Ad0911

Reading all of this, it seems like there is nog good alternative to R12, or do I read it wrong? What is the correct way of replacing the R12? Suppose you have a new dryer and a reconditioned compressor (I take it the rings will be replaced in that compressor). Is there anything else that needs to be replaced in the system? Are there any parts at the evaporator side that need to be replaced? How to get there? It's burried inside the dash.

FreedP

+1

Will Subscribe to this Thread.

dprantl

The only safe viable alternative to R12 right now (and has been for years) is R134a. It does reach higher pressures and is not as efficient , but converted properly should still freeze you out of the car. It is also still very cheap and convenient.

Dan
'91 928GT S/C 475hp/460lb.ft

Dozman

Lizard,
R134a is 10% less efficient as R12. R134a by molecular makeup takes longer to cool to capacity as r12 when the system is started up. With R134a you don't receive the actual temp drop across the coil right away compared to r12.

R134a is the worlds worst green house warming refrigerant manufactured ever. Matter of fact Dupont wants to have it phased out early, and replace it with 1234yf, an experimental ref. that dissipates in the atmosphere within 5 days. Problem is it is slightly combustible Honeywell will not disclose what happens to seals, oil, components inside the systems if the system is not evacuated to 500 micron.
1234yf is actually flammable. A major car manufacturer was going to start using this in 2014 car lines, till one of the cars charged with it, crashed and the ref. during the crash leaked and also caught on fire. The 1234yf was mouth balled for replacement till the flammable issue is resolved.
r414b has inherently oil affinity problems as well.

R12 can be found at any refrigerant "reclaim" not recyclers, readily.

Randy V

Best way is to select 'subscribe' from the Thread Tools dropdown located at the top right of any thread.

otisp

As far as the chemistry is concerned, I agree - 134a is a really powerful greenhouse gas. Just less ozone depleting than R12. Problem is that the manufacture of R12 was banned in the 90's in the US, so the supplies are going to dry up completely at some point. Sounds like the 1234 won't work yet either.
It's an interesting problem, and there are definitely some compromises that will have to be made.
I just went ahead and recharged my 928 with 12a last night. It's cold now, I'm happy. Until I explode I guess.

Dozman

The montreal protocol of 1993 is where the phase out of R12, R22, R11, R134a started from. Basically this coincides with DuPont loosing its patent on R12. R12 is not banned, it just can not be manufactured and brought into the US. There are some countries south of our border that still make R12, but can not be brought in the US legally.

1234 will never work as a replacement, due to flammability. The cost of factory charging a car is reported at $120 per car, compared to $4 a car for the manufacturer... COST alone, and availability is another reason.

The supplies of R12 will never be depleted. The amount of R12 reclaimers across the country have on hand stipulates this. The cost of R12 actually has gone down a little bit every year for this particular refrigerant.

I enjoy having a few hundred pounds of R12 for myself and friends...

otisp

So if they're still producing, is there a big "black market" for r12 from Mexico?

txhokie4life

I have to have my compressor rebuilt (clutch seized I think)
-- Prior to that I think my AC was working, but as I was in the midst of refurb, I'm not sure how well.

I don't have R12 available -- so can someone point me to what I need to do goto R134a?

thanks,

mike (in austin not Canada)

j.kenzie@sbcglobal.net

Hi Mike,
To do the conversion absolutely correctly you should flush each system component, change all o-rings (maybe 20 or so), rebuild hoses with barrier type for 134, install ester oil, new receiver/drier, evacuate and recharge with roughly 80% of the r12 weight in r134. You need to add proper oil to compressor after removing old oil. You might upgrade your condenser, expansion valve and change pressure switch to a 3 way.
OTOH some people take their car in for a quick conversion which is recover old r12, evacuate system, and recharge with r134.
If you care about long term durability, choose option 1.
Good luck,
Dave

Dozman

hot shot, MP39 AND 414B have very low oil affinity. This being said there is a high very compressor failure when these refrigerants are retro fitted into systems such as vehicles.

1234... is an experimental refrigerant to supposedly replace R134a. problem is, it is made with butane and is flammable which one of the auto manufacture has seen first hand. This refrigerant is scrapped as a replacement. Right, now there is NO clear replacement for R134a drop in replacement in the near future.

txhokie4life

Even if I don't keep the car forever -- I treat my refurb work as if I will (within reason)

In for a penny in for a pound :-( I don't have rear AC -- so that will save a valve and a few o-rings. I'm on the fence about the hoses -- but the rest of it I plan to do.

When I have the compressor rebuilt -- I will specifically tell them I am using R134

jleidel

This thread looks fun... I was just about to start into my AC refresh. The original plan was to refurb and refill my R12 system. Still wavering on whether to do the conversion to R134a.

SeanR

If you have it apart and can take the time to change out the seals/oil.....go 134. Had some dip**** try to sell me a tank of R-12 today for $1500.00. Told him to go put the tank up his arsehole.

dr bob

Jeeze... Call when you need some enough to pay that kind of $$$, and I'll part with the cylinder I've been hoarding for cars I no longer own...