Anyone have experience charging the air in our trucks? I have an '84 r-12 system. I don't know much about fords but I was watching a youtube video and the guy noted that fords are temperamental when charging the system and you should do it by weight not pressure (as opposed to GM's that you can charge by the pressure readings).

I don't really want to retrofit the system to 134a but with the price and availability of r12 I may just do so. Anyone have experience with this? Did it turn out well or what? I used to have a few GM's in the past and I remember the small radial compressors did not like the 134 conversion. They didn't cool well at all at idle. This ford compressor looks like an axial compressor so it might be better. I'm no expert just going off the research i've done in the past. I'm not opposed though to getting a few cans of r12 and just keeping it on the refrigerant it's suppose to be on.

Any input is much appreciated. Hoping to get some cold air this summer in my work rig

Thanks!

 

Yeah the old HR980 compressors, which was a cheap copy of a GM R4, does not like retro all that much. You should have an FS6 on your truck. Retrofitting is easy and if done properly, will leave you very happy and cold.

Required parts:
New accumulator - The old desiccant is not compatible, plus think of it like an oil filter. It's very dirty by now.
New Orifice tube. - If you have the blue tube factory, go to a red, if you have a red tube factory, go to an orange. If you live in a more extreme climate, I would go with Variable Orifice Valve. There are two by temp range
O-ring kit - the old o-rings really need to be replaced, the newer ones are made of a better material.

Recommended parts:
New aftermarket condenser - The new aftermarket units are made to be more compatible with 134. It makes a massive improvement.
New fan clutch. If yours is worn, it will not pull air efficiently. Also make sure that the fins of the radiator are clean and the fan shroud is intact.

You need to flush the remaining parts of the system, or have some one do it for you. I recommend an evaporative style flush, like DuraClean or FJC Extreme Clean.

For a/c oil, it is 8oz of either Ester oil or the newer universal PAG oil, for the entire system, but break it up into at least three places so it is not all in one lump so that it blows seals out, I put ~ 3oz in the compressor, and split the rest between the accumulator and the condenser.

The system must be placed under a vacuum for ~30 minutes to pull moisture out. Then shut the valves and make sure the system does not lose vacuum. I let is sit for @ 10 minutes or 1 beer, depending on the mood.

When charging, you still want to watch pressures as they can tell you if there are other issues in the system, but start out at 80% of factory r12 charge by weight and work your way up till the pressures behave properly. There is really no set pressure, as they are relative to atmospheric conditions, but at idle with the fan on high/recirc, look for around 30-35 on the low and 200-230 on the high. You will also need to adjust the low side cutoff pressure at the switch on the accumulator, I have mine down to about 20-25 It has a pocket screwdriver sized straight slot between the blades. Making a set of jumpers really helps with this step. R134a is less dense than R12 and you have to take this into consideration, so it works at different pressures.

If you look on the guages, there is a temp scale, this is the theoretical temp that you will have at the Evaporator, I try to keep it just north of freezing. My center vent temp in actual usage @ 55 degrees on an 80 degree day.

On the parts sourcing, try to stay away from the big box stores and seek out your local wholesalers and independents. You can be surprised the money you can save on better product, as well as they tend to have the more professional quality supplies. And helping the little guy is always better.

The same process would apply to your GM's as well. The systems are almost identical in function, even the switch is the same.

 

Attention ctubutis!

This information has been covered many times before, but this is excellent information in a very concise form. What do you think about adding this to a sticky in the appropriate location for future reference?

"Rep" to you, Archion!

 

Great write up, Matt. I tried to rep you, but it says I gotta' spread the love.

 

NP Guys, I just try to help where I can. You all actually asked for a write up last year, the round tuits finally came off back order today...

I'll try to remember to edit later with part #'s. I had them in another post at one point.

 

I am not sure I agree exactly. Yes you can replace all those parts, and they will make it cool very well, but all of them are not necessarily needed to change a system out to 134a and have it cool "good enough".

I agree if the system has been open for a extended period of time, or you are installing a new compressor. You can change this out for extra insurance, but if the system has been closed up with the r12 in it, it will work ok with the old accumulator in it.

I have never had to change the orifice tube unless I had a compressor go bad and clog it up. Will it cool better with one of these other orfices, probably, but the 134a has always gave satisfactory performance for me with the original style orifice, especially in the smaller space of a pickup truck cab. If I put the controls on max and the fan on high, and later on I have to turn the fan down to keep from getting too cold, it's cold enough for me

If you think your system has a lot of leaks, and you want to change the o-rings, go ahead. If you do not have any serious leaks, the original o-rings will work.

 

So...not to hijack the thread (OK...), but what's the story here? How much of a difference are we really talking about? I redid my A/C system not too long ago, but it apparently had a leak that the vacuum test didn't reveal, so I'm going to have to go in again. I didn't replace the condenser last time (just the compressor and accumulator), so if there's a real gain to be made I might go ahead and do it.

 

You would be looking at @ 20-25% increase in cooling efficiency if yours is still OEM. But if the system is working fine and you have it charged, don't waste the refrigerant. Just make sure you have good unobstructed airflow. As you have a leak, it could be a good time for you.

 

Dave, we have had this discussion before, yes, you can "make it work good enough" with less steps and parts. Hell I've done it on cars im not keeping. The question was asked on the proper steps, and that is what I gave. Also, my parts vendors will not warranty any parts where the proper documented steps were not followed. They are really starting to crack down on it.

 

Yes, I have bought new or rebuilt compressors and they will not warranty the compressor without changing the accumulator and sometimes the orifice tube.

I just voiced my opinion, there are many different things that come into play, education is one of the main ones. A HVAC guy who is in the business would do things in a different way, vehicles coming back to the shop are not a good way to stay in business. My point is someone messing around at home can do things differently and roll the dice, without losing much except a little time.

 

Huh. That certainly seems worth pursuing, so if I can find a condenser for the dealer air system (NAPA doesn't seem to have one), I might go for it.

Thanks for the info!

 

Id just change the accumulator and put in a adjusting orifice tube $45 quick job.

I have better results with the so called synthetic freon such as "artic freeze" over store brands.

 

OK, done.

Link is to the entire thread since there are some good points brought up throughout.

 

FWIW, I purchased a 1994-96/7 condensor for my truck when I did the EFI conversion. I also used the 96/7 compressor on my truck along with a red orifice tube. I already had a 96 AC box from a wrecked F150. The end result, even down here where the temperature and humidity race to see which one gets higher, you can almost hang meat in the cab. I currently have the carpet out, so it's even more impressive.

Dave, you can cut corners, but given the price of the FS6 compressors, I'm not sure I would want to chance it. Mine now uses an FS10.

 

Your local parts store should be able to inform you about the warranty specifics. Most of them do require the accumulator/dryer and the orifice tube to be changed to comply with the warranty.

The AC flush products are good and not too expensive. Be sure to get plenty of the flush product though. I use rubbing or isopropyl alcohol. If you buy the flush products you can smell the alcohol in them and that is what makes it evaporate.

You wouldnt think it,but,there is a mile of tubing insde the condensor and "A" coil. It will take a little time to flush it all out.The theory behind the flush is to go in the opposite direction of refrigerants path. A back flush if you will. Supposedly if anything is plugged or clogging the lines the back flush will un-wedge it.

One tip for flushing would be to find a bottle that has a cap that will allow you to squirt it in from different angles. A rag on the other end of the tube you are flushing will help keep the old oil and crud from being sprayed all over engine bay. Also it will trap the debris if any coming from out of the system in case you are looking for a culprit.

I would use the orifice tube removal tool if you can. It is easy to make a mess and complicate the removal without one.

Another tip for the DIY AC guy would be there is only one component in an AC system that has moving parts and that would be the compressor. Should you be seeing any trash on the orifice tube or in the system period it just about always has come from the compressor going south. So if there is debris in the system then it is getting to be new compressor time.The accumulator has a a bag of dessicant in it which removes the moisture. It is possible for it to break open and send it through the system. I have personally never seen this happen. My neighbor has been a mechanic for 25 yrs and he has never seen it happen either,but,it is a possibility.