I would say the duraccol would work real well. Propane is one of the best refrigerants there is but I would be a little scared of that.

134A systems work fine but as far as a retroed truck, that is hit or miss..
Some work good and some don't.. I have had great luck with Ford pick-ups.
I think the bigger the system is the better it does.

I switched my 83 over and you could hang meat in that truck. I did put 4 lbs in it and it did great. I have heard and read that you should put about 80% of the original charge amount of 12 with the 134A. I haven't ever done that and I have had good luck. But then again, AC work is "percision" guess work.

That is crazy for what they are charging you guys. Slide down this way. I can hook you up ALOT cheaper than that.

 

Propane didn't work very well, I ended up killing a compressor that was already on its last leg. Later found out that the pressure is too high to work in an R12 system.

Duracool is a nearly 50/50 mix of propane and isobutane, along with other minor components. All I put in was 18 oz, and with some tweaking of the pressure switch I can make ice under the hood if I want.

You would not believe some of the prices that canadians have to pay for auto parts and service, in general, I drop 50% off the price the average part even after duties and brokerage (dollar is at $0.94 USD so I didn't mention exchange). More if its something fancy like a transmission part.

 

I did a parts store retrofit. Didn't change a single part and it blows colder than most factory 134 systems. I only used 36oz of refer in it too.
This is in an 84

 

i converted my ole 85 and 90 over to 134a and it works great did change orfic tube but other than that nothing else

 

These older fords converted very well. It is nice to see guys having good luck.

 

Alright, so let me get this straight. I can either put money into new seals and pray that it works, just pour in some R134A and see what happens, add some oils which supposedly revamp the system (NAPA) and charge the R134A or look for an alternative refrigerants...need to narrow down the best answer...

From what I have read, I can't leave the system exposed to air very long. That would almost put replacing the seals out of the question. How exactly do you add the refrigerant anyway? I have only seen the systems at the shop that pump the stuff in. I have never seen it poured in as some of your replies might suggest. How do I vaccum the system out? I'm thinking your definition is different from mine (shop vac comes to mind). To be honest, I think this old R12 system just needs to be charged up. It worked to a point when I first got the truck and has slowly dwindled in cooling ability ever since. Need some help getting this figured out before I go tearing into it blindly. Thanks fellas.

-Dave

 

The reason why you can't expose the system to air is because that PAG oil (used in 134a systems) will absorb moisture (humidity in the air is enough) and break down into corossive compounds. Obviuosly, you have an r12 system, so this is not as big a deal, but air in the system will not help.

I think you should still replace all the seals, because 134a is more leak prone than r12 (smaller molecules), I doubt the system will hold a charge for very long. And if you have a low charge, there must be a leak somewhere.

To evacuate the system, you need to pull a vacuum of 30Hg, or as close to that as possible for at least one hour. This evacuates all the air, and will also boil off any moisture that may be in the system. I bought a tool off the web that uses a shop compressor to pull the vacuum (ventury effect), it was cheaper than getting an electric vacuum pump.

To recharge the system, you use the pressure of the container of refrigerant to force the stuff in at the low side of the AC system. Once you reach the minimum charge to activate the pressure switch (you will hear a click if the engine is off), the compressor will start to cycle, and pull the low side pressure back down again, allowing you to continue adding refrigerant.

Some one please correct me if im wrong here, but as I understand it, if converting an r12 system over to a 134a system, you need to replace all the soft hoses and seals since 134a can actually penetrate the rubber and leak over time. Is this actually true, or is some one out to make a quick buck???

Having said all that, heres what I did.

Since I knew the compressor sent gunk through out the system, I dissasembled everything and cleaned it out with acetone and compressed air. This also removed all the leftover oil so there was no guess work with adding new oil. The orifice tube was clogged with "black death" so I replaced that and a few seals that were bad.

I reassembled everything along with a newer compressor, and filled it with 70 psi of air and left the compressor disconnected. Left it like that for a week to be sure of no leaks. After that, I depressurised the air and added the PAG oil to the system (would have used mineral oil, but couldn't find it). Imediately after adding the oil I reconnected all the lines and hooked up the vaccum for nearly two hours (the shop compressor was NOT happy with me).

All that was left is to add the refrigerant, it took a little fine tuning, but it works great. Something that duracool claims is that its actually LESS leak prone than R12 let alone 134a, this is why I didn't bother replacing all the seals, so far, so good.

 

Yes, it is more flamable than std refrigerants.

Did you put a new oil charge in too?

Pressure being too high would more likely be from it being over filled.
Do you have a reference on the pressure of propane?

 

Propane as a refrigerant: (See pages 3 & 4)

http://www.gmcws.org/techcenter/TC41.pdf

 

+

The thing is, there isnt really that much HC in the system to cause real damage even if it were to all go off at once, 18oz of refrigerant is not enough to worry about IMHO. And just like gasoline, propane needs the right mixture to produce an explosion or even a flame, I just don't see that happening easily except under controlled conditions, even if it did happen, there would just be brief flash since theres not enough fuel to sustain the fire. Something else to consider, is that even other refrigerants can catch fire under the right conditions, the oil in paticular is flammable, so isn't such thing as a fire proof refrigerant.

Mark, to be honest, I was able to get it to work breifly with a mix of camping fuel (butane/and isobutane) and propane, but I didn't do all my home work on it at that time, and made many mistakes. For the longest time I didn't even know that my compressor wasn't holding pressure (piston seals were fried).

It might be possible to run on strait propane, but I wasn't able to get it to work consistently like that, so at $12 a can of duracool, I figured on trying to do it by the book.

 

Notice I said more flammable than std refrigerants...
Most std refrigerants have Fluorine replacing the Hydrogen atoms on the hydrocarbon.
So when they do burn they make lethal gases.
Generally they make HF (Hydrogen Fluoride A.K.A. Hydrofluoric Acid) and one good inhale and you are dead...not right away but there is no way to save you...(heart Failure) you can also get it by absorption thru your skin....

 

HOLY ****! I knew there were some nasty stuff in R134A, but didn't realise it was that bad!

I think I'd rather risk loosing an eyebrow or some of the hair on my head than inhale the other stuff.

Is this true for r12 as well, or is 134a the only one with the nasty stuff?

 

Dave, David has is right on but I wouldn't use a drop in gas.. You live in the states so 134A isn't to bad..I can get gas to charge you truck around here for $20..

I would definatly replace the accumulator..I know guys have charged them without doing that but I wouldn't take the chance..You are going to different gas and if it is very old it can come apart inside..It is a filter and has desecant in it. These are very little ***** and if the bag busts the media will go through the system and then you are in for a very bad day..Your compressor willl probably be gone and you have much luck at cleaning out the condensor..I wouldn't take the chance from experience.

You have to vacuum the moisture out because the water will freeze inside you system and clog it up and that will happen at the orfice tube when the gas goes from high pressure to low pressure. That sudden change in pressure is what cause the gas to get cold.

When you put the system under a vacuum water will actually boil and turn to vapor. That is the reason for the vacuum.

 

Yes these gases are bad when you can get them to burn but it is alot harder to get to burn then propane..

Alittle history,, R12 makes fosegene, check my spelling, gas and it is bad..It killed alot of Jews in **** Germany..Bad stuff used by bad people.

 

Alright I did a search for the electric vacuum pump that you mentioned David85, the only thing I found was this:

http://www.autoanything.com/brakes/69A3151A0A0.aspx

Not exactly what I'm looking for I wouldn't think. Do you have any pictures or links to the pump that you used?

Also, I'm looking for more of a step by step instruction for converting this system. I'm still trying to figure out what you are talking about with the eletric vacuum pump and how to add the refrigerant. Are we talking using fittings and lines hooked up to a tank of R134a running to the truck? You have given me good information so far but its not very clear. I'm not very literate when it comes to AC systems either. Never had to work on them before...