Wow, that's brilliant!

 

Easier to just put my answers in red.

 

The way his is set up the water is shut off to the heater in Vent, Max, & Normal A/C.

 

WOW, am I glad I found this thread. Just yesterday I was thinking I should add a heater valve to my '84 and lo and behold...

But I've got a question regarding the AC system. Mine has also been converted to R-134a and I noticed in the original post that you charged only to 80% capacity. Is this the norm when retrofitting, to charge below system capacities. I only ask because I charged the system with 134a and used as much to fill as the decal calls for of R-12. If that's the case, my system is probably over-charged.

It's been so hot here lately that I can't really expect the AC to be THAT cold. It is pretty cool but of course, I always feel it could be colder.

 

Today, it was 95 degrees outside.


My 84 was converted to R134 last year. After running awhile, on MAX A/C, the air out of the ductwork was about 70 degrees. Not ice cold, as my 2011 is, but not too bad. I'm wondering if it should be colder.

 

I would think at least a little cooler. With those high temps, I would expect slightly higher than normal output temps at the registers, maybe about 45-55 degrees, max. Maybe you need a re-charge?

 

I've seen 80% referenced in many conversion guidelines. So yeah, following that advice, your system is overfilled. That will certainly decrease performance.

 

You should be able to get a lot cooler than that. I started this thread because I hate seeing R134a conversions get such a bad rap. I'm very happy with mine.

A couple of caveats:

I've got mostly new components in my AC system. (Over the years, I've had to replace every component except the condenser, although the replacements are the same as the original designs.) If running the original compressor, for example, it's at least 30 years old. Even if it was still running on R12, it would have needed to be replaced by now. Same goes for nearly all the components. So I am running the original design, but with new (or nearly so) components. I think a lot of the bad reputation of R134a conversions comes from worn components continuing in service.

I've also added a heater shutoff valve. Details in earlier parts of this thread. It's a very simple mod and really helps keep the outlet temps down. I can't recommend it highly enough.

 

OP judging by your screen name I presume your in Wa. state.

https://seattle.craigslist.org/search/pta?query=r12


I did not read this entire thread, however:

Your AC will work best w/ the refrigerant it was designed for. Find a shop that can charge w/ their or your R12.

My 1986 F250 w/ R12 blows approx. 35* F on a hot day.

 

That is a very expensive way to go, especially since most of these old trucks have small leaks here and there. They can be eventually found, but it's very expensive to keep using r12 till you get them all fixed.

The EPA would rather you get a new truck.

 

35 degrees? That's not A/C, that's a FREEZER!


I'm thinking I'm slightly down on charge, I'll have to check it.

 

I have the factory manual for my 86 ranger. They have A/C performance data in the A/C section, worst case for the system with r12 in it is about 47 degrees temp at the outlets. Clutch cycle times and system pressures vary a lot according to the ambient temps, but the outlet temps hang in there from about 36 to 47 degrees. Of course with the 134a it won't be that cold.

 

Do you think adjusting the pressure cycling switch is recommended and do they need to be adjusted, or are they ok stock as long as they are new and stamped for R-134a?

I plan on adding a heater valve to my '84 and I just found out I have no vacuum at the recirc door servo so that probably has a lot to do with it, but I really don't want to replace the compressor. How can I tell if it's actually bad or worn? It doesn't make any abnormal noise while engaged and even without the re-circ function on, at regular driving speed it is fairly cold.

I've contemplated changing every component next year and switching back to R-12. I have plenty in my stock pile, but if I can get what you're getting with 134a, I'd be happy.

 

If the new switch is stamped R134a, I'd have to assume (danger! danger!) it is preadjusted for R134a pressures. You don't have to change the old one just for that, however, as the switch is adjustable. Between the terminals is a small adjuster screw. CCW 1/8 of a turn lowers the setting 2 degrees. For R134a, 22 psi works well.

Good question. On my truck, it was easy to determine. The clutch was slipping and the shaft seal was leaking. For what it cost for just those parts, it was about the same price for a complete new compressor.

Gauge readings can help decide if a compressor is worn out, but there are so many variables, it makes me reluctant to specify what values you should see. Temperature, RPM, humidity, sun load, condensor airflow, etc., are some of the big variables. An experienced AC guy probably could interpret the gauges without too much trouble, but this is not my strong suit.

For example, low refrigerant can skew the pressure values, but who does a full evac and recharge BEFORE troubleshooting? Without that, you just don't know exactly how much refrigerant you have. Keep in mind the system is typically already operating subpar when we hook up the gauges. It is very common to have low refrigerant, and it would be super easy to incorrectly blame the compressor when the fault was elsewhere.

Sorry I don't have a more specific answer for you. I've done plenty of AC work, but the only time I've had to change a compressor, it was because of the previously mentioned clutch and the shaft seal. I didn't have to evaluate any gauge readings.

 

I lived in southern WA when I created that screen name, but have since moved to The People's Republic of Oregon. To make sure I'd fit in, I built a hologram cloaking device for my F250 so it looks like I'm driving a Hillaru wagon. (That's a Subaru with a dealer-applied Hillary bumper sticker)

As far as locating some R12, that's not an issue. I've got a couple of cases squirreled away, covered in dust.

Agreed, R12 performs better. No argument there.

However, after trying my first R134a conversion just to see what would happen, I was pleasantly surprised. This was during the Dark Ages of AC service, when the general consensus was doom and gloom after R12 availability was severely restricted. Not only would you never enjoy cool air again, R134a would also make your wife run off with another guy, the predictions were that bad.

Is an R134a conversion perfect? No. Is it perfectly adequate? You bet, at least for me, at a fraction of the price. Compared to R12, I think I'm getting great "Cooling per Dollar" value. I'd have to spend a lot more money simply to get those last three degrees of cooling performance. As cheap as I am, I'm very pleased.

Just wondering, does anybody know how much a shop charges these days for a full evac and R12 recharge?