
Originally Posted by ZVOLV View Post
I had a 1990 240 and I just put an adaptor on the back of the compressor, sucked it down, added 2 oz Ester oil, charged it BY WEIGHT with R134 at approx 80% of the R12 capacity, and had working A/C. It worked pretty well. 90 degree ambient. approx 45 degree vent temps.
The r134a adapers are cool on the r12 style compressors, I heard the t-style works best as it is easier to reach underneath the power steering pump. My r12 york-style compressor has a bad bearing, and likely needs to be re-sealed. A friend is sending the later style pump/mount. I plan on doing the r134a/ester calculations before any fluids are added. I have heard success with your method for upwards of a couple years of cold ac.
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Old 11-11-2020, 03:27 AM   #6
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You only need ONE port to work on an A/C system. I use a machine to do A/C. I bought a $10 adaptor from the part store and screwed it on the back of the compressor. It would only fit on ONE of the ports back there.

You could just do a fast "flush" with some brake cleaner and compressed air. I put 2 oz oil for the condenser, maybe an oZ for a new drier?, skip the compressor oil balance. meh.

POE is for hybrid electric vehicles.

I would just vacuum it down, then add 2 oz oil, charge it up, and then go go go. (wait, you don't have an oil injector tool) You can always just dump oil in a hose.
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Old 11-14-2020, 01:40 AM   #7
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Do nothing, including no vacuum pull, and charge with Enviro-Safe. 6 oz's is equivalent to 18 oz's R12. Works better than 12, and has giant molecule, so much less leak prone.
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Old 11-15-2020, 07:04 PM   #8
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Quote:
Originally Posted by ZVOLV View Post
I had a 1990 240 and I just put an adaptor on the back of the compressor, sucked it down, added 2 oz Ester oil, charged it BY WEIGHT with R134 at approx 80% of the R12 capacity, and had working A/C. It worked pretty well. 90 degree ambient. approx 45 degree vent temps.
I did this same thing. Lasted about 3 years before I had a leak at the adapter. Now I'm going to add a T fitting to low side hose, much easier to charge this way.
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Old 11-22-2020, 10:08 PM   #9
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found out that on the '82 I am missing a hole for the newer style mount, hmmm
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Old 11-27-2020, 12:41 AM   #10
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Quote:
Originally Posted by VolvoLatAm View Post
I have new r134a hoses. The expansion valves are cheap. My biggest worry is that they dont fit the r12 evaporator core as most people replace the evap core as well when doing the expansion valve.
R-134a-spec expansion valve will fit your evaporator just fine. No need to put in a new evaporator if yours is OK.

Quote:
Originally Posted by VolvoLatAm View Post
found out that on the '82 I am missing a hole for the newer style mount, hmmm
That will have zero effect on mounting a new bracket in practical terms. I've got a B23F running the newer style mount for about 12 years now.
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Old 12-01-2020, 05:42 PM   #11
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Quote:
Originally Posted by Wren View Post
R-134a-spec expansion valve will fit your evaporator just fine. No need to put in a new evaporator if yours is OK.



That will have zero effect on mounting a new bracket in practical terms. I've got a B23F running the newer style mount for about 12 years now.
Can I see a picture of your ac mount? Did you just use the other bolts?
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Old 12-01-2020, 09:16 PM   #12
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See: http://turbobricks.com/forums/showthread.php?p=6082589
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Old Today, 12:00 AM   #13
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Quote:
Originally Posted by stove View Post
Do nothing, including no vacuum pull, and charge with Enviro-Safe. 6 oz's is equivalent to 18 oz's R12. Works better than 12, and has giant molecule, so much less leak prone.
Personally this stuff did not work in any of my cars. I really have no idea why.

I charge all my R12 cars with propane. A $3 bottle will charge a few cars. Works great and only costs a few bucks which is nice since it usually takes a few tries to fix all the leaks.
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