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'85 Factory AC System -- How to Repair

Shran

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At this point I would not even bother trying to find R12 unless I had a vehicle with functioning system that I trusted. It is just too expensive to mess with anymore... R134a is cheap.

I also would be super hesitant to use HC-12a because of how flammable it is. I may have told this story before but my buddy worked in a shop that charged a bus AC unit with propane and it leaked out overnight and blew up the shop when a piece of equipment turned on. I also know for a fact that there are sniffers that shops use to figure out what an AC system is charged with, if they detect propane they will not touch it.

Our AC systems only contain maybe 2-3lbs of refrigerant but that's 2-3 little green propane tanks worth... plenty to do enough damage when it leaks out inside your garage. Better safe than sorry on that one.
 


ford4wd08

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At this point I would not even bother trying to find R12 unless I had a vehicle with functioning system that I trusted. It is just too expensive to mess with anymore... R134a is cheap.

I also would be super hesitant to use HC-12a because of how flammable it is. I may have told this story before but my buddy worked in a shop that charged a bus AC unit with propane and it leaked out overnight and blew up the shop when a piece of equipment turned on. I also know for a fact that there are sniffers that shops use to figure out what an AC system is charged with, if they detect propane they will not touch it.

Our AC systems only contain maybe 2-3lbs of refrigerant but that's 2-3 little green propane tanks worth... plenty to do enough damage when it leaks out inside your garage. Better safe than sorry on that one.
I agree. Big reason I chose R134A. I could have gotten R12 basically for free, but it could have leaked out just as easy.
 

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Been running the AC now for a few months. Works pretty well.

Just have some thoughts I would like some input on.

My cooling isn't great at idle or while stopped. I never hear the pressure switch kick either.

I have the stock mechanical fan with a new clutch as of last year. When at idle, I am not getting enough airflow to cool my new condenser and drop the low side pressure.

I did a quick test this morning. I put my large shop fan in front of the bronco and let it run with AC full blast in the driveway. The pressures began to drop to a good level according to the chart and when I gave it a little throttle, I was able to get the low side down to 22 psi and trip the low pressure switch. Cooling was great inside the cab.

This leads to me think I have an airflow problem. I'm not sure in 85 that Ford put enough into these cooling systems as far as AC, auto trans, etc. I do have a new two row radiator as well.

I know I could add e fans overall, but like the safety next of a mechanical fan, I can always cut off AC and get home if I felt like the truck was getting too hot.

So, I'm thinking of adding a pusher fan to the front of the condenser that is on a relay that runs with the AC compressor. I think one fan won't be too much of a strain on my electrical system as I know fans can be hard on older trucks.

I don't believe if I choose wisely that I'll have any issues with blocking airflow to the rest of the system and in TN we are running AC probably 8 to 9 months out of the year.

Thoughts?
 

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When testing the a/c system for cooling at the centre vent engine rpm is not at idle. Test with rpm at at least 1300 rpm.
 

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I figure that you have the original fan and shroud that it came with. On the clutch, "new" doesn't mean much these days. New condenser noted, and the radiator air passages should have been cleaned of debris and insect remains, and any bent fins straightened.

I don't know off the top of my head, and I'd have to look in an '85 shop manual, but usually a factory AC system package would include seals to help direct air through the condenser and radiator. Typically, these seal pieces were just rubber flaps top and bottom and foam strips on the sides.

Without the seals, air flow will be around and behind the condenser when the truck is not moving.
 

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When testing the a/c system for cooling at the centre vent engine rpm is not at idle. Test with rpm at at least 1300 rpm.
Then when I revved up around 1500 RPMs the low pressure would kick, so that appears to be working correctly then.

Thanks for the tip.
 

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Then when I revved up around 1500 RPMs the low pressure would kick, so that appears to be working correctly then.

Thanks for the tip.
If you do not have one pick up a vent thermometer to accurately see what the temps at the vent are, without one one is just guessing as to the actual temp.

If you've done a convert to 134a getting temps of near close to 42.F from a system that WAS R12 is about as good as it gets.
 

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If you do not have one pick up a vent thermometer to accurately see what the temps at the vent are, without one one is just guessing as to the actual temp.

If you've done a convert to 134a getting temps of near close to 42.F from a system that WAS R12 is about as good as it gets.
I do have a vent thermo. It was below 50 this morning but I didn't have the throttle consistently at 1300 rpm like mentioned early.
 

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I figure that you have the original fan and shroud that it came with. On the clutch, "new" doesn't mean much these days. New condenser noted, and the radiator air passages should have been cleaned of debris and insect remains, and any bent fins straightened.

I don't know off the top of my head, and I'd have to look in an '85 shop manual, but usually a factory AC system package would include seals to help direct air through the condenser and radiator. Typically, these seal pieces were just rubber flaps top and bottom and foam strips on the sides.

Without the seals, air flow will be around and behind the condenser when the truck is not moving.
Also about the clutch, I know they make different grades and seiver duty clutches, that could be something to look into later.

Not sure if there is a motorcraft one out there anymore. I could call into green part sales if I have the part number and get NOS.
 

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You the man Robbie. I do not have those and didn't even know they existed. Guess I can fab some.

With that it should help.
Definitely something that can be fabbed, and I think that it's definitely worth the time and trouble.

You're just trying to block alternative air paths, so the air flow that the fan pulls has to go through the condenser and radiator, and not around them.
 

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Definitely something that can be fabbed, and I think that it's definitely worth the time and trouble.

You're just trying to block alternative air paths, so the air flow that the fan pulls has to go through the condenser and radiator, and not around them.
I've got some leftover insulation material that I used on the headliner and to wrap the condenser box in. I think I'm going to try and experiment with them today and see if I can direct the air flow.
 

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Lots of possibilities, just avoid any materials which will retain moisture. Such as, use closed cell foam (as used in insulation), versus open cell foams (like used in a sponge).
 

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I grabbed my seals from a first generation explorer which are still fairly common in yards around me yet.
 

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