I am getting AC parts to get my F100 system working again.
I have a new condenser, used Sanden compressor (marked 85 F150), going to flush the evap., new dryer & orifice valve (blue I think) and not sure on hoses if new or used or combo of both?

So what oil do I add to the system PAG or Ester?
If PAG what flavor 46, 100 or 150?
How much oil with just a used compressor and the rest either new or flushed out?
When would the oil be added and where? Pull a vacuum and suck it in or pour it in a open hose before a vacuum is pulled?

And maybe the last question how much R134A would it take?
I know it should be weighed but if doing this all at home I would not have access to a scale so wing it with cans and gauges.
Then again I may get everything in place and if I cant get a vacuum pump may farm the charging out so would not really need to know then.

Thanks guys in advance
Dave ----

 

Either will work with R134a.
Ester will work with R12 or R134a.
Mineral oil is original for R12.
If you can borrow, steal or rent a vacuum pump, it is a necessity.
Make sure all connections are tight first then put on the guages.
Blue to the low pressure line ( the biggest size of the two)
Red to the high pressure side ( the smallest size of the two )
Yellow to the vacuum pump.
Open all valves on the guages, then turn on the pump.
let it run for 30 minutes, turn off the red and blue valves on the guages, turn off the pump.
Look at the gauge make sure it reads -30 or close to it. Wait 15 minutes look at the gauge again and make sure it reads the same -30 as 15 minutes earlier.
If the gauge reads the same your good with no leaks. If the gauge reads 0 you have a leak. Go back and check all your connections.
If your good with -30 on the gauge, turn on the vacuum pump and let it run for 1 and a half hours. This will remove all moisture in the system.
When ready to put in the freon turn off all gauges and vacuum pump. Connect can to yellow hose from vacuum pump and open can valve.
Then open the blue gauge valve. Start the truck and turn on ac to maximum with lowest fan blower speed. Stick a thermometer in a ac vent.
If using individual cans of R134a make sure to close the yellow hose on the gauges before replacing the next can. Then open the yellow hose
Again to let freon back into the system. Watch the big line at the evaporator box on the firewall to start sweating. Check the thermometer until it gets to
40 degrees. Keep the truck closed up while it's running look through the glass to see the thermometer and read it.
Your system may use 2 and a half to 3 cans. Cans are 12 oz a pound is 16 oz.
Use the yellow gauge hose to slowly add the freon after the first can and watch the evaporator line for big drops of sweat and once you reach 40 degrees or less
You are good to go.
​​​​​

 

Thanks for the information
I should have said I knew of the vacuum pump and gauge set part.

What I really need to know was the type of oil and if PAG what weight.
Google only comes up with use what ever the compressor manf. says to use?
At 1 point it was use want the car manf. said but because the pump manf. make them for different car manf. it was changed.

So if I use PAG oil what weight, 46 / 100 / 150 and how much? I was told I had to add the oil or they would not warrenty the pump and I know I have to add some with the new condenser and flushing of the evap.

It did help on how much if I charge it myself. I would like to do the full service myself just so I can say I did it but I don't mine shipping it out once I have it all together.
Would be nice to pull the vacuum so I know its tight before sending out but if I go that far might as well charge it right?
Thanks again.
Dave -----

 

FWIW: I read a lot of the contradictory and confusing information about doing a R12 to R134a conversion. It had to be easy because my younger brother was able to accomplish it. He bought a new but more modern compressor as his old one had failed. This was per the parts store guys recommendation.

After reading way too many methods and opinions, I decided I will be sticking with R12 for a while longer. I have an adequate supply stashed.

To your questions on oil, I can only offer my experience as a general guide. I replaced the failed (leaking) compressor on my '97 Riviera four years ago. Remanufactured unit. Instructions called for the type of oil and amount. I had flushed my entire system and replaced the accumulator/dryer. Instructions called for 3oz. of oil. Half poured into the compressor suction, run in by hand and the rest poured into the accumulator. The system is still performing well.

FWIW: My 1986 truck takes 52oz. Of R12. Rule of thumb on conversion is 90% minus 4oz. So, about 43oz. of R134a.

When you're hell bent on doing things right, by the book, it sucks to find so many differing opinions. When I studied on this I determined my 1986 compressor was inadequate. The hoses all need replacing and the condenser wasn't big enough. It needed new pressure switches. The v-belt drive would not have the power to drive the modern, higher pressure compressor. Leaving the evaporator as the only component salvaged from the original system.

Of course, we know we can get by with a lot less.

Best of luck. I'll be monitoring your progress.

 

With the old compressor you are going to have to use Ester oil. Unless you want to take it all apart and get all the old r12 oil out of it.

I am looking at a 1984 factory manual. They say the system requires 10 ounces of oil. A replacement compressor back then came with 10 ounces of oil in it. On a completely new system you leave all 10 ounces in the compressor and install it. If you are putting the new compressor on a system that has been in service, they say to pour out 4 ounces of oil out of the new compressor, and then install it.

If you have a system that has been in service, and are changing just one component, these are the oil values and what you have to manually pour into the component when replacing it.

Evap coil 3 ounces

Condenser 1 ounce

Accumulator-Drain the oil out and measure what you get. Add that to the new accumulator + 1 ounce.

Your system is basically new/flushed clean except the compressor. I would turn the compressor over with a pan underneath it, and slowly rotate it and get all the old r12 oil out of it that you can. I would then see how much ester oil you can get into the compressor, up to 10 ounces. It's not that easy sometimes, you have to turn the compressor as you slowly pour the oil in it, and then sometimes it starts running out. If you can't get the whole 10 ounces in it, I would see how much you did get in it, and then pour the rest in the evap coil and the condensor. When it's in the evap coil, the compressor will suck it right in. The oil is for the compressor, nothing else, So you have to make sure it has oil in it if it's turning.

 

Use CoolPro PAG 46.
You only need 6 oz.
Some say put 2 oz. In compressor, 2oz in dryer and 2 oz in condenser.
Others say put it all in the compressor.
the manufacturer puts it all in the compressor and your good to go to hook it up.
I like to drain the compressor into a measuring cup of it came with oil and make sure what is in there.
I add the oil to the compressor. The receiver dryer will go bad if you leave it open to the atmosphere for more than 30 seconds.
when you put a vacuum on the system the refrigerant will suck into the system ( at least the first pound or can ) by itself.
The compressor will pump the oil throughout the entire system.
Putting oil in separate components will make a mess as it leaks out during installation. Not to mention trying to pour oil in a receiver dryer
Within 30 seconds

 

After reading these responses and other inquiries on the subject I must’ve been lucky. When I bought my truck 20+ years ago the ac system worked but wouldn’t cool. Not having any spare cash then I just worried about keeping it running. About 15 years ago I bought a 134a conversion kit that came with high/low fittings and a fill hose. I put a can of Freon in then a small can of ester oil then almost 2 more cans of Freon and it blew very cold air. I’ve added a can of Freon and/or oil ever so often but it’s still working as of now. I cruised around in it yesterday and it’s 90+ temps here and the air was blowing a cold 47 degrees.

 

Hiya Dave,

Ready to get totally confused? Years ago, I ran into the same wide range of opinions on converting to R134a. Here's what I did on my '84, with the same Sanden compressor. I did the initial conversion around 1997 or so. No flushing, no new oil, just a new receiver/dryer, followed by a full evac and refill with R134a. Worked great for about 15 years, no complaints there.

Eventually, the original compressor succumbed to old age. Was this due to the conversion? I don't really think so, as it went 15 years like that. I think it was around 2012 that I replaced it with new. At the time, I flushed the rest of the system with an aerosol cleaner. I broke open all connections and blew out each component in reverse. I replaced the R/D again, and went with a new orange orifice tube. I filled the system with R134a to 80% of the R12 capacity, a standard value for a conversion. Once again, the system worked great.

For oil, I used PAG 150. I do not remember how I decided on that at the time. All I know is that's what I decided then, and it has worked for me. I poured a little into the compressor inlet and turned the pulley face to distribute the oil. I poured the rest into the R/D, as that is where most ends up anyway. I forget how much total I used, whatever the factory manual said.

I wouldn't worry too much about how much oil to use and where to add it. The service manual says to add X amount if replacing a certain component. That's just a general guideline based on how much oil typically collects there in service. I prelubed the compressor to make sure it didn't start up dry. The rest will distribute itself.

Add the oil before the vacuum evacuation. Oil doesn't boil off and turn to vapor like water does during the evac.

For adding refrigerant, I've never bothered with a scale. For each 12 ounce can, I've guessed maybe an ounce gets left behind. I figure about 11 ounces per can is a good estimate.

When attaching a new can, expect some ambient air to get into the fill line to the manifold. You should have a little purge valve where the center (fill) line attaches to the manifold. To purge this ambient air, close both manifold valves and open the valve at the can. Momentarily press the purge valve and the pressurized refrigerant from the can will expel any ambient air. Two seconds or so is plenty. This purge action is part of why I only figure about 11 ounces from each can.

 

Not lucky. Many people do that with success. I don't know what it is about certain trades, but the HVAC trade is bad about making things too complicated and hinting that they are the only ones that can work on HVAC equipment. They had it all tied up in the early years with the special expensive equipment you needed. And in the housing side of it, they had it all tied up with being able to buy a furnace or a A/C unit at all without a license.

Now those barriers are gone. You can go right down to Harbor Freight and get a set of gauges and a decent vacuum pump at a reasonable price. And on the house side, you can go right down to Home Depot and buy your own furnace or A/C unit, conventional or split type. The job I am working at now required me to work on this stuff, I have had some classes and got my gas license, but like everything else, they do teach you anything about real world repair and installation.

But a regular person that has the ability to study and learn and can read books and find out how to do things, can work on HVAC stuff. It's not ideal, I think learning on the job from a experienced person would be best, but it can be done.

But back to your comment, I have found out a lot of this stuff is not that critical. The amount of freon in the system is not that critical. So long as it cools good enough for your purposes, and you don't overfill it too much, it's going to work. Like anything else, if you do mess up it's not necessarily the end of the world. We all make mistakes. I overfilled my wife's car once, she was in town and the belt started squealing. She knew I had been working on the A/C and quickly turned the A/C off and the squealing stopped. When I came home I let the excess charge out and it has been working ever since, that was over 10 years ago.

On the 30 second opening on the dryer. I don't know where that came from. Yes, it's best to not have it open more than you need to. But you certainly can have it open long enough to pour oil in it, and install it. I have actually put my shop compressed air into a system and soaped the fittings up to find a leak. I have done this several times. Is it good practice? No. But I don't have a nitrogen setup here at home. Did it ruin the system? No. I put the vacuum pump on it for the whole day after I had found the leak, charge it with freon, and the system works fine.

How do a charge my wife's Honda accord? It has a very small leak, every couple of years it needs a charge. I just hook the can to the charge hose on the low side, no gauges or anything. She is sitting the car with the A/C on high max, while I am letting the 134a go into the system. She is holding her hand in front of the vent. When she says it's cold enough, I stop filling and close the system back up. Been doing it this way for years. The one time I did overfill it, I was using a single gauge on the low side, with all the windows up and the button on max A/C. The windows rolled up was my mistake on that one.

 

I've done the same with compressed air, and all was groovy. Like you, I pulled a vacuum for a long time to make sure all moisture was drawn out.

Do you have a MIG welder? I added a tee fitting so I can use the gas bottle and regulator to pressurize the AC system for a leak check. My thoughts are the bottle contents are drier than compressed ambient air. Less moisture in means less to draw back out.

 

Thanks guys that is a lot of information to take in.
I have to take down notes to keep track what and how much of what ever it is so come time I don't need to read thru all this again.
Dave ----

 

I just did that on my 84 F150. PAG 46 definitely

 

PAG 46 is a synthetic oil for R134a refrigerant.
I've decided to restore my dealer installed air conditioning on my 86 f150. It uses a Ford HR980 compressor. Just got lucky on fleabay and bought a NOS one in the box.
I've read that it is wise to go with a larger condenser if you are converting a R12 system to a R134a refrigerant.
You might want to consider using a later model condenser that was designed for R134a to give you a more compliant system. The later model trucks use them and should bolt in place.
Really no difference in a compressor or dryer. They do what they were designed to do. The condenser being larger makes the system much more efficient.

 

PAGE 46 is fine with 134a but what if you still have a little R12 oil left in the system? That is the real question because I don't know what my used compressor came from?

As for the condenser you can only get 1 that fits the later trucks, don't know the system it is used on, but it is not a bolt in to our trucks. It is already installed because I did not want to R&R the radiator just to install it.
What you do have to make sure of is the opening in the radiator support is for AC as it is a larger opening.
Dave ----

 

Best oil to use if you have a R12 system your converting to R134a would be ester oil. It can be used with either refrigerant.
Just flush out your condenser with solvent and install a new receiver dryer.
I would flush out all the hard lines with solvent since your going to install new o-rings too.
The cleaner the system the better.