A/C 1985 retro fit

I need some interjection of advice. Here is a topic we can get our teeth into and here is what has transpired. 

1. Bought a 1985 Bronco project truck. It was, at one time, a Eddie Bauer XLT but you would not know that now. It is FUGLY
2. The Compressor does not cycle.
3. No cold air
4. I pushed on the R12 low pressure valve and nothing came out. The system appears dry.  
5. Placed the new 134 valve and charged the unit 
6. The compressor started cycling every five seconds. This tells me that it recognized it had 134
7. Air seems not to be cold or even less than warm
8. Took it for a test drive and it is still cycelnig but air is still warm

Tomorrow I am going to add more 134. I used 1/2 bottle, maybe 16 oz. today. What do you think? $-)  

not enough. probly will take 1-2 more cans

yo J,

All I can offer now is this;

Conversion in an 89; "...I have converted mine from R12 to R134A, and it cools the truck much faster. The first thing you need to do is replace ALL of your "O" rings. **** them with a small amount of Vasoline, USE NOTHING ELSE. Since it hasn't been used in a while, go ahead and replace the Expansion Valve, and the Reciever/Drier. You can pick all of these up at your local Autozone(the O rings come in an assortment pack, so get 3 packs to make sure you have what you need). Replace them now, it WILL save you money in the end. Then, you will need to go to an A/C service center to have your system Vaccumed out to a negative 3 lb's. This will clean out any R12 left in the system, and allow you to get enough R134A in there to cool properly. Most of the problems you hear about R134A, is because they didn't draw the system down to negative pressure. You will need to disconnect the harness that connects to your Reciever/Drier, and make a female to male spade jumper, to bypass the Low Refrigerant switch(you'll see what to do when you pull it), to get the compressor to come on. Install the adapters, and charge it up following the instructions. Don't forget to reconnect your Low Refrigerant switch when finished. Depending on your system type, you may need more refrigerant than the kit supplies. I had to add about a half extra can to get up to the proper pressure. You can get this kit at Walmart, and Autozone too. Why wait on shipping to save 50 cent ?..."

Source: by sweepersrgr8 at Ford Bronco Zone Forums

Conversion in an 85

Source: by David L (Converted) at http://www.supermotors.net/clubs/superford/vehicles/registry/1004/7522

◦Charge with 134a between 70-80% of the original "R12" charge amount

http://www.classicautoair.com/FORD_OEM_Parts_134A_Conversion.html?

Refrigerant Capacity, Ford

1984-90

Bronco, F-Series Pickup 52oz of "R12"

Source: by http://web.archive.org/web/20100309034811/http://www.aircondition.com/dsmobileac/ford_truck.html

RETROFITTING TO R134a

A retrofit from R12 to R134a requires less gas. LOOK UP THE PROPER R12 CHARGE! DO NOT GUESS! Calculate 70% of the correct R12 charge and start by putting in that amount. Give the system some time to stabilize and if you have cold air stop. If not keep adding in small increments until the air gets cold. Monitor pressures with your gauges keeping in mind the normal readings for your system which you also LOOKED UP. How cold an AC system gets is determined by the low side pressure. The lower the low side pressure, the colder the system. Adding gas beyond optimal pressure will decrease the systems efficiency and eventually raise the low side pressure. Lowering it too much (beyond the manufacturers specifications) will cause freeze ups and the activation of system electrical switches designed to shut the system before freeze up occurs. That is why you do not want to significantly deviate from the manufacturers suggested charging parameters. When you are done affix a label to the evaporator case or somewhere under the hood indicating the amount and type of gas used for the charge, the amount and type of oil, the date, the pressures read on the gauges and the ambient (outside) temperature. All of this information will be useful in the event you have to service the system at some time in the future.

http://www.polarbearinc.com/Trouble10_retrofit.htm

Doesn't blow cold.

1. Is the compressor clutch engaged? You can tell this by seeing if the front "hub" or drive plate is drawn in when the system is turned on. You will usually hear a "clicking" noise when this happens. If it is engaged, you need to shut it off and put a set of gauges on the system. If you have only a low side gauge that comes with the DIY charge kits, use that. It is better than nothing. Normal readings should be in the 30 psig on the low side and 180 psig on the high side range. These are approximations as each system is different so you will have to look up the pressures for your particular vehicle. What matters is that the low side is close to 30 psig and that the high side is not outrageously high or low. The low side dictates the degree of cold. The lower the low side reading, the colder your system will be. Too low, and your evaporator will freeze and stop blowing cold after a while. Optimally, you want a low side in the high 20s to low 30s.

If you do not have gauges, feel the evaporator suction pipe. It is connected to the largest hose in the system, which runs from the suction side of the compressor to the evaporator. If it is cold, that means your evaporator is cold. If you have warm air coming out your vents and a cold evaporator, the problem is most probably in your vent system in your dashboard. Check all your vacuum lines (many of the switches are controlled by vacuum), and look for stuck damper doors that control the flow of hot and cold air and the degree to which it is mixed. A door stuck in the wrong position will prevent the cold air from reaching the vents.

http://www.polarbearinc.com/Trouble7_diagnosis.htm#Doesnt

more info @ http://www.polarbearinc.com/Trouble1.htm

AHA !!!!!     I took your advice and added most of another can. The compressor stayed engaged and the air blows cold. The gauge does not read but about 1/3 into the green area and at the low end of the "V" temperature spectrum. I think letting it "stabilize" as, you mentioned is the best thing to do. This cost me $52.97. A far cry from the $520.00 quoted by a well known auto repair shop. Thank you friends, for your help. Now I just need to keep my fingers crossed that the system does not leak it back out. The first can was A/C Pro with leak stop in it. So far things look good.  >-

Hey J,

Congrats on your cold air. While I don't have the intentions of raining on your parade, you may have created a future disaster.

Converting to a 134 system is more than just changing port fittings.  The system has to be flushed and evacuated. R-12 and R134 don't play well together. The oil has to be flushed and replaced with ester oil that is compatible with the 134 and any trace of old refrigerant oil. Vacuuming to min 28in/m as M5 said is necessary to remove any air and moisture.  Failure to do so will result in acid being created, the oil becoming a sludge and eventual failure of the entire system requiring replacement of every component.  The proper procedure would have each line and component opened and flushed,  the O rings replaced and proper oil replacement.  This will ensure a system that will provide cold air for a long time.  (I have an 85 S-10 with such a conversion done 12 years ago...still working well.)

It sounds like you did a charge with a "trigger" bottle that just has low side general pressure readings.  This could be dangerous if you don't know the high side readings.

If you haven't done a complete conversion you will have cold air....but it will not be sustained and the damage resulting could be catastrophic.

Again...my intentions are not to discount your success but to inform you of potentials.

Good Luck

Hmmmmmmmmmm/ This could be serious. I called several shops to see if some one would evacuate the system but no one had the equipment. I guess the next best thing to do is to find a shop that will do the complete job for the best  price.  I may need to travel to Houston. That is the last thing I want to do. It looks as though the critical issue is the oil. There was no pressure in the low pressure line when I pushed on the valve. 

Thank you for your information. I am now disappointed, grateful and informed. :glare:

Hey J,

Sorry it has turned to such a hassle getting an evac and recharge....here in Fla. there are AC shops on every corner.

Good Luck  

You can get an idea whether there is oil in your system by using something like the head of a finish nail to press the stem of the low pressure port for a fraction of a second while the A/C is running, so the 134a and any oil that is circulating squirts out on your fingers.   When the 134a evaporates the oil is left on your fingers.   If you have a lot of oil, it will likely be the wrong oil and should be removed, however, I would guess there is little oil in such an old system.   You can buy small oil charge cans that have a few oz of the correct oil in a bit of 134a.   The can is held upside down so the oil is forced into your system.   A couple of cans of oil charge should provide the lubrication your system needs.   There is some compatability of the new oil with the old oil.

There are a number of "shortcuts" that can be done to get you cold air....for awhile.  Adding oil will still not evacuate the moisture and prevent the acid from forming. There is a definite procedure for assuring a clean, safe, properly charged system.

I would never recommend opening a port while the system is running even for a second. It is dangerous. It has always been the mantra on this forum to promote safe work on any vehicle.

In the end it is you that has free will to decide what you wish to do.

​Hmmm,. the oil., I mean plot thickens. My theory when deciding to put the 134 into the old system was that if it failed I was faced with a major five hundred dollar expense to evacuate, change "O" rings and recharge the system in any case. So if the new 134 caused the compressor to fail, I still would be faced with a major five hundred dollar expense. Now that I have gone this far (I am afraid to run the A/C at this point) it seems reasonable to find this oil and add it to the system. 

Rons beast said:

There are a number of "shortcuts" that can be done to get you cold air....for awhile.  Adding oil will still not evacuate the moisture and prevent the acid from forming. There is a definite procedure for assuring a clean, safe, properly charged system.

I would never recommend opening a port while the system is running even for a second. It is dangerous. It has always been the mantra on this forum to promote safe work on any vehicle.

In the end it is you that has free will to decide what you wish to do.

Click to expand...

I think you may be overstating the danger of pressing on the core of a schrader valve briefly.   Yes, stuff will shoot out until you stop pressing on the core.  

Since he had no pressure in his system, he has a leak somewhere.   Once he finds what is leaking he will have to fix the leak and should at that time replace the dryer, which will remove any water that might have entered the system. 

Ok in the interest of safety and proper information, everyone should READ all information posted here.

Just adding the proper oil will not ensure a trouble free AC system converted from R-12 to R134. There is a procedure. There are necessary changes, there are proper tools, and there are reasons for them. 

I will not be pulled into a debate over weather something is safe or not or OK or not.

The information is here and available. All that read have free will to do as they wish, but I will not condone or support using a fastening device to open an AC port under pressure or otherwise...even for a moment.

Additionally in the case of Jgrden, 134 was added without the benefit of pre evacuation and vacuuming so any moisture has now already been mixed with the Freon and is forming acid.

A professional AC center would use the tools and the procedures that would indicate if there were a leak that would not allow the containment of the new Freon for a reasonable time.  (The evacuation process and vacuum hold test.)

My point was to inform all that take the time to read the entire post that the decision to take "shortcuts" could be creating a situation less than favorable, and far more expensive to recover from.

Make your own decisions...but all have the information before them.. 

Good information. Here is what I am proposing.  Since the system is functioning I think saving it is a good idea. My neighbor has the gauges needed to monitor the pressure in both valves. My confusion is the compressor. I have been told that it is  necessary to remove the compressor in order to drain the old oil. Is this true? Secondly, I can buy a vacuum  machine at Harbor Freight for $20.00.. There are "O": rings - where are they? They need to be replaced. So here is my thought:

1. Hook up gauges to vacuum and **** the old 134a out and leaving the lines with no pressure
2. Remove this lines to the compressor and remove the compressor (if necessary {couldn't there be a drain plug?})
3. Drain the old oil
4. Flush the lines with the stuff sold to O'Reilly's or Auto Zone Can this be done without the compressor hooked up and the engine off?
5. Reconect the compressor with new Ester Oil
6. Hook up the vacuum and **** the heck out of the system to capture any residue including moisture.
7. Leave in a Macumba state foe thirty minutes, at what level vacuum (cannot call it pressure when it is a vacuum).
8. shut the valves leaving the vacuum intact
9. Hookl up the new 134a and fill it. 

:-B What do you think?  Your comments seem to be correct and by the book. 

Please and thank you for your help. Don't get discouraged. Keep up the good work. I guess the missing link is that there is suppose to be a leak. Do I want to go through the labor and expense of putting dye in the system? Probably !  So how ?

Thank you for your patience. I bought this truck because I have always wanted one. I want to do the work myself for two reasons, self satisfaction and expense. Your advice has helped me and perhaps saved a system that is in good shape.

You may think you are saving money but I would pay attention to what Ron told you.  There is a reason for having experienced people do your A/C.  You need to have the proper tools and have the experience of how to use them properly.  As old as your system is, more than likely some components will need to be replaced and requires experience to accomplish properly.  Yhere are a million ways to do the job wrong and only one way to do it right.  That is why A/C shops exist.

In most other areas I would suggest you take a wack at it, that is how you learn but not in this case.  In other cases, have a back up plan in case you find out you can't properly and safely complete the task.

>-

OK Jgrden,

I think as Seabronc said you may want to leave this to the pros...however I applaud your willingness to try this on your own. 

First off use the proper safety equipment. Safety glasses are essential. I would be without one eye if I hadn't had a pair on when working on one old vehicle.

Gloves are needed too. Your gauges (or the neighbors) should be in good shape with no cracked hoses or broken parts.

The vacuum pump you purchase MUST be able to vacuum an AC system to a minimum 28 in/ hg.

Connect the gauge set with the center ( yellow) hose in a metal can or plastic bottle.

Engine off of course, Open the low side valve slowly and allow the Freon to escape at a slow pace. Be patient. When the hissing is appeared to be stopped, open the high side valve and allow any residual freon to escape.

You may now proceed to remove the compressor. ( sorry there isn't any drain.) turn it with the port side down in a pan to collect the oil.

Important! save the oil and measure what came out. Compare this with what is the normal capacity of your type of compressor. ( sorry I don't have that info, I'm sure someone on here does.)

Now you have to examine all the lines and disconnect them where there is any connections. ( This may require  special tools to unlock the fittings.)

Remove the expansion valve and leave it out to help allow flushing the evaporator. (replace it with a new one.)

After all the lines are disconnected you can use the flushing fluid ( probably will need 2 bottles) to clean out each line and component. Put a rag at the outlet point of each component you flush to catch oil, and debris.

 Do NOT flush the compressor.

 Do not flush the receiver drier ( accumulator) get a new one.

Allow the cleaning fluid a little time to dry.

Replace the oil in each component with new ester oil. 2oz in the evaporator, accumulator and condenser and about 1oz in each line. 

Be sure to have enough oil to fill the compressor to the proper capacity.

**** all the new O-rings with ester oil and install each component and connect all the lines. Remember to install a new expansion valve.

Install the compressor with the correct oil. ( It can be a bear to get it in place without loosing oil. A little loss is ok..alot and you need to re-measure and start over.

Once the system is all back together, allow some time for the oil to run into the reservoir at the bottom of the compressor. 10 min should be good.

Hook the gauges back up and connect to the vac pump. Vacuum for a min 20 min. I prefer 30 here in Fla. where it's humid. be sure you have both low and high side ports open. ( some vapor from the vac is normal for the first few min.)

The vacuum should reach at least 28 in/hg and stay there.

After the vacuum time, close both valves while the pump is on and effectively seal in a vacuum.

Look at the gauges.....wait for 10-20 min. (yeah 30 is even better.) to see if the vacuum held.  If so your good!  If not, you have a leak, ( .  Got to trace that down. Better going to the pros that have the proper leak detection equipment. 

If your vacuum holds, you can tap a can of R134, purge the line to the gauge  manifold and add Freon to the low side only. Most of the first can will be sucked in by the vacuum.

Start the engine. Set idle around 1800 rpm. turn the air on max, the fan on high speed.

Follow this procedure to add additional Freon to the spec for your truck. (As Al said above about 70% of R-12 capacity.)

As you add Freon the compressor should recycle less frequently.  ( you should not have to jump the LPS, but may have to initially)

Watch your gauges.   Low side should be between 15 and 40 and high no higher than 300.

This should get you good cold air, and a reliable system. 

Now remember, you need to buy the Freon, the flushing fluid, an accumulator, expansion valve, ester oil, and O-rings...and do all this work...and you are your own warranty.   

Good Luck

Absolutely perfect!!!!! I am moving ahead. Thank you !!!

I hav e the vacuum pump and the gauges. My next step ts to vacuum the system. there still is doubt as to flushing the system is necessary. After the system is vacated the compressor comes off and the oil drained. I am wondering how we know the old oil and  any residue is finally gone and it does not interfere with the new Ester oil. Any ideas? How do I know the old residue will not interere with the new oil? What the heck I guess we have been doing this for years and I just need to have some faith. 

The flushing of the system with approved flushing solvent is for the purpose of cleaning out the majority of any remaining oil and /or other contaminates.

Ester oil is compatible with small amounts of refrigerant oil as well as PAG oil. However R134 doesn't mix well with older refrigerant oil.

This is why the compressor is drained and refilled with the ester oil.

To do the job correctly the system must be flushed. 

For clarity, let me add this;  Vacuuming the system removes moisture by making it boil, (water boils at room temp. when in a vacuum.) The resultant gas (steam) is then pulled out. 

"Vacuuming" the system  is not like vacuuming your carpet. It does not remove the oil or contaminants that are not attached to any steam. 

Hope this helps.